UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(X)		Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of ~~1934~~1934for ~~for~~ the fiscal year ended December 31, ~~2011~~2012.
		OR
( )		Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for the transition period from to .

Commission File Number	Exact name of registrant as specified in its charter; State of Incorporation; Address and Telephone Number	IRS Employer Identification No.
CommissionFile Number	Exact name of registrant as specified in its charter;State of Incorporation;Address and Telephone Number		IRS EmployerIdentification No.
1-14756	Ameren Corporation	~~43-1723446~~	43-1723446
	(Missouri Corporation)
	1901 Chouteau Avenue
	St. Louis, Missouri 63103
	(314) 621-3222
1-2967	Union Electric Company	~~43-0559760~~	43-0559760
	(Missouri Corporation)
	1901 Chouteau Avenue
	St. Louis, Missouri 63103
	(314) 621-3222
1-3672	Ameren Illinois Company	~~37-0211380~~	37-0211380
	(Illinois Corporation)
	300 Liberty Street
	6 Executive Drive
	Peoria, Illinois 61602
	Collinsville, Illinois 62234
	(309) 677-5271
	(618) 343-8039
333-56594	Ameren Energy Generating Company	37-1395586
	(Illinois Corporation)
	1500 Eastport Plaza Drive
	Collinsville, Illinois 62234
	(618) 343-7700

Securities Registered Pursuant to Section 12(b) of the Act:

The following security is registered pursuant to Section 12(b) of the Securities Exchange Act of 1934 and is listed on the New York Stock Exchange:

Registrant		Title of each class
Ameren Corporation		Common Stock, $0.01 par value per share

Securities Registered Pursuant to Section 12(g) of the Act:

Registrant		Title of each class
Union Electric Company		Preferred Stock, cumulative, no par value, stated value $100 per share
Ameren Illinois Company		Preferred Stock, cumulative, $100 par value per share Depository Shares, each representing one-fourth of a share of 6.625% Preferred Stock, cumulative, $100 par value per share

~~Table~~Indicate by checkmark if each registrant is a well-known seasoned issuer, as defined in Rule 405 of ~~Contents~~the Securities Act.

Ameren ~~Energy~~Corporation ~~Generating~~Yes ~~Company~~(X) ~~does~~No ~~not~~( ~~have~~) ~~securities~~Union ~~registered~~Electric ~~under~~Company ~~either~~Yes ~~Section 12~~(b ) or 12No (gX) ofAmeren ~~the~~Illinois ~~Securities~~Company ~~Exchange~~Yes ~~Act~~( of) ~~1934.~~No (X)

Indicate by checkmark if each registrant is anot ~~well-known~~required ~~seasoned~~to ~~issuer,~~file asreports ~~defined~~pursuant ~~in Rule~~to ~~405~~Section 13 or Section 15(d) of the ~~Securities~~ Act.

Ameren Corporation Yes (X ) No ( X) Union Electric Company Yes ( ) No (X ) Ameren Illinois Company Yes ( ) No (X ) ~~Ameren Energy Generating Company Yes ( ) No (X )~~

Indicate by checkmark ifwhether ~~each~~the ~~registrant~~registrants: is(1) have ~~not~~filed all reports required to ~~file~~be ~~reports~~filed ~~pursuant~~by to Section 13 or ~~Section~~ 15(d) of the Securities Exchange Act. of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) have been subject to such filing requirements for the past 90 days.

Ameren Corporation Yes ( X) No (X ) Union Electric Company Yes ( X) No (X ) Ameren Illinois Company Yes ( ~~) No (~~X ) ~~Ameren Energy Generating Company Yes (X )~~ No ( )

Indicate by checkmark whether ~~the~~each ~~registrants:~~registrant ~~(1) have~~has ~~filed~~submitted ~~all~~electronically ~~reports~~and posted on its corporate website, if any, every Interactive Data File required to be ~~filed~~submitted ~~by Section 13~~and orposted ~~15(d)~~pursuant to Rule 405 of ~~the~~Regulation ~~Securities~~S-T ~~Exchange~~(§ ~~Act~~232.405 of ~~1934~~this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to ~~file~~submit ~~such reports),~~ and ~~(2) have~~post ~~been subject to~~ such ~~filing requirements for the past 90 days~~files).

Ameren Corporation

Yes

)

(

)

Union Electric Company

Yes

)

(

)

Ameren Illinois Company

Yes

)

(

)

Ameren Energy Generating Company (1)

Yes

(

)



Ameren Corporation	Yes	(X)	No	( )
Union Electric Company	Yes	(X)	No	( )
Ameren Illinois Company	Yes	(X)	No	( )

~~(1)~~Indicate Asby ~~indicated~~checkmark ~~above,~~if ~~Ameren~~disclosure ~~Energy~~of ~~Generating~~delinquent ~~Company~~filers pursuant to Item 405 of Regulation S-K (§ 229.405 of this chapter) is not ~~required~~contained toherein, ~~file~~and ~~reports~~will ~~under~~not ~~the~~be ~~Securities~~contained, ~~Exchange~~to ~~Act~~the best of ~~1934.~~each ~~However~~registrant’s knowledge, ~~Ameren~~in ~~Energy~~definitive ~~Generating~~proxy ~~Company~~or ~~has~~information ~~filed~~statements ~~all~~incorporated ~~Exchange~~by ~~Act~~reference ~~reports~~in ~~for~~Part ~~the~~III ~~preceding~~of 12this ~~months~~Form 10-K or any amendment to this Form 10-K.

~~Indicate~~Ameren byCorporation checkmark whether each registrant has submitted electronically and posted on its corporate website, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (~~§ 232.405 of this chapter~~X) ~~during~~Union ~~the~~Electric ~~preceding~~Company ~~12 months~~ (orX) ~~for~~Ameren ~~such~~Illinois ~~shorter period~~Company ~~that the registrant was required to submit and post such files~~(X).

~~Ameren~~Indicate ~~Corporation~~by ~~Yes~~checkmark (Xwhether )each Noregistrant (is )a ~~Union~~large ~~Electric~~accelerated ~~Company~~filer, ~~Yes~~an (Xaccelerated )filer, Noa (non-accelerated )filer ~~Ameren~~or ~~Illinois~~a ~~Company~~smaller ~~Yes~~reporting (Xcompany. )See Nodefinitions (of )“large ~~Ameren~~accelerated ~~Energy~~filer,” ~~Generating~~“accelerated ~~Company~~filer,” ~~Yes~~and (X“smaller )reporting Nocompany” (in )Rule 12b-2 of the Exchange Act.

~~Indicate~~LargeAcceleratedFiler byAcceleratedFiler ~~checkmark~~Non-acceleratedFiler ifSmallerReportingCompany ~~disclosure~~Ameren ofCorporation ~~delinquent~~(X) ~~filers~~( ~~pursuant~~) to( ~~Item 405~~) ~~of Regulation S-K~~ (§ ~~229.405 of this chapter~~) isUnion ~~not~~Electric ~~contained~~Company ~~herein,~~( ~~and~~) ~~will~~( ~~not~~) be(X) ~~contained,~~( to) ~~the~~Ameren ~~best~~Illinois ofCompany ~~each~~( ~~registrant’s~~) ~~knowledge,~~( in) ~~definitive~~(X) ~~proxy~~( ~~or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.~~ )

~~Ameren~~Indicate ~~Corporation~~by ~~(X)~~checkmark ~~Union~~whether ~~Electric~~each ~~Company~~registrant (is )a ~~Ameren~~shell ~~Illinois~~company ~~Company~~ (X)as ~~Ameren~~defined ~~Energy~~in ~~Generating~~Rule ~~Company~~12b-2 (Xof the Act).

~~Indicate~~Ameren byCorporation ~~checkmark~~Yes ~~whether~~( ~~each~~) ~~registrant~~No is(X) aUnion ~~large~~Electric ~~accelerated~~Company ~~filer,~~Yes an( ~~accelerated~~) ~~filer,~~No a(X) ~~non-accelerated filer~~Ameren orIllinois aCompany ~~smaller~~Yes ~~reporting~~( ~~company.~~) ~~See~~No ~~definitions of “large accelerated filer,” “accelerated filer,” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.~~ (X)

~~LargeAcceleratedFiler~~As ~~Accelerated~~of ~~Filer~~June 29, ~~Non-acceleratedFiler~~2012, ~~SmallerReporting Company~~ Ameren Corporation ~~(X)~~had (242,634,671 )shares (of )its ($0.01 )par ~~Union~~value ~~Electric~~common ~~Company~~stock (outstanding. )The (aggregate )market ~~(X)~~value (of )these ~~Ameren~~shares ~~Illinois~~of ~~Company~~common stock (based )upon (the )closing ~~(X)~~price (of )the ~~Ameren~~common ~~Energy~~stock ~~Generating~~on ~~Company~~the (New )York (Stock )Exchange ~~(X)~~on (June 29, 2012) held by nonaffiliates was $8,137,966,865. The shares of common stock of the other registrants were held by Ameren Corporation as of June 29, 2012.

~~Indicate~~The bynumber ~~checkmark~~of ~~whether~~shares outstanding of each registrant’s isclasses aof ~~shell~~common ~~company~~stock (as ~~defined~~of inJanuary 31, ~~Rule~~2013, ~~12b-2~~was ofas ~~the Act).~~ follows:

Ameren Corporation Yes ( ) No (X ) Union Electric Company Yes ( ) No (X ) Ameren Illinois Company Yes ( ) No (X ) Ameren Energy Generating Company Yes ( ) No (X )



Ameren Corporation	Common stock, $0.01 par value per share: 242,634,671

Union Electric Company	Common stock, $5 par value per share, held by Ameren Corporation (parent company of the registrant): 102,123,834

Ameren Illinois Company	Common stock, no par value, held by Ameren Corporation (parent company of the registrant): 25,452,373

~~Table~~DOCUMENTS ofINCORPORATED ~~Contents~~BY REFERENCE

AsPortions of ~~June 30,~~the ~~2011,~~definitive ~~Ameren~~proxy ~~Corporation~~statement ~~had 241,586,534 shares~~ of ~~its~~Ameren ~~$0.01~~Corporation ~~par~~and ~~value~~portions ~~common stock~~of ~~outstanding.~~the ~~The~~definitive ~~aggregate~~information ~~market~~statements ~~value~~ of ~~these~~Union ~~shares~~Electric ofCompany ~~common~~and ~~stock~~Ameren ~~(based~~Illinois ~~upon~~Company ~~the~~for ~~closing price of~~ the ~~common~~2013 ~~stock~~annual onmeetings ~~the~~of ~~New~~shareholders ~~York~~are ~~Stock~~incorporated ~~Exchange on that date) held~~ by ~~nonaffiliates~~reference ~~was~~into ~~$6,967,355,641.~~Part ~~The~~III ~~shares~~ of ~~common~~this ~~stock~~Form ~~of the other registrants were held by affiliates as of June 30, 2011~~10-K.

~~The~~This ~~number~~combined ofForm ~~shares~~10-K ~~outstanding~~is ofseparately ~~each~~filed by Ameren Corporation, Union Electric Company, and Ameren Illinois Company. Each registrant’s ~~classes of~~hereto ~~common~~is ~~stock~~filing ason its own behalf all of ~~January 31,~~the ~~2012~~information contained in this annual report that relates to such registrant. Each registrant hereto is not filing any information that does not relate to such registrant, ~~was~~and therefore makes no representation as ~~follows:~~to any such information.

Ameren Corporation		Common stock, $0.01 par value per share: 242,634,742
Union Electric Company		Common stock, $5 par value per share, held by Ameren Corporation (parent company of the registrant): 102,123,834
Ameren Illinois Company		Common stock, no par value, held by Ameren Corporation (parent company of the registrant): 25,452,373
Ameren Energy Generating Company		Common stock, no par value, held by Ameren Energy Resources Company, LLC (parent company of the registrant and subsidiary of Ameren Corporation): 2,000

Table of Contents

~~DOCUMENTS~~TABLE ~~INCORPORATED~~OF ~~BY REFERENCE~~ CONTENTS

Portions of the definitive proxy statement of Ameren Corporation and portions of the definitive information statements of Union Electric Company and Ameren Illinois Company for the 2012 annual meetings of shareholders are incorporated by reference into Part III of this Form 10-K.



		Page
GLOSSARY OF TERMS AND ABBREVIATIONS		1
Forward-looking Statements		3
PART I
Item 1.	Business	5
	General	5
	Business Segments	5
	Rates and Regulation	5
	Transmission and Supply of Electric Power	10
	Power Generation	11
	Natural Gas Supply for Distribution	14
	Industry Issues	14
	Operating Statistics	16
	Available Information	18
Item 1A.	Risk Factors	18
Item 1B.	Unresolved Staff Comments	26
Item 2.	Properties	27
Item 3.	Legal Proceedings	28
Item 4.	Mine Safety Disclosures	29
Executive Officers of the Registrants (Item 401(b) of Regulation S-K)		29

PART II
Item 5.	Market for Registrants’ Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities	31
Item 6.	Selected Financial Data	33
Item 7.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	34
	Overview	34
	Results of Operations	35
	Liquidity and Capital Resources	54
	Outlook	69
	Regulatory Matters	74
	Accounting Matters	75
	Effects of Inflation and Changing Prices	77
Item 7A.	Quantitative and Qualitative Disclosures About Market Risk	78
Item 8.	Financial Statements and Supplementary Data	83
	Selected Quarterly Information	173
Item 9.	Changes in and Disagreements with Accountants on Accounting and Financial Disclosure	173
Item 9A.	Controls and Procedures	173
Item 9B.	Other Information	174

PART III
Item 10.	Directors, Executive Officers and Corporate Governance	174
Item 11.	Executive Compensation	175
Item 12.	Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters	175
Item 13.	Certain Relationships and Related Transactions and Director Independence	175
Item 14.	Principal Accounting Fees and Services	176

PART IV
Item 15.	Exhibits and Financial Statement Schedules	176
SIGNATURES		181
EXHIBIT INDEX		184

~~OMISSION~~This OFreport ~~CERTAIN~~contains ~~INFORMATION~~“forward-looking” statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended. Forward-looking statements should be read with the cautionary statements and important factors included on pages 4 and 5 of this report under the heading “Forward-looking Statements.” Forward-looking statements are all statements other than statements of historical fact, including those statements that are identified by the use of the words “anticipates,” “estimates,” “expects,” “intends,” “plans,” “predicts,” “projects,” and similar expressions.

~~Ameren~~Table ~~Energy Generating Company meets the conditions set forth in General Instruction I(1)(a) and (b)~~ of ~~Form 10-K and is therefore filing this form with the reduced disclosure format allowed under that General Instruction.~~ Contents

~~This~~GLOSSARY ~~combined~~OF ~~Form~~TERMS ~~10-K~~AND is separately filed by Ameren Corporation, Union Electric Company, Ameren Illinois Company and Ameren Energy Generating Company. Each registrant hereto is filing on its own behalf all of the information contained in this annual report that relates to such registrant. Each registrant hereto is not filing any information that does not relate to such registrant, and therefore makes no representation as to any such information. ABBREVIATIONS

~~Table~~We use the words “our,” “we” or “us” with respect to certain information that relates to all Ameren Companies, as defined below. When appropriate, subsidiaries of ~~Contents~~Ameren are named specifically as we discuss their various business activities.

~~TABLE~~2007 OFIllinois ~~CONTENTS~~Electric Settlement Agreement - A comprehensive settlement of issues in Illinois arising out of the end of ten years of frozen electric rates. The settlement, which became effective in 2007, was designed to avoid rate rollback and freeze legislation and legislation that would have imposed a tax on electric generation in Illinois. The settlement addressed the issue of power procurement.

		Page
GLOSSARY OF TERMS AND ABBREVIATIONS			1
Forward-looking Statements			4
PART I
Item 1.	Business		5
	General		5
	Business Segments		6
	Rates and Regulation		6
	Transmission and Supply of Electric Power		10
	Power Generation		11
	Natural Gas Supply for Distribution		14
	Industry Issues		14
	Operating Statistics		15
	Available Information		17
Item 1A.	Risk Factors		17
Item 1B.	Unresolved Staff Comments		24
Item 2.	Properties		24
Item 3.	Legal Proceedings		26
Item 4.	Mine Safety Disclosures		27
Executive Officers of the Registrants (Item 401(b) of Regulation S-K)			27
PART II
Item 5.	Market for Registrants’ Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities		29
Item 6.	Selected Financial Data.		31
Item 7.	Management’s Discussion and Analysis of Financial Condition and Results of Operations		32
	Overview		32
	Results of Operations		34
	Liquidity and Capital Resources		51
	Outlook		66
	Regulatory Matters		70
	Accounting Matters		70
	Effects of Inflation and Changing Prices		72
Item 7A.	Quantitative and Qualitative Disclosures About Market Risk		73
Item 8.	Financial Statements and Supplementary Data		79
	Selected Quarterly Information		168
Item 9.	Changes in and Disagreements with Accountants on Accounting and Financial Disclosure		169
Item 9A.	Controls and Procedures		169
Item 9B.	Other Information		170
PART III
Item 10.	Directors, Executive Officers and Corporate Governance		170
Item 11.	Executive Compensation		171
Item 12.	Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters		171
Item 13.	Certain Relationships and Related Transactions and Director Independence		172
Item 14.	Principal Accounting Fees and Services		172
PART IV
Item 15.	Exhibits and Financial Statement Schedules		172
SIGNATURES			177
EXHIBIT INDEX			181

2010 Credit Agreements - The 2010 Genco Credit Agreement, the 2010 Illinois Credit Agreement, and the 2010 Missouri Credit Agreement, collectively, which terminated on November 14, 2012.

~~This~~2010 ~~report~~Genco ~~contains~~Credit ~~“forward-looking”~~Agreement ~~statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended. Forward~~-~~looking~~ ~~statements~~Ameren’s ~~should be read with the cautionary statements~~ and ~~important~~Genco’s ~~factors~~$500 ~~included~~million onmultiyear ~~pages~~senior 4unsecured ~~and~~credit ~~5 of this report under the heading “Forward-looking Statements.” Forward-looking statements are all statements other than statements of historical fact~~agreement, ~~including~~which ~~those~~was ~~statements~~terminated ~~that~~on ~~are~~November ~~identified by the use of the words “anticipates~~14,” ~~“estimates,” “expects,” “intends,” “plans,” “predicts,” “projects,” and similar expressions~~2012.

~~Table~~2010 ofIllinois ~~Contents~~Credit Agreement - Ameren’s and Ameren Illinois’ $800 million multiyear senior unsecured credit agreement, which was terminated on November 14, 2012.

~~GLOSSARY~~2010 OFMissouri ~~TERMS~~Credit ~~AND~~Agreement ~~ABBREVIATIONS~~- Ameren’s and Ameren Missouri’s $800 million multiyear senior unsecured credit agreement, which was terminated on November 14, 2012.

We2012 ~~use~~Credit ~~the~~Agreements ~~words~~- ~~“our,”~~The ~~“we”~~2012 orIllinois ~~“us”~~Credit ~~with~~Agreement ~~respect~~and tothe ~~certain~~2012 ~~information~~Missouri ~~that~~Credit ~~relates to all Ameren Companies~~Agreement, ~~as defined below~~collectively. ~~When appropriate, subsidiaries of Ameren are named specifically as we discuss their various business activities.~~

~~2007~~2012 Illinois ~~Electric~~Credit ~~Settlement~~ Agreement –- AAmeren's ~~comprehensive~~and ~~settlement~~Ameren ~~of issues in~~ Illinois' ~~arising~~$1.1 ~~out~~billion ofmultiyear ~~the~~senior ~~end~~unsecured ofcredit ~~ten years of frozen electric rates~~agreement, ~~effective January 2, 2007. The settlement,~~ which ~~became~~expires ~~effective in 2007, was designed to avoid new rate rollback and freeze legislation and legislation that would impose a tax~~ on ~~electric~~November ~~generation in Illinois. The settlement addressed the issue of power procurement~~14, ~~and it included a comprehensive rate relief and customer assistance program~~2017.

~~2010~~2012 Missouri Credit ~~Agreements~~Agreement –- ~~The~~Ameren's ~~2010~~and ~~Genco~~Ameren ~~Credit~~Missouri's ~~Agreement,~~$1 ~~the~~billion ~~2010~~multiyear ~~Illinois~~senior ~~Credit~~unsecured ~~Agreement~~credit agreement, ~~and~~which ~~the~~expires ~~2010~~on ~~Missouri~~November ~~Credit Agreement~~14, ~~collectively~~2017.

~~2010~~AER ~~Genco~~- ~~Credit~~AmerenEnergy ~~Agreement~~Resources –Company, LLC, an Ameren’s ~~and~~Corporation subsidiary that consists of non-rate-regulated operations, including Genco’s, ~~$500~~AERG, ~~million~~Marketing ~~multiyear~~Company ~~senior~~and ~~unsecured~~Medina ~~revolving~~Valley. ~~credit~~The ~~facility~~Medina Valley energy center was sold in February 2012. On October 1, 2010, AERG stock was distributed to Ameren, which ~~expires~~then ~~on September 10~~contributed it to AER, ~~2013.~~thereby making AERG a subsidiary of AER.

AERG - Ameren Energy Resources Generating Company, a CILCO subsidiary until October 1, 2010, that operates a merchant electric generation business in Illinois. ~~Credit~~On ~~Agreement~~October 1, –2010, ~~Ameren’s~~AERG ~~and~~stock was distributed to Ameren ~~Illinois’~~and ~~$800~~subsequently ~~million~~contributed ~~multiyear~~by ~~senior unsecured~~Ameren ~~credit~~to ~~agreement~~AER, which ~~expires~~resulted onin ~~September 10,~~AERG ~~2013.~~becoming a subsidiary of AER.

~~2010~~AFS ~~Missouri~~- ~~Credit~~Ameren ~~Agreement~~Energy –Fuels ~~Ameren’s~~and Services Company, an AER subsidiary that procured fuel and ~~Ameren Missouri’s~~natural ~~$800~~gas ~~million~~and ~~multiyear~~managed ~~senior~~the ~~unsecured~~related ~~revolving~~risks ~~credit~~for ~~facility,~~the ~~which~~Ameren ~~expires~~Companies onprior ~~September~~to January 101, ~~2013~~2011. Effective January 1, 2011, the functions previously performed by AFS were assumed by the Ameren Missouri, Ameren Illinois and Merchant Generation business segments.

~~AER –~~ Ameren ~~Energy~~- ~~Resources Company, LLC, an~~ Ameren Corporation ~~subsidiary~~and ~~that~~its ~~consists~~subsidiaries ofon ~~non-rate-regulated~~a ~~operations,~~consolidated ~~including Genco, AERG, Marketing Company and Medina Valley~~basis. ~~The~~In ~~Medina~~references ~~Valley~~to ~~energy~~financing ~~center~~activities, ~~was~~acquisition ~~sold~~activities, inor ~~February~~liquidity ~~2012. On October 1~~arrangements, ~~2010,~~Ameren ~~AERG~~is ~~stock~~defined ~~was~~as ~~distributed to~~ Ameren, ~~which then contributed it to AER~~Corporation, ~~thereby~~the ~~making AERG a subsidiary of AER~~parent.

~~AERG~~Ameren –Companies ~~AmerenEnergy~~- ~~Resources~~Ameren ~~Generating Company~~Corporation, aAmeren ~~CILCO subsidiary until October 1~~Missouri, ~~2010,~~and ~~that~~Ameren ~~operates a merchant electric generation business in~~ Illinois~~. On October 1~~, ~~2010~~collectively, ~~AERG~~which ~~stock~~are ~~was~~individual ~~distributed~~registrants towithin ~~Ameren~~the ~~and subsequently contributed by~~ Ameren toconsolidated ~~AER, which resulted in AERG becoming a subsidiary of AER~~group.

~~AFS~~Ameren –Illinois ~~Ameren~~or ~~Energy~~AIC ~~Fuels~~- ~~and~~Ameren ~~Services~~Illinois Company, an ~~AER~~Ameren Corporation subsidiary that ~~procured~~operates ~~fuel~~a rate-regulated electric and natural gas transmission and ~~managed~~distribution business in Illinois, doing business as Ameren Illinois. This business consists of the ~~related~~combined ~~risks~~rate-regulated ~~for~~electric and natural gas transmission and distribution businesses operated by CIPS, CILCO and IP before the Ameren ~~Companies~~Illinois Merger. References to Ameren Illinois prior to ~~January 1,~~the ~~2011. Effective~~Ameren ~~January 1,~~Illinois ~~2011,~~Merger refer collectively to the ~~functions~~rate-regulated ~~previously~~electric ~~performed~~and bynatural ~~AFS~~gas ~~were~~transmission ~~assumed~~and bydistribution businesses of CIPS, CILCO and IP. Immediately after the Ameren ~~Missouri~~Illinois Merger, Ameren Illinois distributed the common stock of AERG to Ameren Corporation. AERG’s operating results and ~~Merchant~~cash ~~Generation~~flows ~~business~~prior ~~segments~~to October 1, 2010, were presented as discontinued operations in Ameren Illinois’ financial statements. Ameren Illinois is also defined as a financial reporting segment beginning after 2010.

Ameren –Illinois ~~Ameren~~Merger ~~Corporation~~- ~~and~~On ~~its~~October 1, ~~subsidiaries~~2010, onCILCO aand ~~consolidated~~IP ~~basis.~~merged Inwith ~~references~~and tointo ~~financing activities~~CIPS, ~~acquisition~~with ~~activities,~~the orsurviving ~~liquidity~~corporation ~~arrangements,~~renamed Ameren isIllinois ~~defined as Ameren Corporation, the parent~~Company.

Ameren ~~Companies~~Illinois –Segment ~~The~~- ~~individual~~A ~~registrants~~financial ~~within~~reporting ~~the~~segment consisting of Ameren ~~consolidated~~Illinois’ ~~group.~~rate-regulated businesses.

Ameren ~~Illinois~~Missouri or ~~AIC~~AMO –- ~~Ameren~~Union ~~Illinois~~Electric Company, an Ameren Corporation subsidiary that operates a rate-regulated electric generation, transmission and distribution business, and a rate-regulated natural gas transmission and distribution business in ~~Illinois~~Missouri, doing business as Ameren Missouri. Ameren Missouri is also defined as a financial reporting segment.

~~Illinois.~~Ameren ~~This~~Services ~~business consists of the combined rate~~-~~regulated~~ ~~electric and natural gas transmission and distribution businesses operated by CIPS, CILCO and IP before the~~ Ameren ~~Illinois~~Services ~~Merger. References to Ameren Illinois prior to the Ameren Illinois Merger refer collectively to the rate-regulated electric and natural gas transmission and distribution businesses of CIPS~~Company, ~~CILCO~~an ~~and IP. Immediately after the~~ Ameren ~~Illinois~~Corporation ~~Merger,~~subsidiary ~~Ameren Illinois~~that ~~distributed~~provides ~~the~~support ~~common~~services ~~stock of AERG~~ to Ameren ~~Corporation. AERG’s operating results~~ and ~~cash~~its ~~flows were presented as discontinued operations in Ameren Illinois’ financial statements~~subsidiaries.

~~Ameren~~AMIL ~~Illinois~~- ~~Merger~~The –MISO Onbalancing ~~October 1,~~authority ~~2010~~area operated by Ameren, ~~CILCO~~which ~~and~~includes IPthe ~~merged~~load ~~with~~of Ameren Illinois and ~~into~~the ~~CIPS,~~Merchant ~~with~~Generation ~~the~~energy ~~surviving~~centers ~~corporation~~(excluding ~~renamed~~EEI ~~Ameren~~and ~~Illinois Company.~~Elgin CT energy centers).

~~Ameren~~AMMO ~~Illinois~~- ~~Regulated~~The ~~Segment~~MISO –balancing Aauthority ~~financial~~area ~~reporting~~operated ~~segment~~by ~~consisting~~Ameren, which includes the load and generation energy centers of Ameren ~~Illinois’ rate-regulated businesses~~Missouri.

~~Ameren~~ARO ~~Missouri or AMO – Union Electric Company, an Ameren Corporation subsidiary that operates a rate~~-~~regulated~~ ~~electric generation,~~Asset ~~transmission~~retirement ~~and distribution business, and a rate-regulated natural gas transmission and distribution business in Missouri, doing business as Ameren Missouri~~obligations. ~~Ameren Missouri is also defined as a financial reporting segment consisting of Union Electric Company’s rate-regulated businesses.~~

~~Ameren~~ATXI ~~Services~~- – Ameren ~~Services~~Transmission Company of Illinois, an Ameren Corporation subsidiary that ~~provides~~is ~~support~~engaged ~~services~~in tothe ~~Ameren~~construction and ~~its~~operation ~~subsidiaries.~~of electric transmission assets.

~~AMIL~~Baseload –- The ~~MISO~~minimum ~~balancing~~amount ~~authority~~of ~~area~~electric ~~operated~~power ~~by Ameren,~~delivered ~~which~~or ~~includes~~required ~~the~~over ~~load~~a ofgiven ~~Ameren~~period ~~Illinois and the generating assets~~ of ~~Genco~~time ~~(excluding~~at ~~EEI~~a ~~and~~steady ~~Genco’s Elgin CT facility) and AERG~~rate.

~~AMMO~~Btu –- ~~The~~British ~~MISO~~thermal ~~balancing~~unit, ~~authority~~a ~~area~~standard ~~operated~~unit byfor ~~Ameren,~~measuring ~~which~~the ~~includes~~quantity of heat energy required to raise the ~~load~~temperature ~~and~~of ~~generating~~one ~~assets~~pound of ~~Ameren~~water ~~Missouri.~~by one degree Fahrenheit.

~~ARO~~CAIR –- ~~Asset~~Clean ~~retirement~~Air ~~obligations.~~Interstate Rule.

~~ATX~~Capacity –factor ~~Ameren~~- ~~Transmission~~A ~~Company,~~percentage measure that indicates how much of an ~~Ameren~~energy ~~Corporation~~center's ~~subsidiary~~capacity ~~dedicated~~was toused ~~electric~~during ~~transmission~~a ~~infrastructure~~specific ~~investment~~period.

~~ATXI~~CCR –- ~~Ameren~~Coal ~~Transmission~~combustion ~~Company of Illinois, an Ameren Corporation subsidiary that is engaged in the construction and operation of electric transmission assets in Illinois~~residuals.

~~Baseload~~CILCO –- ~~The~~Central ~~minimum~~Illinois ~~amount~~Light ofCompany, ~~electric~~a ~~power~~former ~~delivered~~Ameren orCorporation ~~required~~subsidiary ~~over~~that operated a ~~given~~rate-regulated ~~period~~electric ~~of time~~transmission atand distribution business, a ~~steady~~merchant ~~rate.~~electric

~~Btu – British thermal unit, a standard unit for measuring the quantity of heat energy required to raise the temperature of one pound of water by one degree Fahrenheit.~~ 1

~~CAIR~~Table –of ~~Clean Air Interstate Rule.~~ Contents

~~Capacity~~generation ~~factor~~business –through AAERG, ~~percentage~~and ~~measure~~a ~~that~~rate-regulated ~~indicates~~natural ~~how~~gas ~~much~~transmission and distribution business, all in Illinois, before the Ameren Illinois Merger. CILCO owned all of anthe ~~electric~~common ~~power~~stock ~~generating~~of ~~unit’s~~AERG ~~capacity~~and ~~was~~included ~~used~~AERG ~~during~~within aits ~~specific period~~consolidated financial statements. Immediately after the Ameren Illinois Merger in 2010, Ameren Illinois distributed the common stock of AERG to Ameren Corporation. AERG's operating results and cash flows prior to October 1, 2010, were presented as discontinued operations in Ameren Illinois’ financial statements.

1CILCORP - CILCORP Inc., a former Ameren Corporation subsidiary that operated as a holding company for CILCO and its merchant generation subsidiary. On March 4, 2010, CILCORP merged with and into Ameren.

~~Table~~CIPS - Central Illinois Public Service Company, an Ameren Corporation subsidiary, renamed Ameren Illinois Company at the effective date of ~~Contents~~the Ameren Illinois Merger, which operates a rate-regulated electric and natural gas transmission and distribution business, all in Illinois.

~~CCR~~CO2 –- ~~Coal~~Carbon ~~combustion residuals~~dioxide.

~~CILCO~~COL ~~– Central Illinois Light Company, a former Ameren Corporation subsidiary that operated a rate~~-~~regulated~~ ~~electric~~Nuclear ~~transmission~~energy ~~and~~center ~~distribution~~combined ~~business,~~construction ~~a merchant electric generation business through AERG,~~ and aoperating ~~rate-regulated natural gas transmission and distribution business, all in Illinois, before the Ameren Illinois Merger~~license. CILCO owned all of the common stock of AERG and included AERG within its consolidated financial statements. Immediately after the Ameren Illinois Merger in 2010, Ameren Illinois distributed the common stock of AERG to Ameren Corporation. AERG was treated as a discontinued operation within Ameren Illinois’ financial statements.

~~CILCORP~~Cole –County ~~CILCORP~~Circuit ~~Inc.,~~Court a- ~~former~~Circuit ~~Ameren~~Court ~~Corporation~~of ~~subsidiary~~Cole ~~that operated as a holding company for CILCO and its merchant generation subsidiary. On March 4~~County, ~~2010, CILCORP merged with and into Ameren~~Missouri.

~~CIPS~~Cooling –degree-days ~~Central~~- ~~Illinois~~The ~~Public~~summation ~~Service~~of ~~Company,~~positive andifferences ~~Ameren Corporation~~between ~~subsidiary,~~the ~~renamed~~mean ~~Ameren~~daily ~~Illinois~~temperature ~~Company~~and ata ~~the~~65-degree ~~effective~~Fahrenheit ~~date~~base. ofThis ~~the~~statistic ~~Ameren~~is ~~Illinois~~useful ~~Merger,~~as ~~that~~an ~~operates~~indicator aof ~~rate-regulated~~electricity ~~electric~~demand ~~and~~by ~~natural~~residential ~~gas transmission~~ and ~~distribution~~commercial ~~business,~~customers ~~all~~for insummer ~~Illinois~~cooling.

~~CO2~~CSAPR –- ~~Carbon~~Cross-State ~~dioxide.~~Air Pollution Rule.

~~COLA~~CT ~~– Combined~~- ~~nuclear~~Combustion ~~plant~~turbine ~~construction~~electric ~~and~~energy ~~operating~~center ~~license~~used ~~application.~~primarily for peaking capacity.

~~Cole~~DOE ~~County~~- ~~Circuit~~Department ~~Court~~of –Energy, ~~Circuit~~a ~~Court~~United ofStates ~~Cole~~government ~~County, Missouri~~agency.

~~Cooling~~DRPlus ~~degree~~-~~days~~ –Ameren ~~The~~Corporation’s ~~summation~~dividend ofreinvestment ~~positive differences between the mean daily temperature~~ and adirect ~~65-degree~~stock ~~Fahrenheit base.~~purchase ~~This statistic is useful for estimating electricity demand by residential and commercial customers for summer cooling~~plan.

~~CSAPR~~Dekatherm ~~– Cross~~-~~State~~ ~~Air~~One ~~Pollution~~million ~~Rule.~~Btus of natural gas.

CTEEI –- ~~Combustion~~Electric ~~turbine~~Energy, Inc., an 80%-owned Genco subsidiary that operates merchant electric generation ~~equipment~~energy ~~used~~centers ~~primarily~~and ~~for~~FERC-regulated ~~peaking~~transmission ~~capacity~~facilities in Illinois. The remaining 20% ownership interest is owned by Kentucky Utilities Company, a nonaffiliated entity.

~~DOE~~Entergy –- ~~Department~~Entergy ~~of Energy~~Arkansas, ~~a United States government agency~~Inc.

~~DRPlus~~EPA –- ~~Ameren~~Environmental ~~Corporation’s~~Protection ~~dividend~~Agency, ~~reinvestment~~a ~~and~~United ~~direct~~States ~~stock~~government ~~purchase plan~~agency.

~~Dth (dekatherm)~~Equivalent –availability ~~One~~factor ~~million~~- ~~Btus~~A measure that indicates the percentage of ~~natural~~time ~~gas.~~an energy center was available for service during a period.

~~EEI~~ERISA ~~– Electric Energy, Inc., an 80%~~-~~owned~~ ~~Genco~~Employee ~~subsidiary~~Retirement ~~that~~Income ~~operates merchant~~Security ~~electric~~Act ~~generation~~of ~~facilities and FERC-regulated transmission facilities in Illinois. Effective January 1~~1974, ~~2010,~~as ~~in an internal reorganization, AER contributed its 80% ownership interest in EEI to its subsidiary, Genco~~amended. ~~The remaining 20% ownership interest is owned by Kentucky Utilities Company, a nonaffiliated entity.~~

~~EPA~~Exchange –Act ~~Environmental~~- ~~Protection~~Securities ~~Agency,~~Exchange aAct ~~U.S. government~~of ~~agency.~~1934, as amended.

~~Equivalent~~FAC ~~availability~~- ~~factor~~A –fuel Aand ~~measure~~purchased power cost recovery mechanism that ~~indicates~~allows ~~the~~Ameren ~~percentage~~Missouri to recover, through customer rates, 95% of ~~time~~changes anin ~~electric~~fuel ~~power~~(coal, ~~generating~~coal ~~unit was~~transportation, ~~available~~natural gas for ~~service~~generation, ~~during~~and nuclear), certain fuel additives, emission allowances, purchased power costs, transmission costs and MISO costs and revenues, net of off-system revenues, greater or less than the amount set in base rates without a ~~period~~traditional rate proceeding, subject to MoPSC prudency reviews. The MoPSC's December 2012 electric rate order changed the FAC to include activated carbon, limestone and urea costs, along with

~~ERISA~~transmission ~~– Employee Retirement Income Security Act of 1974~~revenues, asstarting ~~amended.~~in 2013.

~~Exchange~~FASB ~~Act~~- –Financial ~~Securities~~Accounting ~~Exchange~~Standards ~~Act~~Board, ofa ~~1934,~~rulemaking asorganization ~~amended.~~that establishes financial accounting and reporting standards in the United States.

~~FAC~~FERC –- AFederal ~~fuel~~Energy ~~and~~Regulatory ~~purchased~~Commission, ~~power~~a ~~cost~~United ~~recovery~~States ~~mechanism~~government ~~that allows Ameren Missouri to recover,~~ agency.

~~through~~Fitch ~~customer rates, 95% of changes in fuel (coal, coal transportation, natural gas for generation, and nuclear), emission allowances and purchased power costs, net of off~~-~~system~~ ~~revenues, including~~Fitch ~~MISO costs and revenues~~Ratings, ~~greater or less than the amount set in base rates, without~~ a ~~traditional~~credit ~~rate~~rating ~~proceeding~~agency.

~~FASB~~FTRs – - Financial ~~Accounting~~transmission ~~Standards Board~~rights, afinancial ~~rulemaking~~instruments ~~organization~~ that ~~establishes~~entitle ~~financial~~the ~~accounting~~holder ~~and~~to ~~reporting~~pay ~~standards~~or inreceive ~~the~~compensation ~~United~~for ~~States.~~certain congestion-related transmission charges between two designated points.

~~FERC~~Fuelco –- Fuelco LLC, a limited liability company that provides nuclear fuel management and services to its members. The ~~Federal~~members ~~Energy~~are ~~Regulatory~~Ameren ~~Commission~~Missouri, aLuminant, ~~United~~and ~~States~~Pacific ~~government~~Gas ~~agency.~~and Electric Company.

~~Fitch~~GAAP –- ~~Fitch~~Generally ~~Ratings,~~accepted aaccounting ~~credit~~principles ~~rating~~in ~~agency.~~the United States of America.

~~FTRs~~Genco –- ~~Financial~~Ameren ~~transmission rights~~Energy Generating Company, ~~financial~~an ~~instruments~~AER subsidiary that ~~entitle~~operates ~~the~~a ~~holder~~merchant toelectric ~~pay~~generation orbusiness ~~receive~~in ~~compensation~~Illinois ~~for~~and ~~certain~~holds ~~congestion-related~~an ~~transmission~~80% ~~charges~~ownership ~~between~~interest ~~two~~in ~~designated points~~EEI.

~~Fuelco~~Heating –degree-days ~~Fuelco~~- ~~LLC,~~The asummation ~~limited~~of ~~liability~~negative ~~company~~differences ~~that~~between ~~provides~~the ~~nuclear~~mean ~~fuel~~daily ~~management~~temperature and ~~services~~a to65-degree ~~its~~Fahrenheit ~~members~~base. ~~The~~This ~~members~~statistic ~~are~~is ~~Ameren~~useful ~~Missouri,~~as ~~Luminant,~~an indicator of demand for electricity and ~~Pacific~~natural ~~Gas~~gas for winter space heating by residential and ~~Electric Company.~~commercial customers.

~~GAAP~~IBEW –- ~~Generally~~International ~~accepted~~Brotherhood ~~accounting~~of ~~principles~~Electrical inWorkers, ~~the~~a ~~United~~labor ~~States of America~~union.

~~Genco~~ICC –- ~~Ameren~~Illinois ~~Energy~~Commerce ~~Generating Company~~Commission, ana ~~AER~~state ~~subsidiary~~agency that ~~operates~~regulates aIllinois ~~merchant~~utility ~~electric~~businesses, ~~generation~~including ~~business~~Ameren in Illinois and ~~holds an 80% ownership interest in EEI~~ATXI.

~~Gigawatthour~~IEIMA –- ~~One~~Illinois ~~thousand~~Energy ~~megawatthours~~Infrastructure Modernization Act, an Illinois law that established a performance-based formula process for determining electric delivery service rates. Ameren Illinois elected to participate in this regulatory framework in 2012, which will require it to make incremental capital expenditures to modernize its electric distribution system over a ten-year period, to meet performance standards, and to create jobs in Illinois, among other things.

~~Heating~~Illinois ~~degree-days~~Customer –Choice ~~The~~Law ~~summation~~- ofIllinois ~~negative~~Electric ~~differences~~Service ~~between~~Customer ~~the~~Choice ~~mean~~and ~~daily~~Rate ~~temperature~~Relief ~~and~~Law aof ~~65-~~1997, ~~degree~~which ~~Fahrenheit~~was ~~base.~~designed ~~This~~to ~~statistic~~introduce iscompetition ~~useful~~into asthe anretail ~~indicator~~supply of ~~demand~~electric ~~for~~energy ~~electricity and~~in ~~natural gas for winter space heating by residential and commercial customers~~Illinois.

~~IBEW~~IP –- ~~International~~Illinois ~~Brotherhood~~Power ~~of Electrical Workers~~Company, a ~~labor~~former ~~union.~~Ameren Corporation subsidiary that operated a rate-regulated electric and natural gas transmission and distribution business, all in Illinois, before the Ameren Illinois Merger.

~~ICC~~IPA –- Illinois ~~Commerce~~Power ~~Commission~~Agency, a state government agency that ~~regulates~~has ~~Illinois~~broad ~~utility~~authority ~~businesses,~~to ~~including~~assist ~~ATXI~~ in the procurement of electric power for residential and ~~Ameren~~small ~~Illinois.~~commercial customers.

~~IEIMA~~ISRS –- ~~Illinois Energy~~ Infrastructure ~~Modernization~~system ~~Act~~replacement surcharge, anwhich ~~Illinois~~is ~~law that established~~ a ~~performance-based formula~~cost ~~process~~recovery ~~for~~mechanism ~~determining~~that ~~electric~~allows ~~delivery service rates.~~ Ameren ~~Illinois~~Missouri ~~elected~~ to ~~participate~~recover innatural ~~this~~gas ~~regulatory~~infrastructure ~~framework~~replacement incosts ~~2012,~~from ~~which~~utility ~~will~~customers ~~require~~without ~~it to make incremental capital expenditures to modernize its electric distribution system over~~ a ~~ten-year~~traditional ~~period~~rate ~~beginning in 2012, to meet performance standards, and to create jobs in Illinois, among other things~~proceeding.

~~Illinois Customer~~IUOE ~~Choice~~- ~~Law~~International –Union ~~Illinois Electric Service Customer Choice and Rate Relief Law~~ of ~~1997~~Operating Engineers, ~~which~~a ~~was~~labor ~~designed to introduce competition into the retail supply of electric energy in Illinois~~union.

~~Illinois~~Kilowatthour ~~EPA~~- –A ~~Illinois~~measure ~~Environmental~~of ~~Protection~~electricity ~~Agency~~consumption equivalent to the use of 1,000 awatts ~~state~~of ~~government~~power ~~agency.~~over one hour.

IPLIUNA ~~– Illinois Power Company, a former Ameren Corporation subsidiary that operated a rate~~-~~regulated~~ ~~electric~~Laborers’ ~~and~~International ~~natural~~Union ~~gas~~of ~~transmission~~North ~~and distribution business~~America, ~~all~~a inlabor ~~Illinois, before the Ameren Illinois Merger~~union.

~~IPA – Illinois Power Agency, a state government agency that has broad authority to assist in the procurement of electric power for residential and nonresidential customers.~~ 2

2Table of Contents

~~Table~~Marketing ofCompany ~~Contents~~- Ameren Energy Marketing Company, an AER subsidiary that markets power for Genco, AERG, and EEI.

~~ISRS~~MATS –- ~~Infrastructure~~Mercury ~~system~~and ~~replacement~~Air ~~surcharge,~~Toxics ~~which is a cost recovery mechanism that allows Ameren Missouri to recover gas infrastructure replacement costs from utility customers without a traditional rate proceeding~~Standards.

~~IUOE~~Medina ~~– International~~Valley ~~Union~~- ofAmeren ~~Operating~~Energy ~~Engineers~~Medina Valley Cogen LLC, an AER subsidiary, which owned a ~~labor~~40-megawatt ~~union~~natural gas-fired electric energy center. This energy center was sold in February 2012.

~~Kilowatthour~~MEEIA –-- AMissouri ~~measure~~Energy ofEfficiency ~~electricity~~Investment ~~consumption~~Act, ~~equivalent~~a toMissouri ~~the~~law ~~use of~~that ~~1,000~~allows ~~watts~~electric ofutilities ~~power~~to ~~over~~recover ~~one~~costs ~~hour.~~related to MoPSC-approved energy efficiency programs.

~~LIUNA~~Megawatthour –or ~~Laborers’~~MWh ~~International~~- ~~Union~~One ofthousand ~~North America, a labor union~~kilowatthours.

~~Marketing~~Merchant ~~Company~~Generation –- ~~Ameren~~A ~~Energy~~financial ~~Marketing~~reporting ~~Company,~~segment anconsisting ~~AER~~primarily ~~subsidiary~~of ~~that~~the ~~markets~~operations ~~power~~of ~~for~~AER, including Genco, AERG, ~~EEI~~Medina Valley and ~~Medina~~Marketing ~~Valley~~Company.

~~MATS~~MGP –- ~~Mercury~~Manufactured ~~and~~gas ~~Air Toxics Standards, issued by the EPA on December 21, 2011, which limit mercury, acid gases and other toxic pollution from power plants~~plant.

~~Medina~~MIEC ~~Valley – AmerenEnergy Medina Valley Cogen LLC, an AER subsidiary, which owns a 40~~-~~megawatt natural~~ ~~gas-fired~~Missouri ~~electric~~Industrial ~~energy~~Energy ~~center~~Consumers. ~~This energy center was sold in February 2012.~~

~~MEEIA~~MISO –- ~~Missouri~~Midwest ~~Energy~~Independent ~~Efficiency~~Transmission ~~Investment Act~~System Operator, aInc., ~~Missouri~~an ~~law that allows electric utilities to recover costs related to MoPSC-approved energy efficiency programs~~RTO.

~~Megawatthour –~~MISO ~~One~~Energy ~~thousand~~and ~~kilowatthours.~~Operating Reserves Market - A market that uses market-based pricing, which takes into account transmission congestion and line losses, to compensate market participants for power and ancillary services.

~~Merchant~~Missouri ~~Generation~~Environmental –Authority A- ~~financial~~Environmental ~~reporting~~Improvement ~~segment~~and ~~consisting~~Energy ~~primarily~~Resources Authority of the ~~operations~~state ~~or activities~~ of ~~AER~~Missouri, ~~including~~a ~~Genco,~~governmental ~~AERG,~~body ~~Medina~~authorized ~~Valley~~to ~~and~~finance ~~Marketing~~environmental ~~Company.~~projects by issuing tax-exempt bonds and notes.

~~MGP~~Mmbtu –- ~~Manufactured~~One ~~gas~~million ~~plant~~Btus.

~~MIEC~~Money –pool ~~Missouri~~- ~~Industrial~~Borrowing ~~Energy~~agreements ~~Consumers~~among Ameren and its subsidiaries to coordinate and provide for certain short-term cash and working capital requirements. Separate money pools maintained for rate-regulated and non-rate-regulated businesses are referred to as the utility money pool and the non-state-regulated subsidiary money pool, respectively.

~~MISO~~Moody’s –- ~~Midwest~~Moody’s ~~Independent~~Investors ~~Transmission~~Service ~~System Operator,~~ Inc., ana ~~RTO.~~credit rating agency.

~~MISO~~MoOPC ~~Energy and Operating Reserves Market – A market that uses market~~-~~based~~ ~~pricing,~~Missouri ~~which~~Office ~~takes~~of ~~into~~Public ~~account transmission congestion and line losses, to compensate market participants for power and ancillary services~~Counsel.

~~Missouri~~MoPSC ~~Environmental~~- ~~Authority~~Missouri –Public ~~Environmental~~Service ~~Improvement and Energy Resources Authority of the state of Missouri~~Commission, a ~~governmental~~state ~~body~~agency ~~authorized~~that toregulates ~~finance~~Missouri ~~environmental~~utility ~~projects~~businesses byincluding ~~issuing~~Ameren ~~tax-exempt bonds and notes~~Missouri.

~~Mmbtu~~MPS –- ~~One~~Multi-Pollutant ~~million Btus.~~Standard, a compliance alternative within Illinois law covering reductions in emissions of SO2, NOx, and mercury, which Genco, EEI, and AERG elected in 2006.

~~Money~~MTM ~~pool – Borrowing agreements among Ameren and its subsidiaries to coordinate and provide for certain short~~-~~term~~ ~~cash and working capital requirements. Separate money pools maintained for rate~~Mark-~~regulated and non-rate-regulated businesses are referred~~ to ~~as the utility money pool and the non~~-~~state-regulated subsidiary money pool, respectively~~market.

~~Moody’s~~MW –- ~~Moody’s Investors Service Inc~~Megawatt.~~, a credit rating agency.~~

~~MoOPC~~Native –load ~~Missouri~~- ~~Office~~End-use ofretail ~~Public~~customers ~~Counsel~~whom we are obligated to serve by statute, franchise, contract, or other regulatory requirement.

~~MoPSC~~NERC –- ~~Missouri~~North ~~Public~~American ~~Service~~Electric ~~Commission,~~Reliability ~~a state agency that regulates Missouri utility businesses including Ameren Missouri~~Corporation.

~~MPS~~NO2 ~~– Multi~~-~~Pollutant~~ ~~Standard,~~Nitrogen ~~an agreement, as amended, reached in 2006 among Genco, AERG, EEI and the Illinois EPA, which was codified in Illinois environmental regulations~~dioxide.

~~MTM~~NOx ~~– Mark~~-~~to-market.~~ Nitrogen oxide.

MWNoranda –- ~~Megawatt.~~Noranda Aluminum, Inc.

~~Native~~NPNS ~~load – End~~-~~use~~ ~~retail~~Normal ~~customers~~purchases ~~whom~~and wenormal ~~are obligated to serve by statute, franchise, contract, or other regulatory requirement~~sales.

~~NERC~~NRC ~~– North~~- ~~American~~Nuclear ~~Electric~~Regulatory ~~Reliability~~Commission, ~~Corporation.~~a United States government agency.

~~NO2~~NSPS –- ~~Nitrogen~~New ~~dioxide.~~Source Performance Standards, a provision under the Clean Air Act.

~~NOx~~NSR –- ~~Nitrogen~~New ~~oxide.~~Source Review provisions of the Clean Air Act, which include Nonattainment New Source Review and Prevention of Significant Deterioration regulations.

~~Noranda~~NWPA ~~– Noranda~~- ~~Aluminum~~Nuclear Waste Policy Act of 1982, ~~Inc.~~as amended.

~~NPNS~~NYMEX –- ~~Normal~~New ~~purchases~~York ~~and~~Mercantile ~~normal sales~~Exchange.

~~NRC~~NYSE –- ~~Nuclear~~New ~~Regulatory~~York ~~Commission~~Stock Exchange, ~~a United States government agency~~Inc.

~~NSPS~~OATT ~~– New~~- ~~Source~~Open ~~Performance~~Access ~~Standards,~~Transmission ~~a provision under the Clean Air Act~~Tariff.

~~NSR~~OCI –- ~~New~~Other ~~Source~~comprehensive ~~Review~~income ~~provisions~~(loss) ofas ~~the~~defined ~~Clean~~by ~~Air Act, which include Nonattainment New Source Review and Prevention of Significant Deterioration regulations~~GAAP.

~~NWPA~~Off-system –revenues ~~Nuclear~~- ~~Waste~~Revenues ~~Policy~~from ~~Act~~other ~~of 1982~~than native load sales, asincluding ~~amended.~~wholesale sales beginning with the effective date of the MoPSC’s 2011 electric rate order.

~~NYMEX~~OTC –- ~~New York Mercantile Exchange~~Over-the-counter.

~~NYSE~~PGA –- ~~New~~Purchased ~~York~~Gas ~~Stock~~Adjustment ~~Exchange~~tariffs, ~~Inc.~~which permit prudently incurred natural gas costs to be recovered directly from utility customers without a traditional rate proceeding.

~~OATT~~PJM –- ~~Open~~PJM ~~Access~~Interconnection ~~Transmission Tariff~~LLC.

~~OCI~~PUHCA –2005 ~~Other~~- ~~comprehensive~~The ~~income~~Public ~~(loss)~~Utility asHolding ~~defined~~Company byAct ~~GAAP.~~of 2005.

~~Off~~Regulatory lag -~~system~~ ~~revenues~~The –effect ~~Revenues~~of ~~from~~adjustments ~~other~~to ~~than~~retail ~~native~~electric ~~load~~and ~~sales,~~natural ~~including~~gas ~~wholesale~~rates ~~sales~~being ~~beginning~~based ~~with~~on ~~the~~historic ~~effective~~cost ~~date~~and ofrevenue levels. Rate increase requests can take up to 11 months to be acted upon by the MoPSC’s ~~2011~~and ~~electric~~the ~~rate order~~ICC. As a result, revenue increases authorized by regulators will lag behind changing costs and revenues when based on historical periods.

~~OTC~~Revenue –requirement ~~Over~~- The cost of providing utility service to customers, which is calculated as the~~-counter.~~ sum of a utility's recoverable operating and maintenance expenses, depreciation and amortization expense, taxes and an allowed return on investment.

~~PGA~~RFP ~~– Purchased~~- ~~Gas~~Request ~~Adjustment~~for ~~tariffs, which permit prudently incurred natural gas costs to be recovered directly from utility customers without a traditional rate proceeding~~proposal.

~~PJM~~RTO –- ~~PJM~~Regional ~~Interconnection~~Transmission ~~LLC~~Organization.

~~PUHCA~~S&P ~~2005~~- –Standard & ~~The~~Poor’s ~~Public~~Ratings ~~Utility Holding Company Act of 2005~~Services, ~~enacted~~a ascredit ~~part~~rating ~~of the Energy Policy Act of 2005, effective February 8, 2006~~agency.

~~Regulatory~~SEC ~~lag~~- –Securities ~~The effect of adjustments to retail electric~~ and ~~natural~~Exchange ~~gas~~Commission, ~~rates being based on historic cost and revenue levels. Rate increase requests can take up to 11 months to be acted upon by the MoPSC and the ICC. As~~ a ~~result,~~United States ~~revenue~~government ~~increases authorized by regulators will lag behind changing costs and revenues when based on historical periods~~agency.

~~RFP~~SERC –- ~~Request~~SERC Reliability Corporation, one of the regional electric reliability councils organized for ~~proposal.~~coordinating the planning and operation of the nation’s bulk power supply.

~~RTO~~SO2 –- ~~Regional~~Sulfur ~~Transmission Organization~~dioxide.

~~S&P~~Stoddard –County ~~Standard &~~Circuit ~~Poor’s~~Court ~~Ratings~~- ~~Services,~~Circuit aCourt ~~credit~~of ~~rating~~Stoddard ~~agency.~~County, Missouri.

~~SEC~~UA –- ~~Securities~~United ~~and~~Association ~~Exchange~~of ~~Commission~~Plumbers and Pipefitters, a ~~United States~~labor ~~government agency~~union.

3Westinghouse - Westinghouse Electric Company.

~~Table~~FORWARD-LOOKING ~~of Contents~~STATEMENTS

~~SERC~~Statements –in ~~SERC~~this ~~Reliability~~report ~~Corporation~~not based on historical facts are considered “forward-looking” and, ~~one~~accordingly, ofinvolve ~~the~~risks ~~regional~~and ~~electric~~uncertainties ~~reliability~~that ~~councils~~could ~~organized for~~cause ~~coordinating~~actual results to differ materially from those discussed. Although such forward-looking statements have been made in good faith and are based on reasonable assumptions, there is no assurance that the ~~planning~~expected results will be achieved. These statements include (without limitation) statements as to future expectations, beliefs, plans, strategies, objectives, events, conditions, and ~~operation~~financial performance. In connection with the “safe harbor” provisions of the ~~nation’s~~Private ~~bulk~~Securities ~~power~~Litigation ~~supply~~Reform Act of 1995, we are providing this cautionary statement to identify important factors that could cause actual results to differ materially from those anticipated.

~~SO2 – Sulfur dioxide.~~ 3

UATable ~~– United Association~~ of ~~Plumbers and Pipefitters, a labor union.~~ Contents

~~UGSOA~~The –following ~~United~~factors, ~~Government~~in ~~Security~~addition ~~Officers~~to ofthose ~~America~~discussed under Risk Factors and elsewhere in this report and in our other filings with the SEC, acould ~~labor~~cause ~~union.~~ actual results to differ materially from management expectations suggested in such forward-looking statements:

~~FORWARD-LOOKING~~• ~~STATEMENTS~~regulatory, judicial, or legislative actions, including changes in regulatory policies and ratemaking determinations, such as the outcome of Ameren Illinois' natural gas rate case filed in 2013; the court appeals of Ameren Missouri's and Ameren Illinois' electric rate orders issued in 2012; Ameren Missouri's FAC prudence review and the related request for an accounting authority order; Ameren Illinois' request for rehearing of a July 2012 FERC order regarding the inclusion of acquisition premiums in Ameren Illinois transmission rates; and future regulatory, judicial, or legislative actions that seek to change regulatory recovery mechanisms;

~~Statements~~• inthe ~~this~~effect ~~report~~of ~~not~~Ameren ~~based~~Illinois ~~on historical~~participating ~~facts~~in ~~are~~a ~~considered “forward~~performance-~~looking”~~based ~~and,~~formula ~~accordingly,~~ratemaking ~~involve~~process ~~risks~~under ~~and~~the ~~uncertainties that could cause actual results to differ materially from those discussed. Although such forward-looking statements have been made in good faith and are based on reasonable assumptions~~IEIMA, ~~there is no assurance that~~ the ~~expected~~related ~~results~~financial ~~will~~commitments berequired ~~achieved.~~by ~~These~~the ~~statements include (without limitation) statements as to future expectations~~IEIMA, ~~beliefs, plans, strategies, objectives, events, conditions,~~ and ~~financial performance. In connection with~~ the ~~“safe~~resulting ~~harbor”~~uncertain ~~provisions~~impact ofon the ~~Private~~financial ~~Securities Litigation Reform Act of 1995~~condition, ~~we are providing this cautionary statement to identify important factors that could cause actual~~ results toof ~~differ~~operations ~~materially from those anticipated. The following factors, in addition to those discussed under Risk Factors~~ and ~~elsewhere~~liquidity inof ~~this~~Ameren ~~report and in our other filings with the SEC, could cause actual results to differ materially from management expectations suggested in such forward-looking statements:~~ Illinois;

Ÿ• ~~regulatory, judicial, or legislative actions, including changes in regulatory policies and ratemaking determinations, such as the outcome of~~ Ameren ~~Missouri’~~'s ~~and~~eventual ~~Ameren~~exit ~~Illinois’~~from ~~electric rate cases filed in 2012;~~ the ~~Ameren~~Merchant ~~Illinois’~~Generation ~~natural~~business ~~gas~~could ~~rate~~result ~~order issued~~ in ~~2012;~~impairments ~~the~~of ~~court~~long-lived ~~appeals~~assets, disposal-related tolosses, ~~Ameren~~contingencies, ~~Missouri’s~~reduction ~~2010~~of ~~and~~existing ~~2011~~deferred ~~electric~~tax ~~rate orders; Ameren Illinois’ 2010 electric and natural gas rate order; Ameren Missouri’s FAC prudence review; and future regulatory~~assets, ~~judicial,~~ or ~~legislative~~could ~~actions~~have ~~that~~other ~~seek~~adverse toimpacts ~~change~~on ~~regulatory~~the ~~recovery~~financial ~~mechanisms~~condition, ~~such~~results asof ~~the~~operations ~~recent~~and ~~passage~~liquidity of ~~legislation providing for formula ratemaking in Illinois~~Ameren;

Ÿ• the ~~effect~~effects of, ~~Ameren~~or ~~Illinois~~changes ~~participating in a new performance-based formula ratemaking process under the IEIMA~~to, the ~~related~~Illinois ~~financial~~power ~~commitments~~procurement ~~required by the IEIMA and the resulting uncertain impact on the financial condition, results of operations and liquidity of Ameren Illinois~~process;

Ÿ• ~~the~~changes ~~effects~~in ~~of,~~laws orand ~~changes~~other togovernmental actions, ~~the~~including ~~Illinois~~monetary, ~~power~~fiscal, ~~procurement~~and ~~process~~tax policies;

Ÿ• changes in laws or regulations that adversely affect the ability of electric distribution companies and other ~~governmental~~purchasers ~~actions~~of wholesale electricity to pay their suppliers, including ~~monetary,~~Ameren ~~fiscal,~~Missouri and ~~tax~~Marketing ~~policies~~Company;

Ÿ• ~~changes~~the ineffects ~~laws~~of orincreased ~~regulations~~competition ~~that~~in ~~adversely~~the ~~affect~~future ~~the~~due ~~ability~~to, ofamong ~~electric~~other ~~distribution~~things, ~~companies~~deregulation ~~and~~of ~~other~~certain ~~purchasers~~aspects of ~~wholesale~~our ~~electricity~~business toat ~~pay~~both ~~their~~the ~~suppliers,~~state ~~including~~and ~~Ameren~~federal ~~Missouri~~levels, and ~~Marketing~~the ~~Company~~implementation of deregulation;

Ÿ• the effects ofon ~~increased~~demand ~~competition~~for inour ~~the~~services ~~future~~resulting ~~due~~from ~~to,~~technological ~~among other things~~advances, ~~deregulation~~including ofadvances ~~certain~~in ~~aspects~~energy ofefficiency ~~our business at both the state~~ and ~~federal~~distributed ~~levels,~~generation ~~and the implementation of deregulation~~sources, ~~such~~which asgenerate ~~occurred~~electricity ~~when the electric rate freeze and power supply contracts expired in Illinois~~ at the ~~end~~site of ~~2006~~consumption;

Ÿ• ~~the~~increasing ~~effects~~capital onexpenditure ~~demand~~and ~~for~~operating ~~our~~expense ~~services~~requirements ~~resulting from technological advances, including advances in energy efficiency~~ and ~~distributed~~our ~~generation~~ability ~~sources,~~to ~~which~~recover ~~generate~~these ~~electricity at the site of consumption~~costs;

Ÿ• ~~increasing~~the ~~capital~~cost ~~expenditure~~and availability of fuel such as coal, natural gas, and ~~operating~~enriched ~~expense~~uranium ~~requirements~~used to produce electricity; the cost and ~~our~~availability of purchased power and natural gas for distribution; and the level and volatility of future market prices for such commodities, including the ability to recover ~~these~~the costs ~~through~~for ~~our~~such ~~regulatory frameworks~~commodities;

Ÿ• the ~~cost~~effectiveness ~~and availability~~ of ~~fuel~~our ~~such~~risk asmanagement ~~coal,~~strategies ~~natural gas,~~ and ~~enriched uranium used to produce electricity;~~ the ~~cost~~use ~~and availability~~ of ~~purchased~~financial ~~power~~ and ~~natural~~derivative ~~gas for distribution~~instruments; ~~and the level and volatility of future market prices for such commodities, including the ability to recover the costs for such commodities;~~

Ÿ• the ~~effectiveness~~level and volatility of ~~our~~future ~~risk~~prices ~~management~~for ~~strategies~~power ~~and~~in the ~~use~~Midwest, ofwhich may have a significant effect on the financial ~~and~~condition ~~derivative~~of ~~instruments~~Ameren's Merchant Generation segment;

Ÿ• the ~~level~~development ~~and~~of ~~volatility~~a ofmultiyear ~~future~~capacity ~~prices~~market ~~for~~within ~~power~~MISO inand the ~~Midwest;~~outcomes of MISO's inaugural annual capacity

Ÿauction ~~the~~in ~~development of a capacity market within MISO~~2013;

Ÿ• business and economic conditions, including their impact on interest rates, bad debt expense, and demand for our products;

Ÿ• disruptions of the capital markets, deterioration in credit metrics of the Ameren Companies, or other events that make the Ameren Companies’' access to necessary capital, including short-term credit and liquidity, impossible, more difficult, or more costly;

Ÿ• our assessment of our liquidity, including liquidity concerns for Ameren's Merchant Generation business, and specifically for Genco, which has limited access to third-party financing sources;

Ÿ• the impact of the adoption of new accounting guidance and the application of appropriate technical accounting rules and guidance;

Ÿ• actions of credit rating agencies and the effects of such actions;

Ÿ• the impact of weather conditions and other natural phenomena on us and our customers, including the impacts of droughts, which may cause lower river levels and could limit our energy centers' ability to generate power;

Ÿ• the impact of system outages;

Ÿ• generation, transmission, and distribution asset construction, installation, performance, and cost recovery;

Ÿ• the effects of our increasing investment in electric transmission projects and uncertainty as to whether we will achieve our expected returns in a timely fashion, if at all;

Ÿ• the extent to which Ameren Missouri prevails in its claims against insurers in connection with its Taum Sauk pumped-storage hydroelectric energy center incident;

4• the extent to which Ameren Missouri is permitted by its regulators to recover in rates the investments it made in connection with additional nuclear generation at its Callaway energy center;

~~Table~~• operation of ~~Contents~~Ameren Missouri's Callaway energy center, including planned and unplanned outages, and decommissioning costs;

Ÿ• the ~~extent~~effects toof ~~which~~strategic ~~Ameren~~initiatives, ~~Missouri~~including ismergers, ~~permitted~~acquisitions byand ~~its~~divestitures, ~~regulators~~and toany ~~recover~~related intax ~~rates the investments it made in connection with a proposed second unit at its Callaway energy center~~implications;

Ÿ• ~~impairments~~the impact of ~~long-lived~~current ~~assets~~environmental regulations on utilities and power generating companies and new, ~~intangible~~more stringent or changing requirements, including those related to greenhouse gases, other emissions, cooling water intake structures, CCR, and energy efficiency, that are enacted over time and that could limit or terminate the operation of certain of our energy centers, increase our costs, result in an impairment of our assets, reduce our customers' demand for electricity or ~~goodwill~~natural gas, or otherwise have a negative financial effect;

Ÿ• ~~operation~~the impact of ~~Ameren~~complying ~~Missouri’s~~with ~~Callaway~~renewable energy ~~center,~~portfolio ~~including~~requirements ~~planned and unplanned outages, decommissioning, costs and potential increased costs as a result of nuclear-related developments~~ in ~~Japan in 2011~~Missouri;

Ÿ• ~~the~~labor ~~effects~~disputes, ofworkforce ~~strategic~~reductions, ~~initiatives~~future wage and employee benefits costs, including ~~mergers,~~changes ~~acquisitions~~in discount rates and ~~divestitures~~returns on benefit plan assets;

Ÿ• the ~~impact~~inability of ~~current~~our ~~environmental~~counterparties ~~regulations on utilities~~ and ~~power~~affiliates ~~generating~~to ~~companies~~meet ~~and~~their ~~new,~~obligations ~~more~~with ~~stringent~~respect ~~or changing requirements, including those related~~ to ~~greenhouse gases~~contracts, ~~other~~credit ~~emissions~~agreements, ~~cooling water intake structures, CCR,~~ and ~~energy~~financial ~~efficiency, that are enacted over time and that could limit or terminate~~instruments;

the operation of certain of our generating units, increase our costs, result in an impairment of our assets, reduce our customers’ demand for electricity or natural gas, or otherwise have a negative financial effect;4

ŸTable ~~the impact~~ of ~~complying with renewable energy portfolio requirements in Missouri;~~Contents

Ÿ• ~~labor~~the ~~disputes,~~cost ~~workforce~~and ~~reductions,~~availability ~~future~~of ~~wage~~transmission capacity for the energy generated by Ameren's and ~~employee~~Ameren ~~benefits~~Missouri's ~~costs,~~energy ~~including~~centers ~~changes~~or inrequired ~~discount~~to ~~rates~~satisfy ~~and~~energy ~~returns~~sales onmade ~~benefit~~by ~~plan~~Ameren ~~assets~~or Ameren Missouri;

Ÿ• ~~the~~legal ~~inability of our counterparties~~ and ~~affiliates~~administrative toproceedings; ~~meet their obligations with respect to contracts, credit facilities,~~ and ~~financial instruments;~~

Ÿ• ~~the~~acts ~~cost and availability~~ of ~~transmission~~sabotage, ~~capacity~~war, ~~for~~terrorism, ~~the~~cybersecurity ~~energy~~attacks ~~generated by the Ameren Companies’ energy centers~~ or ~~required~~intentionally todisruptive ~~satisfy energy sales made by the Ameren Companies;~~acts.

ŸGiven ~~legal~~these ~~and~~uncertainties, ~~administrative~~undue ~~proceedings;~~reliance ~~and~~should not be placed on these forward-looking statements. Except to the extent required by the federal securities laws, we undertake no obligation to update or revise publicly any forward-looking statements to reflect new information or future events.

ŸPART ~~acts of sabotage, war, terrorism, cybersecurity attacks or intentionally disruptive acts.~~I

~~Given~~ITEM ~~these uncertainties, undue reliance should not be placed on these forward-looking statements~~1. ~~Except to the extent required by the federal securities laws, we undertake no obligation to update or revise publicly any forward-looking statements to reflect new information or future events.~~ BUSINESS

~~PART I~~ GENERAL

~~ITEM~~Ameren, 1headquartered in St. ~~BUSINESS~~Louis, Missouri, is a public utility holding company under PUHCA 2005, administered by FERC. Ameren was formed in 1997 by the merger of Ameren Missouri and CIPSCO Inc. Ameren acquired CILCORP in 2003 and IP in 2004. Ameren’s primary assets are its equity interests in its subsidiaries, including Ameren Missouri, Ameren Illinois and AER. Ameren’s subsidiaries are separate, independent legal entities with separate businesses, assets, and liabilities. These subsidiaries operate, as the case may be, rate-regulated electric generation, transmission, and distribution businesses, rate-regulated natural gas transmission and distribution businesses, and merchant generation businesses in Missouri and Illinois. Dividends on Ameren’s common stock and the payment of other expenses by Ameren depend on distributions made to it by its subsidiaries. In December 2012, Ameren determined that it intends to, and it is probable that it will, exit its Merchant Generation business before the end of the previously estimated useful lives of that business's long-lived assets. This determination resulted from Ameren’s analysis of the current and projected future financial condition of its Merchant Generation business segment, including the need to fund Genco debt maturities beginning in 2018 and its conclusion that this business segment is no longer a core component of its future business strategy. In consideration of this determination, Ameren has begun planning to reduce, and ultimately eliminate, the Merchant Generation segment's reliance on Ameren's financial support and shared services support. Ameren intends to allocate its capital resources to those business opportunities, including electric and natural gas transmission, which offer the most attractive risk-adjusted return potential.

~~GENERAL~~ Below is a summary description of Ameren Missouri, Ameren Illinois and AER. A more detailed description can be found in Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report.

• Ameren, ~~headquartered in St. Louis,~~ Missouri, isoperates a public utility holding company under PUHCA 2005 administered by FERC. Ameren was formed in 1997 by the merger of Ameren Missouri and CIPSCO Inc. Ameren acquired CILCORP in 2003 and IP in 2004. Ameren’s primary assets are the common stock of its subsidiaries, including Ameren Missouri, Ameren Illinois and AER. Ameren’s subsidiaries are separate, independent legal entities with separate businesses, assets, and liabilities. These subsidiaries operate, as the case may be, rate-regulated electric generation, transmission, and distribution ~~businesses~~business, and a rate-regulated natural gas transmission and distribution ~~businesses,~~business ~~and merchant generation businesses~~ in Missouri ~~and Illinois~~. Dividends on Ameren’s common stock and the payment of other expenses by Ameren depend on distributions made to it by its subsidiaries. Below is a summary description of Ameren Missouri, Ameren Illinois and AER. A more detailed description can be found in Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report.

Ÿ• Ameren ~~Missouri~~Illinois operates a rate-regulated electric ~~generation, transmission~~ and ~~distribution business, and a rate-regulated~~ natural gas transmission and distribution business in ~~Missouri~~Illinois.

Ÿ• ~~Ameren~~AER ~~Illinois~~consists ~~operates~~of a non-rate-regulated ~~electric~~operations, ~~and~~including ~~natural~~Genco, ~~gas~~AERG, ~~transmission~~Marketing Company, and, ~~distribution~~through ~~business~~Genco, an 80% ownership interest in ~~Illinois~~EEI, which Ameren consolidates for financial reporting purposes.

The following table presents our total employees at December 31, 2012:

Ÿ AER consists of non-rate-regulated operations, including Genco, AERG, Marketing Company and Medina Valley (through February 2012). Genco operates a merchant electric generation business in Illinois and holds an 80% ownership interest in EEI.



Ameren^(a)	9,097
Ameren Missouri	3,997
Ameren Illinois	2,994
AER	713
Ameren Services	1,393

~~The~~(a) ~~following~~Total ~~table~~for ~~presents our~~Ameren ~~total~~includes ~~employees~~Ameren atregistrant ~~December 31,~~and ~~2011:~~nonregistrant subsidiaries.

Ameren(a)			9,323
Ameren Missouri			4,333
Ameren Illinois			2,793
Genco			618

As of January 1, 2013, the IBEW, the IUOE, the LIUNA, and the UA labor unions collectively represented about 57% of Ameren’s total employees. They represented 64% of the employees at Ameren Missouri and 63% at Ameren Illinois. The collective bargaining agreements have three- to five-year terms, and expire between 2013 and 2016. Several collective bargaining agreements between Ameren subsidiaries and the IBEW, IUOE, the LIUNA and the UA labor unions, covering approximately 2,900 employees expire during 2013.

~~(a)~~For ~~Total~~additional ~~for~~information ~~Ameren~~about ~~includes~~the ~~Ameren~~development ~~registrant~~of our businesses, our business operations, and ~~nonregistrant~~factors ~~subsidiaries~~affecting our operations and financial position, see Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, of this report and Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report.

AsBUSINESS of January 1, 2012, the IBEW, the IUOE, the LIUNA, and the UA labor unions collectively represented about 58% of Ameren’s total employees. They represented 63% of the employees at Ameren Missouri, 65% at Ameren Illinois, and 67% at Genco. The collective bargaining agreements have three- to five-year terms, and expire between 2012 and 2016. Several collective bargaining agreements between Ameren subsidiaries and the IBEW, covering approximately 3,500 employees, expire during 2012. Additionally, employees providing security at the Callaway energy center elected to organize under the UGSOA in August 2011. SEGMENTS

5Ameren has three reporting segments: Ameren Missouri, Ameren Illinois, and Merchant Generation. See Note 18 – Segment Information under Part II, Item 8, of this report for additional information on reporting segments.

~~Table~~RATES ofAND ~~Contents~~REGULATION

~~Negotiations for a collective bargaining agreement with these employees began in December 2011 and are ongoing.~~ Rates

~~For~~The ~~additional~~rates ~~information~~that ~~about~~Ameren ~~the~~Missouri ~~development of our businesses, our business operations,~~ and ~~factors~~Ameren ~~affecting~~Illinois ~~our~~are ~~operations and financial position, see Management’s Discussion and Analysis of Financial~~

~~Condition and Results of Operations under Part II, Item 7, of this report and Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report.~~ 5

~~BUSINESS~~Table ~~SEGMENTS~~of Contents

allowed to charge for their utility services significantly influence the results of operations, financial position, and liquidity of these companies and Ameren. ~~has~~The ~~three~~electric ~~reportable~~and ~~segments:~~natural gas utility industry is highly regulated. The utility rates charged to Ameren Missouri, and Ameren Illinois customers are determined, in large part, by governmental entities, including the MoPSC, the ICC, and ~~Merchant~~FERC. ~~Generation~~Decisions by these entities are influenced by many factors, including the cost of providing service, the prudency of expenditures, the quality of service, regulatory staff knowledge and experience, economic conditions, public policy, and social and political views. ~~See~~Decisions ~~Note~~made 18by –these ~~Segment~~governmental ~~Information~~entities ~~under~~regarding ~~Part II~~rates are largely outside of Ameren Missouri’s and Ameren Illinois’ control. These decisions, ~~Item 8~~as well as the regulatory lag involved in filing and getting new rates approved, could have a material impact on the results of ~~this~~operations, ~~report~~financial ~~for~~position, and liquidity of Ameren, Ameren Missouri and Ameren Illinois. Rate orders are also subject to appeal, which creates additional ~~information~~uncertainty as to the rates Ameren Missouri and Ameren Illinois are ultimately allowed to charge for their services. The effect of regulatory lag on ~~reporting~~Ameren ~~segments~~Illinois’ electric distribution business is mitigated to some extent through the use of the formula ratemaking regulatory framework established under the IEIMA. Beginning in 2013, regulatory lag on Ameren Illinois' and ATXI's electric transmission business will be mitigated to some extent through the use of the FERC revenue requirement reconciliation. To mitigate regulatory lag on Ameren Illinois' natural gas distribution business, recent rate requests have been filed with the ICC using a future test year.

~~RATES~~The ~~AND~~ICC ~~REGULATION~~regulates rates and other matters for Ameren Illinois and ATXI. The MoPSC regulates rates and other matters for Ameren Missouri. The FERC regulates Ameren Missouri, Ameren Illinois, ATXI, Genco, EEI, and AERG as to their ability to charge market-based rates for the sale and transmission of energy in interstate commerce and various other matters discussed below under General Regulatory Matters.

~~Rates~~About 53% of Ameren’s electric and 15% of its natural gas operating revenues were subject to regulation by the MoPSC in the year ended December 31, 2012. About 29% of Ameren’s electric and 85% of its natural gas operating revenues were subject to regulation by the ICC in the year ended December 31, 2012. Wholesale revenues for Ameren Missouri, Ameren Illinois, Genco, Marketing Company and AERG are subject to FERC regulation, but not subject to direct MoPSC or ICC regulation.

~~The rates that~~ Ameren Missouri and Ameren Illinois are allowed to charge for their utility services significantly influence the results of operations, financial position, and liquidity of these companies and Ameren. The electric and natural gas utility industry is highly regulated. The utility rates charged to Ameren Missouri and Ameren Illinois customers are determined, in large part, by governmental entities, including the MoPSC, the ICC, and FERC. Decisions by these entities are influenced by many factors, including the cost of providing service, the prudency of expenditures, the quality of service, regulatory staff knowledge and experience, economic conditions, public policy, and social and political views. Decisions made by these governmental entities regarding rates are largely outside of Ameren Missouri’s and Ameren Illinois’ control. These decisions, as well as the regulatory lag involved in filing and getting new rates approved, could have a material impact on the results of operations, financial position, and liquidity of Ameren, Ameren Missouri and Ameren Illinois. Rate orders are also subject to appeal, which creates additional uncertainty as to the rates Ameren Missouri and Ameren Illinois are ultimately allowed to charge for their services. Beginning in 2012, the effect of regulatory lag on Ameren Illinois’ electric distribution business is expected to be mitigated through the use of the formula ratemaking regulatory framework established under the IEIMA.

The ICC regulates rates and other matters for Ameren Illinois and ATXI. The MoPSC regulates rates and other matters for Ameren Missouri. The FERC regulates Ameren Missouri, Ameren Illinois, Genco and ATXI as to their ability to charge market-based rates for the sale and transmission of energy in interstate commerce and various other matters discussed below under General Regulatory Matters. Electric

~~About~~Almost 49100% of Ameren Missouri’s electric ~~and 16% of its natural gas~~ operating revenues were subject to regulation by the MoPSC in the year ended December 31, ~~2011~~2012. ~~About 30% of Ameren’s electric and 84% of its natural gas operating~~

~~revenues~~In ~~were~~December ~~subject~~2012, tothe ~~regulation~~MoPSC byissued ~~the~~an ~~ICC~~order inapproving ~~the~~an ~~year~~increase ~~ended~~for ~~December 31,~~Ameren ~~2011.~~Missouri ~~Wholesale~~in annual revenues for ~~Ameren~~electric ~~Missouri,~~service ~~Ameren~~of ~~Illinois~~$260 million, ~~Genco~~including ~~and~~$84 ~~AERG~~million ~~are~~related ~~subject~~ to ~~FERC~~an ~~regulation, but~~anticipated ~~not~~increase ~~subject~~in tonormalized ~~direct~~net fuel costs above the net fuel costs included in base rates previously authorized by the MoPSC orin ~~ICC~~its ~~regulation~~July 2011 electric rate order. The annual increase

~~Ameren~~also ~~Missouri~~included $80 million for recovery of the costs associated with energy efficiency programs under the MEEIA. The remaining annual increase of $96 million approved by the MoPSC was for energy infrastructure investments and other non-fuel costs, including $10 million for increased pension and other post-employment benefit costs and $6 million for increased amortization of regulatory assets. The revenue increase was based on a 9.8% return on equity, a capital structure composed of 52.3% common equity, and a rate base of $6.8 billion. The new rates became effective on January 2, 2013.

~~Electric~~If certain criteria are met, Ameren Missouri’s electric rates may be adjusted without a traditional rate proceeding. The FAC permits 95% of prudently incurred fuel, emission allowances, purchased power costs, transmission costs and MISO costs and revenues to be passed directly to customers. The MoPSC's December 2012 electric rate order changed the FAC to include activated carbon, limestone and urea costs, along with transmission revenues, starting in 2013.

~~About~~FERC ~~99%~~regulates the rates charged and the terms and conditions for electric transmission services. Each RTO separately files a regional transmission tariff for approval by FERC. All transmission service within that RTO is then subjected to that tariff. As a member of MISO, Ameren Missouri’s ~~electric~~transmission ~~operating~~rate ~~revenues~~is ~~were~~calculated ~~subject~~in toaccordance ~~regulation by~~with the ~~MoPSC~~MISO OATT. The transmission rate is updated in ~~the~~June of each year; ~~ended~~it ~~December 31,~~is ~~2011~~based on Ameren Missouri’s filings with ~~the~~FERC. ~~remainder~~This ~~subject~~rate is not directly charged to ~~FERC~~Missouri ~~regulation~~retail customers, because in Missouri the MoPSC includes transmission-related costs and revenues in setting bundled retail rates.

InNatural July 2011, the MoPSC issued an order approving an increase for Ameren Missouri in annual revenues for electric service of $173 million, including $52 million related to an increase in normalized net fuel costs above the net fuel costs included in base rates previously authorized by the MoPSC in its May 2010 electric rate order. The revenue increase was based on a 10.2% return on equity, a capital structure composed of 52.2% common equity, and a rate base of $6.6 billion. The rate changes became effective on July 31, 2011. The MoPSC order approved the continued use of Ameren Missouri’s vegetation management and infrastructure cost tracker, pension and postretirement benefit cost tracker, and FAC at the current 95% sharing level. The MoPSC order shortened the FAC recovery and refund period from 12 months to eight months. Additionally, the MoPSC order provided for a tracking mechanism for uncertain income tax positions. Gas

InAll ~~February~~of ~~2012,~~ Ameren Missouri’s ~~filed~~natural agas ~~request~~operating ~~with~~revenues ~~the~~were ~~MoPSC~~subject to ~~increase~~regulation ~~its annual revenues for electric service~~ by ~~$376 million. Included in this requested increase was a $103 million increase in normalized net fuel costs above~~ the ~~net~~MoPSC ~~fuel costs included~~ in ~~base rates previously authorized by~~ the ~~MoPSC~~year inended ~~its~~December 31, ~~July 2011 electric rate order~~2012. ~~Absent~~In ~~initiation~~January ~~of this general rate proceeding~~2011, ~~95% of this amount would have been reflected in rate adjustments implemented under Ameren Missouri’s FAC. The request also included recovery of~~ the ~~costs~~MoPSC ~~associated~~approved ~~with energy efficiency programs under the MEEIA, including energy efficiency investments,~~ a ~~storm~~stipulation ~~cost tracking mechanism, plant-in-service accounting treatment,~~ and ~~recovery~~agreement ofthat ~~other~~allowed ~~costs~~Ameren ~~incurred~~Missouri to ~~provide systemwide reliability improvements for customers, among other items. The electric rate~~ increase ~~request~~annual ~~was~~natural ~~based~~gas onrevenues aby ~~10.75% return on equity, a capital structure composed of 52% common equity, an aggregate electric rate base of~~ $~~6.8 billion,~~9 ~~and a test year ended September 30, 2011, with certain pro forma adjustments expected through the anticipated true-up date of July 31, 2012~~million. ~~A decision by the MoPSC in this proceeding is expected in December 2012.~~

~~FERC~~If ~~regulates~~certain ~~the~~criteria are met, Ameren Missouri’s natural gas rates ~~charged~~may ~~and~~be ~~the~~adjusted ~~terms~~without ~~and~~a ~~conditions for~~traditional ~~electric~~rate ~~transmission~~proceeding. ~~services~~PGA clauses permit prudently incurred natural gas costs to be passed directly to customers. ~~Each~~The ~~RTO~~ISRS ~~separately~~also ~~files~~permits aprudently ~~regional~~incurred ~~transmission~~natural ~~tariff~~gas ~~for~~infrastructure ~~approval~~replacement bycosts ~~FERC~~to be passed directly to customers. ~~All~~The ~~transmission~~return ~~service~~on ~~within~~equity ~~that~~to ~~RTO~~be used by Ameren Missouri for purposes of the ISRS tariff filing is ~~then~~ 10%.

6For additional information on Missouri rate matters, including Ameren Missouri’s 2012 electric rate order and the related court appeals, see Results of Operations and Outlook in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, Quantitative and Qualitative Disclosures About Market Risk under Part II, Item 7A, and Note 2 – Rate and Regulatory Matters, and Note 15 – Commitments and Contingencies under Part II, Item 8, of this report.

~~Table of Contents~~6

~~subjected~~Table ~~to that tariff. As a member~~ of ~~MISO, Ameren Missouri’s transmission rate is calculated in accordance with the MISO OATT. The transmission rate is updated in~~ Contents

~~June of each year; it is based on~~ Ameren ~~Missouri’s filings with FERC. This rate is not directly charged to Missouri retail customers, because in Missouri the MoPSC includes transmission-related costs in setting bundled retail rates.~~ Illinois

~~Natural Gas~~ Electric

~~All~~About 99% of Ameren ~~Missouri~~Illinois’s ~~natural~~electric ~~gas~~ operating revenues were subject to regulation by the ~~MoPSC~~ICC in the year ended December 31, ~~2011. In January 2011~~2012, ~~the~~with ~~MoPSC approved a stipulation and agreement that allowed Ameren Missouri to increase annual natural gas revenues by $9 million. The new rates became effective on February 20, 2011. As part of~~ the ~~stipulation~~remainder ~~and~~subject ~~agreement, Ameren Missouri agreed not~~ to ~~file~~FERC ~~a separate natural gas rate increase request before December 31, 2012; however, Ameren Missouri can file a combined natural gas and electric rate case before that date~~regulation. Further, this agreement does not prevent Ameren Missouri from filing to recover infrastructure replacement costs through an ISRS during this moratorium. The return on equity to be used by Ameren Missouri for purposes of the ISRS tariff filing is 10%.

IfUnder ~~certain~~the ~~criteria~~Illinois ~~are~~Customer ~~met~~Choice Law, ~~Ameren~~all ~~Missouri’s~~electric ~~natural~~customers ~~gas~~in ~~rates~~Illinois may bechoose ~~adjusted~~their ~~without~~own aelectric ~~traditional~~energy ~~rate~~provider. ~~proceeding~~However, Ameren Illinois is required to serve as the provider of last resort (POLR) for electric customers within its territory who have not chosen an alternative retail electric supplier. ~~PGA~~Ameren ~~clauses~~Illinois’ ~~permit prudently~~obligation ~~incurred~~to ~~natural~~provide ~~gas~~POLR ~~costs~~electric service varies by customer size. Ameren Illinois is not required to beoffer ~~passed~~fixed-priced ~~directly~~electric service to customers with electric demands of 400 kilowatts or greater, as the ~~consumer.~~market ~~The~~for ~~ISRS~~service ~~also~~to ~~permits~~this ~~prudently~~group ~~incurred~~of ~~natural~~customers ~~gas~~has ~~infrastructure~~been ~~replacement~~declared competitive. Power and related procurement costs toincurred beby Ameren Illinois are passed directly to ~~the~~its ~~consumer.~~customers through a cost recovery mechanism.

~~For~~In ~~additional~~2012, ~~information~~Ameren onIllinois ~~Missouri~~elected ~~rate~~to ~~matters,~~participate ~~including~~in ~~Ameren~~the ~~Missouri’s~~performance-based ~~pending~~formula ratemaking process established pursuant to the IEIMA by filing initial performance-based formula rates with the ICC. The IEIMA was designed to provide for the recovery of actual costs of electric ~~rate~~delivery ~~case,~~service that are prudently incurred and ~~Ameren~~to ~~Missouri’~~reflect the utility's ~~2009, 2010~~actual ~~and~~regulated ~~2011~~capital ~~electric~~structure through the inclusion of a formula for calculating the return on equity component of the cost of capital. The return on equity component of the formula rate ~~orders~~is ~~and~~equal ~~related~~to ~~court~~the ~~appeals~~average ~~and~~for ~~regulatory~~the ~~proceedings,~~calendar ~~see~~year ~~Results~~of the monthly yields of ~~Operations~~30-year ~~and~~United ~~Outlook~~States intreasury ~~Management’s~~bonds ~~Discussion~~plus 590 basis points for 2012 and ~~Analysis~~580 basis points thereafter. Ameren Illinois' actual return on equity relating to electric delivery service will be subject to a collar adjustment on earnings in excess of ~~Financial~~50 ~~Condition~~basis ~~and~~points ~~Results~~above or below its allowed return. The IEIMA provides for an annual reconciliation of ~~Operations~~the ~~under~~revenue ~~Part~~requirement ~~II,~~necessary ~~Item 7, Quantitative~~to ~~and~~reflect ~~Qualitative~~the ~~Disclosures~~actual ~~About~~costs ~~Market~~incurred ~~Risk~~in ~~under~~a ~~Part~~given ~~II,~~year ~~Item 7A,~~with ~~and~~the ~~Note~~revenue 2requirement –that ~~Rate~~was ~~and~~in ~~Regulatory~~effect ~~Matters~~for that year, ~~and~~including ~~Note~~an 15allowed –return ~~Commitments~~on ~~and~~equity. ~~Contingencies~~This ~~under~~annual ~~Part~~revenue IIreconciliation, ~~Item 8~~along with the collar adjustment, ofif ~~this~~necessary, ~~report.~~will be collected from or refunded to customers in a subsequent year.

Ameren Illinois is also subject to performance standards under the IEIMA. Failure to achieve the standards will result in a reduction in the company's allowed return on equity calculated under the formula. The performance standards include improvements in service reliability to reduce both the frequency and duration of outages, reduction in the number of estimated bills, reduction of consumption on inactive meters, and a reduction in uncollectible accounts expense. The IEIMA provides for return on equity penalties totaling up to 30 basis points in 2013 through 2015, 34 basis points in 2016 through 2018, and 38 basis points in 2019 through 2022 if the performance standards are not met. The formula ratemaking process is effective until the end of 2017, but could be extended by the Illinois General Assembly for an additional five years. The formula ratemaking

~~Electric~~process would also terminate if the average residential rate increases by more than 2.5% annually from June 2011 through May 2014. The average residential rate includes generation service, which is outside of Ameren Illinois’ control, as Ameren Illinois is required to purchase all of its power through procurement processes administered by the IPA.

~~About~~Between ~~99%~~2012 ofand 2021, Ameren Illinois’ is required, pursuant to the IEIMA, to invest $625 million in capital expenditures incremental to Ameren Illinois' average electric ~~operating~~delivery ~~revenues~~capital ~~were~~expenditures for calendar years 2008 through 2010 to modernize its distribution system. Such investments are expected to encourage economic development and to create an estimated 450 additional jobs within Illinois. Ameren Illinois is subject to ~~regulation~~monetary bypenalties ~~the~~if ~~ICC~~450 inadditional jobs are not created during the ~~year~~peak ~~ended~~program ~~December 31~~year. Also, ~~2011~~Ameren ~~with~~ Illinois is required to contribute $1 million annually for certain nonrecoverable customer assistance programs and $1 million annually to the ~~remainder~~Illinois ~~subject~~Science and Energy Innovation Trust for as long as Ameren Illinois participates in the formula ratemaking process. Ameren Illinois also was required to ~~FERC~~make ~~regulation~~a one-time $7.5 million nonrecoverable donation to the Illinois Science and Energy Innovation Trust in 2012.

~~Under~~Ameren Illinois' initial filing under IEIMA was based on 2010 recoverable costs and expected net plant additions for 2011 and 2012. In September 2012, the ICC issued an order approving an Ameren Illinois ~~Customer~~electric ~~Choice~~delivery ~~Law~~service revenue requirement of $779 million, ~~all~~which was a $55 million decrease from the electric ~~customers~~delivery inservice ~~Illinois~~revenue ~~may~~requirement ~~choose~~allowed ~~their own~~in the pre-IEIMA 2010 electric ~~energy~~delivery ~~provider~~service rate order. ~~However~~The rates became effective on October 19, 2012, and were effective through the end of 2012. In October 2012, Ameren Illinois isfiled ~~required~~an appeal of the ICC order to ~~serve~~the Appellate Court of the Fourth District of Illinois. A decision by the appellate court is expected in 2013. Ameren Illinois believes that the ICC has incorrectly implemented the IEIMA by using an average rate base as opposed to a year-end rate base in setting rates, through its treatment of accumulated deferred income taxes, and through the ~~provider~~method it used for calculating the equity portion of ~~last~~Ameren ~~resort~~Illinois' ~~(POLR)~~capital structure and the method for ~~electric~~calculating ~~customers~~interest ~~within~~on the revenue requirement reconciliation and return on equity collar. The ICC's September 2012 order jeopardizes Ameren Illinois' ongoing ability to implement infrastructure improvements to the extent and on the timetable envisioned in the IEIMA. Until the uncertainty surrounding how the Illinois law will ultimately be implemented is removed, Ameren Illinois is reducing its ~~territory~~IEIMA ~~who~~capital ~~have~~spending ~~not~~with ~~chosen~~a ancorresponding ~~alternative~~negative ~~retail~~ effect on the job creation that the legislature sought to effectuate with the law. Although Ameren Illinois intends to meet its IEIMA capital spending requirements, it is proceeding on a slower investment schedule than previously contemplated.

~~electric~~In ~~supplier.~~April 2012, Ameren Illinois’ ~~obligation~~submitted to ~~provide~~the ~~POLR~~ICC ~~electric~~an ~~service~~update ~~varies~~filing byunder ~~customer~~IEIMA ~~size.~~based ~~Ameren~~on ~~Illinois~~2011 isrecoverable ~~not~~costs ~~required~~and toexpected ~~offer~~net ~~fixed-priced~~plant ~~electric~~additions ~~service~~for to2012. ~~customers with~~In ~~electric~~December ~~demands of 400 kilowatts or greater~~2012, as the ~~market~~ICC ~~for~~issued ~~service~~an toorder ~~this~~approving ~~group~~an ofAmeren ~~customers~~Illinois ~~has~~electric ~~been~~delivery ~~declared~~service ~~competitive.~~revenue ~~Power~~requirement ~~and~~of ~~related~~$764 ~~procurement~~million, ~~costs~~which ~~incurred~~was bya ~~Ameren~~$15 ~~Illinois~~million ~~are~~decrease ~~passed~~in ~~directly~~the torevenue ~~its~~requirement ~~customers~~allowed ~~through~~in ~~a cost~~the ~~recovery~~ICC ~~mechanism.~~

In October 2011, the IEIMA was enacted into law and became effective immediately. Certain amendments to the IEIMA became effective on December 30, 2011. On January 3, 2012, Ameren Illinois elected to participate in the performance-based formula ratemaking process established pursuant to the IEIMA by filing initial performance-based formula rates with the ICC. The initial filing, based on 2010 recoverable costs and expected net plant additions for 2011 and 2012, will result in new electric delivery service rates in October 2012. Pending ICC approval, the initial filing will result in a decrease in Ameren Illinois revenues for electric delivery service of $19 million, on an annualized basis. Ameren Illinois anticipates making an update filing by May 1, 2012, based on 2011 costs and expected net plant additions for 2012, that would result in new electric delivery service rates on January 1, 2013. 7

ByTable ~~choosing to opt-in, Ameren Illinois will participate in a performance-based formula process for determining rates that will provide for the recovery~~ of actual costs of electric delivery service that are prudently incurred, reflect the utility’s actual regulated capital structure and include a formula for calculating the return on equity component of the cost of capital. The equity component of the formula rate will be equal to the average for the applicable calendar year of the monthly average yields of 30-year United States treasury bonds plus 590 basis points for 2012 and 580 basis points thereafter. Ameren Illinois’ actual return on equity relating to electric delivery service will be subject to a collar adjustment on earnings in excess of 50 basis points above or below its allowed return. Beginning in 2012, the law provides for an annual reconciliation of revenues to costs prudently and reasonably incurred. This annual revenue reconciliation along with the collar adjustment, if necessary, will be collected from or refunded to customers in a subsequent year. Contents

~~Ameren~~initial ~~Illinois~~filing ~~will~~order. ~~also~~The berates ~~subject~~became toeffective ~~five~~on ~~performance~~January ~~standards~~1, ~~under~~2013, ~~the~~and ~~IEIMA~~will ~~whereby the~~be ~~failure~~effective tothrough ~~achieve~~ the ~~standards~~end ~~will~~of ~~result in a reduction in its allowed return on equity calculated under the formula~~2013. ~~The~~Ameren ~~performance~~Illinois ~~standards~~will ~~include~~submit ~~improvements in service reliability~~ to ~~reduce~~the ~~both~~ICC during the ~~frequency~~second ~~and~~quarter ~~duration~~ of ~~outages, improvements~~2013 inan ~~customer~~update ~~satisfaction~~filing ~~scores,~~based ~~reduction~~on in2012 ~~the~~recoverable ~~number~~costs ~~of estimated bills,~~ and aexpected ~~reduction~~net inplant ~~uncollectible~~additions ~~accounts expense. The IEIMA provides~~ for ~~return on equity penalties totaling up to 30 basis points in~~ 2013 ~~through 2015~~, ~~34 basis~~which ~~points~~will indetermine ~~2016~~rates ~~through~~that ~~2018 and 38 basis points in 2019 through 2022 if the performance standards~~ are ~~not met. The formula ratemaking process is~~ effective ~~until~~during ~~the end of 2017, but could be extended by the Illinois General Assembly~~ 2014.

7In December 2012, the ICC approved Ameren Illinois' advanced metering infrastructure deployment plan, which outlines how Ameren Illinois will comply with the IEIMA requirement to spend $360 million on smart grid assets over ten years on a cost-beneficial basis to its electric customers. The plan targets the second quarter of 2014 to begin installation of smart meters.

~~Table~~Also, ofAmeren ~~Contents~~Illinois has approval from the ICC to use cost recovery mechanisms for energy efficiency programs, environmental costs and bad debt expense not recovered in base rates.

Ameren Illinois has a tariff rider to recover the costs of asbestos-related litigation claims, subject to the following terms: 90% of cash expenditures in excess of the amount included in base electric rates are to be recovered from a trust fund that was established when Ameren acquired IP. At December 31, 2012, the trust fund balance was $23 million, including accumulated interest. If cash expenditures are less than the amount in base rates, Ameren Illinois will contribute 90% of the difference to the fund. Once the trust fund is depleted, 90% of allowed cash expenditures in excess of base rates will be recovered through charges assessed to customers under the tariff rider. Following the Ameren Illinois Merger, this rider is applicable only for anclaims ~~additional~~that ~~five~~occurred ~~years~~within IP’s historical service territory. ~~The~~Similarly, ~~formula~~the ~~ratemaking~~rider ~~process~~will permit recovery only from customers within IP’s historical service territory.

~~would~~As ~~also~~a ~~terminate~~member ifof MISO, Ameren Illinois' transmission rates are calculated in accordance with the ~~average residential~~MISO OATT. Ameren Illinois has received FERC approval to use company-specific, forward-looking rate ~~increases~~formula bytemplates ~~more~~in ~~than~~setting 2its transmission rates.5% ~~annually~~These ~~from~~forward-looking ~~June~~rates ~~2011~~are ~~through~~updated ~~May~~in ~~2014~~January each year based on forecasted information, with an annual reconciliation to the actual revenue requirement based on the costs incurred. In Illinois, the AMIL pricing zone rate is charged directly to wholesale customers and alternative retail electric suppliers, which serve unbundled retail load. For Ameren Illinois retail customers who have not chosen an alternative retail electric supplier, the AMIL transmission rate, as well as other MISO-related costs, are collected through a rider mechanism in Ameren Illinois' retail distribution tariffs.

~~Between~~Natural ~~2012 and 2021, Ameren Illinois will be required to invest $625 million in capital expenditures~~ Gas

~~incremental~~All toof Ameren Illinois’ ~~average~~natural ~~electric~~gas ~~delivery~~operating ~~capital~~revenues ~~expenditures~~were ~~for~~subject ~~calendar years~~to ~~2008~~regulation ~~through~~by ~~2010~~the toICC ~~modernize~~in ~~its~~the ~~distribution~~year ~~system.~~ended ~~Such~~December 31, ~~investments are~~ 2012.

~~expected~~On toJanuary ~~encourage~~25, ~~economic~~2013, ~~development and create an estimated 450 additional jobs within Illinois.~~ Ameren Illinois isfiled ~~subject~~a torequest ~~monetary~~with ~~penalties if 450 additional jobs are not created during~~ the ~~peak~~ICC ~~program year. Also, Ameren Illinois will be required~~ to ~~contribute~~increase $1its ~~million~~annual ~~annually~~revenues for ~~certain nonrecoverable~~natural ~~customer~~gas ~~assistance~~delivery ~~programs,~~service upby ~~to a total of~~ $1050 million ~~through 2021, for as long as Ameren Illinois participates in the formula ratemaking process~~. The ~~Ameren~~request ~~Illinois~~was ~~will~~based ~~also~~on ~~be required to make~~ a ~~one-time $7~~10.54% ~~million nonrecoverable~~return donation to the Illinois Science and Energy Innovation Trust in 2012, as well as an approximate $1 million annual donation to the same trust for as long as it participates in the formula ratemaking process.

~~Ameren~~on ~~Illinois~~equity, ~~has~~ a ~~tariff~~capital ~~rider~~structure tocomposed ~~recover the costs~~ of ~~asbestos-related~~51.8% ~~litigation~~common ~~claims~~equity, ~~subject~~and toa ~~the~~rate ~~following~~base ~~terms: 90%~~ of ~~cash expenditures~~$1.1 inbillion. ~~excess~~In ofan ~~the~~attempt ~~amount~~to ~~included~~reduce inregulatory ~~base~~lag, ~~electric~~Ameren ~~rates~~Illinois ~~are~~is tousing ~~be recovered from~~ a ~~trust~~future ~~fund~~test ~~that~~year, ~~was~~2014, ~~established~~in ~~when~~this ~~Ameren acquired IP~~proceeding. AtA ~~December 31,~~decision ~~2011,~~by the ~~trust~~ICC ~~fund~~in ~~balance~~this ~~was~~proceeding ~~$23 million,~~is ~~including~~required ~~accumulated interest.~~by IfDecember ~~cash~~2013. Ameren ~~expenditures~~Illinois ~~are~~cannot ~~less~~predict ~~than~~ the ~~amount~~level inof ~~base~~any ~~rates,~~delivery ~~Ameren~~service ~~Illinois~~rate ~~will~~changes ~~contribute 90% of~~ the ~~difference~~ICC tomay ~~the~~approve, ~~fund.~~when ~~Once~~any ~~the~~rate ~~trust~~changes ~~fund~~may isgo ~~depleted~~into effect, ~~90%~~or ofwhether ~~allowed~~any ~~cash~~rate ~~expenditures~~changes inthat ~~excess~~may ofeventually ~~base~~be ~~rates~~approved will be ~~recovered through~~sufficient ~~charges assessed~~ to ~~customers~~enable ~~under the tariff rider. Following the~~ Ameren Illinois ~~Merger,~~to ~~this~~recover ~~rider~~its iscosts ~~applicable~~and ~~only~~earn ~~for~~a ~~claims~~reasonable ~~that~~return ~~occurred~~on ~~within~~its ~~IP’s~~investments ~~historical~~when ~~service territory. Similarly,~~ the ~~rider~~rate ~~will~~changes ~~permit~~go ~~recovery~~into ~~only from customers within IP’s historical service territory~~effect.

AsIf acertain ~~member~~criteria ofare ~~MISO~~met, Ameren Illinois’ ~~transmission~~natural ~~rate~~gas ~~is calculated~~rates inmay ~~accordance~~be ~~with~~adjusted ~~the~~without ~~MISO~~a ~~OATT.~~traditional ~~The~~rate ~~transmission~~proceeding. ~~rate~~PGA isclauses ~~updated~~permit inprudently ~~June~~incurred ofnatural ~~each~~gas ~~year~~costs ~~based~~to onbe ~~Ameren~~passed ~~Illinois’~~directly ~~filings~~to ~~with~~the ~~FERC~~customer. ~~This~~Also, ~~rate~~Ameren isIllinois ~~charged~~has ~~directly~~approval tofrom ~~wholesale~~the ~~customers~~ICC ~~and~~to ~~alternative~~use ~~retail~~cost ~~electric~~recovery ~~suppliers. Retail~~mechanisms ~~customers~~for ~~who~~energy ~~have~~efficiency ~~not~~programs, ~~chosen~~certain anenvironmental ~~alternative~~costs ~~retail~~and ~~electric~~bad ~~supplier~~debt ~~pay~~expense ~~the~~not ~~transmission~~recovered ~~rate~~in ~~through~~base ~~a rider mechanism~~rates.

~~Natural~~For ~~Gas~~ additional information on Illinois rate matters, including the IEIMA and the Ameren Illinois' natural gas case filed in January 2013, see Results of Operations and Outlook in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, Quantitative and Qualitative Disclosures About Market Risk under Part II, Item 7A, and Note 2 – Rate and Regulatory Matters, and Note 15 – Commitments and Contingencies under Part II, Item 8, of this report.

~~All~~Merchant ~~of Ameren Illinois’ natural gas operating revenues were subject to regulation by the ICC in the year ended December 31, 2011.~~ Generation

Merchant Generation revenues are determined by market conditions and contractual arrangements. We expect the Merchant Generation energy centers to have 5,522 megawatts of capacity available for the 2013 peak summer electrical demand. In ~~January~~December 2012, Ameren determined that it intends to, and it is probable that it will, exit its Merchant Generation business before the ~~ICC~~end ~~issued~~of athe ~~rate~~previously ~~order~~estimated useful lives of that ~~approved~~business's anlong-lived ~~increase~~assets. As discussed below, Genco and AERG sell all of their power and capacity to Marketing Company through power supply agreements. Marketing Company attempts to optimize the value of those assets and to mitigate risks through a variety of techniques, including wholesale sales of capacity and energy, retail sales in ~~Ameren~~the non-rate-regulated Illinois market, spot market sales primarily in MISO and PJM, and financial hedging transactions, including options and other derivatives. Marketing Company enters into long-term and short-term contracts. Marketing Company’s ~~annual~~counterparties ~~revenues~~include ~~for~~cooperatives, ~~natural~~municipalities, ~~gas delivery~~residential, ~~service~~commercial ofand ~~$32~~industrial ~~million~~customers, power marketers, MISO, PJM and investor-owned utilities, including Ameren Illinois. ~~The~~Illinois ~~revenue~~law ~~increase~~allows ~~was~~municipalities ~~based~~and counties to negotiate the purchase price of electricity on abehalf 9of residential and small business utility customers.~~06%~~ ~~return~~In on2012, ~~equity~~Marketing Company began serving those Illinois municipalities electing to aggregate their residential and small commercial electric supply load, aand ~~capital~~which ~~structure~~selected ~~composed~~Marketing ofCompany 53as their provider.3% ~~common~~For ~~equity~~additional information on Marketing Company’s hedging activities, see Outlook in Management’s Discussion and aAnalysis ~~rate~~ of Financial Condition and Results of Operations under

base of approximately $1 billion. The rate order was based on a 2012 future test year. The rate changes became effective on January 20, 2012. In February 2012, the ICC denied rehearing requests by Ameren Illinois and an intervenor related to the granted return on equity. 8

IfTable ~~certain~~of criteria are met, Ameren Illinois’ natural gas rates may be adjusted without a traditional rate proceeding. PGA clauses permit prudently incurred natural gas costs to be passed directly to the consumer. Also, Ameren Illinois has approval from the ICC to use cost recovery mechanisms for energy efficiency programs and bad debt expense not recovered in base rates. Contents

For additional information on Illinois rate matters, including the IEIMA and the ICC’s January 2012 natural gas rate order, see Results of Operations and Outlook in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, ~~Quantitative~~ and ~~Qualitative Disclosures About Market Risk under Part II, Item 7A, and~~ Note 27 – ~~Rate~~Derivative ~~and~~Financial ~~Regulatory~~Instruments ~~Matters, and Note 15 – Commitments and Contingencies~~ under Part II, Item 8, of this report.

~~Merchant~~General ~~Generation~~Regulatory Matters

~~Merchant Generation~~Ameren ~~revenues~~Missouri, ~~are~~Ameren ~~determined by market conditions and contractual arrangements. We expect the Merchant Generation fleet of assets to have 5~~Illinois,~~503~~ ~~megawatts of capacity available for the 2012 peak summer electrical demand. This capacity reflects the closure of the four units at~~ Genco~~’s Meredosia and Hutsonville energy centers and the sale of the Columbia CT during 2011~~, ~~as well as the sale of the Medina Valley energy center in early 2012. As discussed below, Genco and~~ AERG ~~sell all of their power~~ and ~~capacity to~~ Marketing Company ~~through~~must ~~power~~receive ~~supply~~FERC ~~agreements.~~approval ~~Marketing Company attempts~~ to ~~optimize~~enter ~~the~~into ~~value~~various ~~of those assets and to mitigate risks through a variety of hedging techniques~~transactions, including ~~wholesale~~to ~~sales~~issue ofshort-term ~~capacity~~debt securities and ~~energy,~~ ~~retail~~to ~~sales~~conduct incertain ~~the non-rate-regulated Illinois market~~acquisitions, ~~spot market sales primarily in MISO and PJM~~mergers, and ~~financial~~consolidations ~~transactions,~~involving ~~including~~electric ~~options~~utility ~~and~~holding ~~other~~companies ~~derivatives.~~having ~~Marketing~~a ~~Company~~value ~~enters~~in ~~into~~excess ~~long-term~~of ~~and short-term contracts~~$10 million. ~~Marketing~~ ~~Company’s~~In ~~counterparties include cooperatives~~addition, ~~municipalities,~~these ~~residential,~~Ameren ~~commercial and industrial customers, power marketers, MISO, PJM and investor-owned~~ utilities, ~~including~~must ~~Ameren~~receive ~~Illinois.~~authorization ~~For~~from ~~additional~~the ~~information~~applicable ~~on Marketing~~state ~~Company’s~~public ~~hedging~~utility ~~activities~~regulatory ~~and~~agency ~~Marketing Company’s sales~~ to ~~Ameren~~issue ~~Illinois,~~stock ~~see Outlook in Management’s Discussion~~ and ~~Analysis~~long-term ofdebt ~~Financial~~securities ~~Condition~~(with ~~and~~maturities ~~Results~~ of ~~Operations~~more ~~under~~than ~~Part~~12 ~~II,~~months) ~~Item 7~~ and ~~Note~~to 7conduct ~~– Derivative~~mergers, ~~Financial~~affiliate ~~Instruments~~transactions, and ~~Note~~various 14other ~~– Related Party Transactions under Part II, Item 8, of this report~~activities.

8Ameren Missouri, Ameren Illinois, Genco, AERG and ATXI are also subject to mandatory reliability standards, including cybersecurity standards, adopted by FERC to ensure the reliability of the bulk power electric system. These standards are developed and enforced by NERC pursuant to authority given to it by the FERC. If Ameren or its subsidiaries were found not to be in compliance with any of these mandatory reliability standards, they could incur substantial monetary penalties and other sanctions.

~~Table~~Under PUHCA 2005, FERC and any state public utility regulatory agencies may access books and records of ~~Contents~~Ameren and its subsidiaries that are determined to be relevant to costs incurred by Ameren’s rate-regulated subsidiaries with respect to jurisdictional rates. PUHCA 2005 also permits the MoPSC and the ICC to request that FERC review cost allocations by Ameren Services to other Ameren companies.

~~General~~Operation ~~Regulatory~~of ~~Matters~~Ameren Missouri’s Callaway energy center is subject to regulation by the NRC. Its facility operating license expires on June 11, 2024. In December 2011, Ameren Missouri submitted a license extension application with the NRC to extend the energy center's operating license to 2044. There is no date by which the NRC must act on this relicensing request. Ameren Missouri’s Osage hydroelectric energy center and Ameren Missouri’s Taum Sauk pumped-storage hydroelectric energy center, as licensed projects under the Federal Power Act, are subject to FERC regulations affecting, among other things, the general operation and maintenance of the projects. The license for Ameren Missouri’s Osage hydroelectric energy center expires on March 30, 2047. In June 2008, Ameren Missouri filed a relicensing application with FERC to operate its Taum Sauk pumped-storage hydroelectric energy center for another 40 years. The existing FERC license expired on June 30, 2010. On July 2, 2010, Ameren Missouri received a license extension that allows Taum Sauk to continue operations until FERC issues a new license. FERC is reviewing the relicensing application. A FERC order is expected in 2013 or 2014. Ameren Missouri cannot predict the ultimate outcome of the order. Ameren Missouri’s Keokuk energy center and its dam in the Mississippi River between Hamilton, Illinois, and Keokuk, Iowa are operated under authority granted by an Act of Congress in 1905.

~~Ameren~~For ~~Missouri~~additional ~~and~~information ~~Ameren~~on ~~Illinois~~regulatory ~~must receive FERC approval to enter into various transactions~~matters, ~~including~~see toNote ~~issue~~2 ~~short-term debt securities and to conduct certain~~

~~acquisitions,~~– ~~mergers,~~Rate and ~~consolidations~~Regulatory ~~involving~~Matters, ~~electric~~Note ~~utility~~10 ~~holding~~- ~~companies~~Callaway ~~having~~Energy ~~a value in excess of $10 million. In addition~~Center, ~~these~~and ~~Ameren utilities~~Note ~~must~~15 ~~receive~~– ~~authorization~~Commitments ~~from~~and ~~the~~Contingencies ~~applicable~~under ~~state~~Part ~~public~~II, ~~utility~~Item 8, ~~regulatory~~of ~~agency~~this toreport, ~~issue~~which ~~stock~~include ~~and~~a ~~long-term~~discussion ~~debt~~about ~~securities~~the ~~(with~~December ~~maturities~~2005 breach of ~~more~~the ~~than~~upper 12reservoir ~~months)~~at ~~and~~Ameren toMissouri’s ~~conduct~~Taum ~~mergers,~~Sauk ~~affiliate~~pumped-storage ~~transactions,~~hydroelectric ~~and~~energy ~~various other~~ center.

~~activities.~~Environmental ~~Genco and AERG are subject to FERC’s jurisdiction when they issue any securities and when they enter into certain other transactions, including those listed above.~~ Matters

~~Ameren~~Certain ~~Missouri~~of our operations are subject to federal, ~~Ameren~~state, ~~Illinois~~and local environmental statutes or regulations relating to the safety and health of personnel, ~~ATXI~~the public, ~~Genco~~and the environment. These environmental statutes and ~~AERG~~regulations ~~are~~include ~~also~~requirements ~~subject~~for toidentification, ~~mandatory~~generation, ~~reliability standards~~storage, ~~including~~handling, ~~cybersecurity~~transportation, disposal, recordkeeping, labeling, reporting, and emergency response in connection with hazardous and toxic materials; safety and health standards; and environmental protection requirements, ~~adopted~~including bystandards ~~FERC~~and limitations relating to ~~ensure~~the discharge of air and water pollutants, the ~~reliability~~protection of natural and cultural resources, and the ~~bulk~~management ~~power~~of ~~electric~~waste ~~system~~and byproduct materials. ~~These~~Failure ~~standards~~to ~~are~~comply ~~developed~~with ~~and~~those ~~enforced~~statutes byor ~~NERC~~regulations ~~pursuant~~could tohave ~~authority~~material ~~given~~adverse effects on us. We could be subject to itcriminal or civil penalties by ~~the~~regulatory ~~FERC.~~agencies Ifor ~~the~~we ~~Ameren~~could ~~Companies~~be ~~were found~~ordered ~~not~~by the courts to bepay inprivate ~~compliance~~parties. ~~with~~Except ~~any~~as ofindicated ~~these~~in ~~mandatory~~this ~~reliability~~report, ~~standards~~we ~~they~~believe ~~may~~that ~~incur~~we ~~substantial~~are ~~monetary~~in ~~penalties~~material ~~and~~compliance ~~other~~with ~~sanctions.~~existing statutes and regulations.

~~Under~~In ~~PUHCA~~addition ~~2005,~~to ~~FERC~~existing laws and ~~any~~regulations, ~~state~~including ~~public~~the Illinois MPS that applies to AER's energy centers in Illinois, the EPA is developing environmental regulations that will have a significant impact on the electric utility ~~regulatory~~industry. ~~agencies~~These ~~may~~regulations ~~access~~could ~~books~~be particularly burdensome for certain companies, including Ameren, Ameren Missouri, Genco, and ~~records~~AERG, that operate coal-fired energy centers. Significant new rules proposed or promulgated since the beginning of ~~Ameren~~2010 include the regulation of greenhouse gas emissions; revised national ambient air quality standards for SO2 and ~~its~~NO2 ~~subsidiaries~~emissions; the CSAPR, which would have required further reductions of SO2 emissions, NOx emissions, and fine particulate matter emissions from energy centers; a regulation that ~~are~~governs ~~determined~~management of CCR and coal ash impoundments; the MATS, which require reduction of emissions of mercury, toxic metals, and acid gases from energy centers; revised NSPS for particulate matter, SO2, and NOx emissions from new sources; and new regulations under the Clean Water Act that could require significant capital expenditures, such as for new water intake structures or cooling towers, at our energy centers. The EPA has proposed CO2 limits for new coal-fired and natural gas-fired combined cycle units and is expected to propose limits for existing units in the future. These new and proposed regulations, if adopted, may be ~~relevant~~challenged tothrough ~~costs~~litigation, ~~incurred~~so their ultimate implementation as well as the timing of any such implementation is uncertain, as evidenced by ~~Ameren’s rate-regulated~~the ~~subsidiaries~~CSAPR ~~with~~being ~~respect~~vacated and remanded back to ~~jurisdictional~~the ~~rates~~EPA by the United States Court of Appeals for the District of Columbia in August 2012. ~~PUHCA~~Although ~~2005~~many ~~also~~details ~~permits~~of these future regulations are unknown, the ~~MoPSC~~combined ~~and~~effects of the ~~ICC~~new toand ~~request~~proposed ~~that~~environmental ~~FERC~~regulations ~~review~~may ~~cost~~result ~~allocations~~in bysignificant ~~Ameren~~capital ~~Services~~expenditures and/or increased operating costs over the next five to ~~other~~ten years for Ameren, ~~companies~~Ameren Missouri and AER. Compliance

Operation of Ameren Missouri’s Callaway energy center is subject to regulation by the NRC. Its facility operating license expires on June 11, 2024. In December 2011, Ameren Missouri submitted a license extension application with the NRC to extend the plant’s operating license to 2044. There is no date by which the NRC must act on this relicensing request. Ameren Missouri’s Osage hydroelectric energy center and Ameren Missouri’s Taum Sauk pumped-storage hydroelectric energy center, as licensed projects under the Federal Power Act, are subject to FERC regulations affecting, among other things, the general operation and maintenance of the projects. The license for Ameren Missouri’s Osage hydroelectric energy center expires on March 30, 2047. In June 2008, Ameren Missouri filed a relicensing application with FERC to operate its Taum Sauk pumped-storage hydroelectric energy center for another 40 years. The existing FERC license expired on June 30, 2010. On July 2, 2010, Ameren Missouri received a license extension that allows Taum Sauk to continue operations until FERC issues a new license. FERC is reviewing the relicensing application. A FERC order is expected in 2012 or 2013. Ameren Missouri cannot predict the ultimate outcome of the order. Ameren Missouri’s Keokuk energy center and its dam, in the Mississippi River between Hamilton, Illinois, and Keokuk, Iowa, are operated under authority granted by an Act of Congress in 1905. 9

~~For~~Table ~~additional information on regulatory matters, see Note 2 – Rate and Regulatory Matters and Note 15 – Commitments and Contingencies under Part II, Item 8,~~ of ~~this report, which include a discussion about the December 2005 breach of the upper reservoir at Ameren Missouri’s Taum Sauk pumped-storage hydroelectric energy center.~~ Contents

~~Environmental~~with ~~Matters~~these environmental laws and regulations could be prohibitively expensive. If they are, these regulations could require us to close or to significantly alter the operation of our energy centers, which could have an adverse effect on our results of operations, financial position, and liquidity, including the impairment of long-lived assets. Failure to comply with environmental laws and regulations might also result in the imposition of fines, penalties, and injunctive measures.

~~Certain of~~The ~~our~~decision ~~operations~~to ~~are~~make ~~subject~~pollution tocontrol ~~federal,~~equipment ~~state,~~investments ~~and~~at ~~local~~our ~~environmental~~Merchant ~~statutes~~Generation orbusiness ~~regulations~~depends ~~relating~~on towhether the ~~safety~~expected ~~and~~future ~~health~~market ofprice ~~personnel,~~for ~~the~~power ~~public,~~reflects ~~and~~ the ~~environment.~~increased ~~These~~cost for environmental ~~statutes~~compliance. ~~and~~During ~~regulations~~early ~~include requirements for identification~~2012, ~~generation,~~the ~~storage,~~observable ~~handling,~~market ~~transportation,~~price ~~disposal,~~for ~~recordkeeping,~~power ~~labeling,~~for ~~reporting,~~delivery ~~and emergency response~~ in ~~connection~~that ~~with~~year ~~hazardous~~ and ~~toxic~~in ~~materials;~~future ~~safety~~years ~~and~~sharply ~~health~~declined ~~standards;~~below ~~and~~2011 ~~environmental~~levels ~~protection requirements,~~primarily ~~including~~because ~~standards~~of ~~and~~declining ~~limitations~~natural ~~relating~~gas toprices, ~~the~~as ~~discharge~~well ofas ~~air~~the ~~and~~impact ~~water~~from ~~pollutants and~~ the ~~management~~stay of ~~waste~~the ~~and byproduct materials~~CSAPR. ~~Failure~~As toa ~~comply~~result ~~with~~of ~~those~~this ~~statutes~~sharp ordecline ~~regulations~~in ~~could have material adverse effects on us. We could be subject to criminal or civil penalties by regulatory agencies or we could be ordered by~~ the ~~courts~~market toprice ~~pay~~for ~~private~~power, ~~parties.~~as ~~Except~~well as ~~indicated~~uncertain inenvironmental ~~this report~~regulations, weGenco ~~believe~~decelerated ~~that~~the weconstruction ~~are~~of intwo ~~material~~scrubbers ~~compliance~~at ~~with~~its ~~existing~~Newton ~~statutes~~energy ~~and regulations~~center.

InFor ~~addition~~additional todiscussion ~~existing~~of ~~laws~~environmental ~~and regulations~~matters, including ~~the Illinois MPS~~NOx, ~~which govern our facilities~~SO2, ~~the~~and ~~EPA~~mercury isemission ~~developing~~reduction ~~numerous new environmental regulations that will have a significant impact on the electric utility industry. These regulations could be particularly burdensome for certain companies~~requirements, ~~including~~remediation ~~Ameren~~efforts, ~~Ameren Missouri~~ and ~~Genco,~~a ~~that~~discussion ~~operate coal-fired energy centers. Significant new rules proposed or promulgated since the beginning~~ of ~~2010 include~~ the ~~regulation~~EPA’s ofallegations ~~greenhouse gas emissions; revised national ambient air quality standards for SO2 and NO2 emissions; the CSAPR, which requires further reduction~~ of ~~SO2~~violations ~~and NOx emissions from power plants; a regulation governing management~~ of ~~CCR and coal ash impoundments;~~ the ~~MATS,~~Clean ~~which~~Air ~~reduces~~Act ~~emissions~~and ofMissouri ~~mercury,~~law ~~metals,~~in ~~and~~connection ~~acid~~with ~~gases~~projects ~~from~~at ~~power~~Ameren ~~plants;~~Missouri's ~~revised~~Rush ~~NSPS~~Island ~~for~~energy ~~particulate matter~~center, ~~SO2,~~ and ~~NOx~~ ~~emissions from new sources; and new regulations under~~ the ~~Clean~~EPA's ~~Water~~Notice ~~Act that~~of ~~could~~Violation ~~require~~of ~~significant~~permitting ~~capital~~requirements ~~expenditures such as new water intake structures or cooling towers~~ at ~~our~~Genco's Newton energy ~~centers. The EPA also plans to propose an additional rule~~center, ~~applicable~~see toLiquidity ~~new~~ and ~~existing~~Capital ~~electric~~Resources ~~generating~~in ~~units,~~Management’s ~~governing NSPS~~Discussion and ~~emission~~Analysis ~~guidelines~~of ~~for~~Financial ~~greenhouse~~Condition ~~gas~~and ~~emissions.~~Results ~~These new regulations may be litigated, so the timing~~ of ~~their~~Operations ~~implementation~~under isPart ~~uncertain~~II, ~~as evidenced by the stay of the CSAPR by the United States Court of Appeals for the District of Columbia on December~~Item 307, ~~2011. Although many details of these future regulations are unknown, the combined effects of the new~~ and ~~proposed~~Note ~~environmental~~15 ~~regulations~~– ~~may~~Commitments ~~result in significant capital expenditures~~ and~~/or~~ ~~increased~~Contingencies ~~operating~~under ~~costs over~~Part ~~the~~II, ~~next five to ten years for Ameren~~Item 8, ~~Ameren~~of ~~Missouri~~this ~~and Genco~~report. ~~Actions required to ensure that our~~

9TRANSMISSION AND SUPPLY OF ELECTRIC POWER

~~Table~~Ameren owns an integrated transmission system that comprises the transmission assets of ~~Contents~~Ameren Missouri, Ameren Illinois and ATXI. Ameren also operates two balancing authority areas, AMMO (which includes Ameren Missouri), and AMIL (which includes Ameren Illinois, ATXI, AERG, and Genco excluding EEI and Genco’s Elgin CT energy center). During 2012, the peak demand was 8,868 megawatts in AMMO and 9,720 megawatts in AMIL. The Ameren transmission system directly connects with 15 other balancing authority areas for the exchange of electric energy.

~~facilities~~Ameren Missouri, Ameren Illinois and ~~operations~~ATXI are intransmission-owning ~~compliance~~members of MISO. Transmission service on the Ameren transmission system is provided pursuant to the terms of the MISO OATT on file with ~~environmental~~FERC. ~~laws~~EEI operates its own balancing authority area and ~~regulations~~its ~~could~~own betransmission ~~prohibitively~~facilities ~~expensive~~in southern Illinois. IfThe ~~they~~EEI transmission system is directly connected to the transmission systems of MISO, the Tennessee Valley Authority, and Louisville Gas and Electric Company. EEI’s energy centers are dispatched separately from those of Ameren Missouri, ~~these~~Genco ~~regulations~~and ~~could~~AERG. Ameren ~~require~~Missouri usis authorized by the MoPSC to participate in MISO, subject to certain conditions, through May 2016.

~~close~~In orMay to2011 ~~significantly~~FERC ~~alter~~approved transmission rate incentives for the ~~operation~~Illinois ofRivers ~~our~~project, ~~energy~~which is being developed by ATXI. In December 2011, MISO approved the Illinois Rivers project as well as the Spoon River and Mark Twain projects. The total investment in these three MISO-approved projects is expected to be more than $1.3 billion from 2013 to 2019. These projects are located primarily in Illinois and Missouri.

~~centers~~In February 2012, ~~which~~FERC ~~could~~approved ~~have~~ATXI's anrequest ~~adverse~~for ~~effect~~a onforward-looking ~~our~~rate ~~results~~calculation ofwith ~~operations,~~an ~~financial~~annual ~~position~~reconciliation adjustment, ~~and~~as ~~liquidity,~~well ~~including~~as ~~the~~ATXI's ~~impairment~~request for implementation of ~~plant~~the ~~assets.~~incentives ~~Failure~~FERC ~~to comply~~approved ~~with~~in ~~environmental~~its ~~laws~~May ~~and~~2011 ~~regulations~~order ~~might~~for ~~also~~the ~~result~~Illinois inRivers ~~the~~project. ~~imposition~~In ofNovember ~~fines~~2012, ~~penalties,~~FERC approved transmission rate incentives for the Spoon River project and ~~injunctive~~the ~~measures~~Mark Twain project. FERC also approved a forward-looking rate calculation with an annual reconciliation adjustment for Ameren Illinois' electric transmission business.

~~For~~The ~~additional~~Ameren ~~discussion~~Companies and EEI are members of ~~environmental~~SERC. ~~matters~~SERC is responsible for the bulk electric power supply system in all or portions of Missouri, ~~including~~Illinois, ~~NOx~~Arkansas, ~~SO2~~Kentucky, ~~and~~Tennessee, ~~mercury~~North ~~emission~~Carolina, ~~reduction requirements~~South Carolina, ~~global~~Georgia, ~~climate~~Mississippi, ~~change~~Alabama, ~~remediation~~Louisiana, ~~efforts~~Virginia, Florida, Oklahoma, Iowa, and Texas. As a ~~discussion~~result of the ~~EPA’s~~Energy ~~allegations~~Policy Act of ~~violations~~2005, owners and operators of the ~~Clean~~bulk ~~Air~~electric ~~Act~~power ~~and~~system ~~Missouri~~are ~~law~~subject into ~~connection~~mandatory ~~with~~reliability ~~projects~~standards atpromulgated ~~certain~~by ~~coal-fired~~NERC ~~energy~~and ~~centers,~~its ~~see~~regional ~~Liquidity~~entities, ~~and~~such ~~Capital Resources~~as inSERC, ~~Management’s~~which ~~Discussion~~are ~~and~~enforced ~~Analysis~~by ofFERC. ~~Financial~~The ~~Condition~~Ameren ~~and~~Companies ~~Results~~must ofcomply ~~Operations~~with ~~under~~these ~~Part II~~standards, ~~Item 7,~~which ~~and~~are ~~Note~~in 15place –to ~~Commitments~~ensure ~~and~~the ~~Contingencies~~reliability ~~under~~of ~~Part~~the ~~II,~~bulk ~~Item 8,~~electric ofpower ~~this report~~system.

~~TRANSMISSION~~See ~~AND~~Note ~~SUPPLY~~2 OF– ~~ELECTRIC~~Rate ~~POWER~~and Regulatory Matters under Part II, Item 8, of this report for additional information.

Ameren ~~owns an integrated transmission system that comprises the transmission assets of Ameren~~ Missouri, Ameren Illinois and ATXI. Ameren also operates two balancing authority areas, AMMO (which includes Ameren Missouri), and AMIL (which includes Ameren Illinois, ATXI, Genco excluding EEI and Genco’s Elgin CT facility, and AERG). During 2011, the peak demand was 8,831 megawatts in AMMO and 9,605 megawatts in AMIL. The Ameren transmission system directly connects with 15 other balancing authority areas for the exchange of electric energy.

Ameren Missouri,’s ~~Ameren~~electric ~~Illinois~~supply ~~and ATXI~~is ~~are~~obtained ~~transmission-owning~~primarily ~~members~~from ofits ~~MISO~~own generation. ~~Transmission~~Factors ~~service~~that oncould ~~the~~cause Ameren ~~transmission~~Missouri ~~systems is provided pursuant~~ to ~~the~~purchase ~~terms~~power ofinclude, ~~the~~among ~~MISO~~other ~~OATT~~things, onabsence ~~file~~of ~~with~~sufficient ~~FERC.~~owned ~~EEI~~generation, ~~operates~~energy ~~its~~center ~~own~~outages, ~~balancing~~the ~~authority~~fulfillment ~~area~~of ~~and~~renewable ~~its~~energy ~~own~~portfolio ~~transmission facilities~~requirements, inthe ~~southern~~failure ~~Illinois.~~of ~~The~~suppliers ~~EEI~~to ~~transmission~~meet ~~system~~their ispower ~~directly~~supply ~~connected to MISO~~obligations, ~~the~~extreme ~~Tennessee~~weather ~~Valley Authority~~conditions, and ~~Louisville~~the ~~Gas~~availability ~~and~~of ~~Electric~~power ~~Company.~~at ~~EEI’s~~a ~~generating~~cost ~~units~~lower ~~are~~than ~~dispatched~~the ~~separately~~cost ~~from those~~ of ~~Ameren~~generating ~~Missouri, Genco and AERG~~it.

~~FERC,~~Ameren inMissouri continues to evaluate its ~~order~~longer-term ~~issued~~needs infor ~~May~~new ~~2011,~~baseload ~~approved~~and ~~transmission~~peaking electric generation capacity. The MoPSC's December 2012 electric rate ~~incentives~~order ~~for~~approved ~~the~~Ameren ~~Illinois~~Missouri's ~~Rivers~~implementation ~~project~~of ~~and~~MEEIA ~~the Big~~megawatthour ~~Muddy~~savings ~~project~~targets, ~~which~~energy ~~will~~efficiency beprograms, ~~developed~~and byassociated ~~ATXI~~cost orrecovery ~~ATX~~mechanisms and incentive awards. InThe ~~December~~order ~~2011,~~allows ~~MISO~~for ~~approved~~Ameren ~~the~~Missouri ~~Illinois~~to ~~Rivers~~collect ~~project~~its asprogram ~~well~~costs asand 90% of its projected lost revenue from customers over the ~~Spoon~~same ~~River~~three-year ~~and~~period ~~Mark~~starting ~~Twain~~on ~~projects~~January 2, 2013. The ~~total~~remaining ~~investment~~10% inof ~~these~~projected ~~three~~lost ~~MISO-approved~~revenue ~~projects~~ is expected to be ~~more~~ ~~than~~recovered ~~$1.2~~as ~~billion~~part ~~through~~of ~~2019,~~future ~~with~~rate ~~potential~~proceedings. ~~investment~~The ofpotential ~~approximately~~need ~~$750 million~~for ~~from~~new ~~2012~~generating toplant ~~2016.~~construction ~~All~~is ~~four~~dependent ~~projects~~on ~~are~~several inkey ~~Missouri~~factors ~~and~~including: ~~Illinois.~~continuation ~~Construction~~of ~~will~~energy ~~begin~~efficiency ~~first~~programs onbeyond ~~the~~2015, ~~Illinois~~load ~~Rivers~~growth, ~~project.~~customer ~~The~~participation ~~Big~~in ~~Muddy~~energy ~~project is~~efficiency ~~currently~~programs, ~~being~~and ~~evaluated~~the potential for ~~inclusion~~more instringent ~~MISO’s~~environmental ~~2012~~regulation ~~expansion~~of ~~plan.~~ coal-

~~The Ameren Companies and EEI are members of SERC. SERC is responsible for the bulk electric power supply~~ 10

~~system~~Table ~~in all or portions~~ of Missouri, Illinois, Arkansas, Kentucky, Tennessee, North Carolina, South Carolina, Georgia, Mississippi, Alabama, Louisiana, Virginia, Florida, Oklahoma, Iowa, and Texas. As a result of the Energy Policy Act of 2005, owners and operators of the bulk electric power system are subject to mandatory reliability standards promulgated by NERC and its regional entities, such as SERC, which are enforced by FERC. The Ameren Companies must follow these standards, which are in place to ensure the reliability of the bulk electric power system. Contents

~~See~~fired ~~Note 2~~energy –centers, ~~Rate~~which could lead to the retirement of current baseload assets. Because of the significant time required to plan, acquire permits for, and ~~Regulatory~~build ~~Matters~~a ~~under~~baseload ~~Part~~power IIplant, ~~Item 8~~Ameren Missouri continues to study future plant alternatives and is taking steps to preserve options to meet future demand. These steps include evaluating the potential for further energy efficiency programs in the long term, evaluating potential sites for natural gas-fired generation, and pursuing DOE funds through a partnership with Westinghouse for development of ~~this~~small ~~report~~modular reactor technology for ~~additional~~nuclear ~~information~~power. Ameren Missouri's next Integrated Resource Plan filing with the MoPSC is due October 1, 2014.

~~Ameren~~See ~~Missouri~~also Outlook in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, and Note 2 – Rate and Regulatory Matters and Note 15 – Commitments and Contingencies under Part II, Item 8, of this report.

Ameren Missouri’s electric supply is obtained primarily from its own generation. Factors that could cause Ameren Missouri to purchase power include, among other things, absence of sufficient owned generation, energy center outages, the fulfillment of renewable energy portfolio requirements, the failure of suppliers to meet their power supply obligations, extreme weather conditions, and the availability of power at a cost lower than the cost of generating it. Illinois

~~Ameren~~Any ~~Missouri~~electric ~~continues~~supply topurchased ~~evaluate~~by ~~its~~Ameren ~~longer-term~~Illinois ~~needs~~ for ~~new~~its ~~baseload~~retail ~~and~~customers ~~peaking~~comes ~~electric~~either ~~generation~~through ~~capacity.~~an ~~Ameren~~annual ~~Missouri’s~~procurement ~~integrated~~process ~~resource~~conducted ~~plan~~by ~~filed with~~ the ~~MoPSC~~IPA inor ~~February~~through ~~2011~~markets ~~included~~operated ~~the~~by ~~expectation that new baseload generation capacity would be required between 2020 and 2030~~MISO. ~~Because~~ ofThe ~~the significant time required to plan, acquire permits for, and build a baseload~~ power plant, Ameren Missouri continues to study future plant alternatives, as well as energy efficiency programs that could help defer new plant construction. To prepare for the long-term need for baseload capacity, and torelated ~~prepare~~procurement ~~for~~costs ~~potentially~~incurred ~~more~~by ~~stringent environmental regulation of coal-fired energy centers, which could lead to the retirement of current baseload assets,~~ Ameren ~~Missouri~~ isIllinois ~~taking~~are ~~steps~~passed todirectly ~~preserve options~~ to meet future demand. These steps include seeking improvements in regulatory treatment of energy efficiency investments, evaluating potential sites for natural gas-fired generation, and pursuing an early site permit for an additional unit at its ~~existing~~customers ~~nuclear~~through ~~plant site. Ameren Missouri’s pursuit of an early site permit is dependent upon enactment of~~ a ~~legislative framework ensuring~~ cost recovery. mechanism.

~~See~~The ~~also~~IPA ~~Outlook~~administers ina ~~Management’s~~RFP ~~Discussion~~process ~~and~~that ~~Analysis~~procures ofAmeren ~~Financial~~Illinois’ ~~Condition~~expected ~~and~~supply ~~Results~~obligation. ofSince ~~Operations~~the ~~under~~RFP ~~Part~~process ~~II,~~began ~~Item 7~~in 2009, ~~and Note~~the 2ICC –has ~~Rate~~approved ~~and~~the ~~Regulatory~~outcomes ~~Matters~~of ~~and~~multiple ~~Note~~electric 15power –procurement ~~Commitments~~RFPs ~~and~~for ~~Contingencies~~energy, ~~under~~capacity, ~~Part~~and ~~II,~~renewable ~~Item 8,~~energy ofcredits ~~this~~covering ~~report.~~different time periods.

A portion of the electric power supply required for Ameren Illinois to satisfy its distribution customers’ requirements is

~~Any electric supply~~ purchased byin ~~Ameren~~the ~~Illinois~~RFP ~~for~~process ~~its~~administered ~~retail~~by ~~customers~~the ~~comes~~IPA ~~either~~from ~~through~~Marketing anCompany, ~~annual~~on ~~procurement process~~behalf ~~conducted~~of byGenco ~~the~~and ~~IPA~~AERG, orand ~~through~~from Ameren Missouri.

10Under Illinois law, transmission and distribution service rates are regulated, while electric customers are allowed to purchase generation from an alternative retail electric supplier. At December 31, 2012, approximately 396,000 retail customers representing approximately 61% of Ameren Illinois' annual retail kilowatthour sales had elected to purchase their electricity from an alternative retail electric supplier. Customers who receive electricity from an alternative retail electric supplier continue to pay a delivery charge to Ameren Illinois for the distribution services they receive from Ameren Illinois.

~~Table~~See Note 2 – Rate and Regulatory Matters, Note 14 – Related Party Transactions and Note 15 – Commitments and Contingencies under Part II, Item 8, of ~~Contents~~this report for additional information on power procurement in Illinois.

~~markets~~Merchant ~~operated by MISO. The power and related~~ Generation

~~procurement~~Genco ~~costs~~and ~~incurred~~AERG have entered into power supply agreements with Marketing Company whereby Genco and AERG sell, and Marketing Company purchases, all of the capacity and energy available from Genco’s and AERG’s energy centers. These power supply agreements continue through December 31, 2022, and from year to year thereafter unless either party elects to terminate the agreement by ~~Ameren~~providing ~~Illinois~~the ~~are passed~~other ~~directly~~party with no less than six months’ advance written notice. EEI and Marketing Company have entered into a power supply agreement for EEI to sell all of its ~~customers~~capacity ~~through~~and aenergy ~~cost~~to ~~recovery~~Marketing ~~mechanism~~Company. This agreement expires on May 31, 2016. All of Genco’s, AERG’s and EEI’s energy centers compete for the sale of energy and capacity in the competitive energy markets through Marketing Company.

~~The~~POWER IPA administers a RFP process that procures Ameren Illinois’ expected supply obligation. Since the start of this process, the ICC has approved the outcomes of multiple electric power procurement RFPs for energy, capacity, and renewable energy credits covering different time periods. GENERATION

The following table presents the source of electric generation, excluding purchased power, for the years ended December 31, 2012, 2011 and 2010:

A portion of the electric power supply required for Ameren Illinois to satisfy its distribution customers’ requirements is purchased in the RFP process administered by the IPA from Marketing Company on behalf of Genco and AERG. In addition, as part of the 2007 Illinois Electric Settlement Agreement, Ameren Illinois entered into financial contracts with Marketing Company (for the benefit of Genco and AERG) to lock in energy prices for 400 to 1,000 megawatts annually of its round-the-clock power requirements during the period June 1, 2008, through December 31, 2012, at the market prices relevant at that time. These financial contracts do not include capacity, are not load-following products, and do not involve the physical delivery of energy.



	Coal		Nuclear		Natural Gas		Renewables^(a)		Oil
Ameren:^(b)
2012	81	%	15	%	3	%	1	%	(c)
2011	85		12		1		2		(c)
2010	85		12		1		2		(c)
Ameren Missouri:
2012	73	%	24	%	1	%	2	%	(c)
2011	77		19		1		3		(c)
2010	77		19		1		3		—
Merchant Generation:
2012	94	%	—		6	%	—		—
2011	98		—		2		—		(c)
2010	98		—		2		—		(c)

~~See~~(a) ~~Note~~Renewable 2power –generation ~~Rate~~includes ~~and~~production ~~Regulatory~~from ~~Matters,~~Ameren ~~Note~~Missouri's 14hydroelectric, –pumped-storage, ~~Related Party Transactions~~ and ~~Note 15~~methane –gas ~~Commitments~~energy ~~and Contingencies under Part II~~centers, ~~Item 8,~~but ofexcludes ~~this~~purchased ~~report~~renewable ~~for~~energy ~~additional information on power procurement in Illinois~~credits.

~~Merchant~~(b) ~~Generation~~Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

~~Genco~~(c) ~~and~~Less ~~AERG~~than ~~have entered~~1% ~~into power supply agreements with Marketing Company whereby Genco and AERG sell, and Marketing Company purchases, all~~ of ~~the~~total ~~capacity~~fuel ~~and energy available from Genco’s and AERG’s generation energy centers and the associated energy. These power~~ supply agreements continue through December 31, 2022, and from year to year thereafter unless either party elects to terminate the agreement by providing the other party with no less than six months’ advance written notice. EEI and Marketing Company have entered into a power supply agreement for EEI to sell all of its capacity and energy to Marketing Company. This agreement expires on May 31, 2016. All of Genco’s, AERG’s and EEI’s energy centers compete for the sale of energy and capacity in the competitive energy markets through Marketing Company. See Note 14 – Related Party Transactions under Part II, Item 8, of this report for additional information.

~~POWER GENERATION~~ 11

~~The~~Table ~~following table presents the source~~ of ~~electric generation, excluding purchased power, for the years ended December 31, 2011, 2010 and 2009:~~ Contents

	Coal			Nuclear			Natural Gas			Renewables			Oil
Ameren:(a)
2011		85	%		12	%		1	%		2	%		(b	)%
2010		85			12			1			2			(b	)
2009		83			13			1			3			(b	)
Ameren Missouri:
2011		77	%		19	%		1	%		3	%		(b	)%
2010		77			19			1			3			-
2009		75			21			(b	)		4			-
Merchant Generation:
2011		98	%		-	%		2	%		-	%		(b	)%
2010		98			-			2			-			(b	)
2009		99			-			1			-			(b	)
Genco:
2011		99	%		-	%		1	%		-	%		(b	)%
2010		99			-			1			-			(b	)
2009		100			-			(b	)		-			(b	)

The following table presents the cost of fuels for electric generation for the years ended December 31, 2012, 2011, and 2010:

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.



Cost of Fuels (Dollars per Mmbtu)	2012		2011		2010
Ameren:
Coal^(a)	$	2.081	$	1.931	$	1.848
Nuclear	0.964		0.750		0.701
Natural gas^(b)	3.772		6.097		6.539
Weighted average – all fuels^(c)	$	1.975	$	1.873	$	1.803
Ameren Missouri:
Coal^(a)	$	1.925	$	1.733	$	1.675
Nuclear	0.964		0.750		0.701
Natural gas^(b)	4.517		5.873		6.199
Weighted average – all fuels^(c)	$	1.743	$	1.610	$	1.563
Merchant Generation:
Coal^(a)	$	2.282	$	2.184	$	2.063
Natural gas^(b)	3.392		6.374		6.972
Weighted average – all fuels^(c)	$	2.359	$	2.292	$	2.169

(ba) ~~Less~~The ~~than~~fuel 1%cost for coal represents the cost of ~~total~~coal, the costs for transportation, which include railroad diesel fuel ~~supply~~additives, and the cost of emission allowances.

11(b) The fuel cost for natural gas represents the cost of natural gas and firm and variable costs for transportation, storage, balancing, and fuel losses for delivery to the plant. In addition, the fixed costs for firm transportation and firm storage capacity are included in the calculation of fuel cost for the energy centers.

~~Table~~(c) ofRepresents ~~Contents~~all costs for fuels used in our energy centers, to the extent applicable, including coal, nuclear, natural gas, methane gas, oil, propane, tire chips, paint products, and handling. Oil, propane, tire chips, and paint products are not individually listed in this table because their use is minimal.

~~The following table presents the cost of fuels for electric generation for the years ended December 31, 2011, 2010 and 2009:~~ Coal

Cost of Fuels (Dollars per million Btus)	2011		2010		2009
Ameren:
Coal(a)	$	1.931	$	1.848	$	1.654
Nuclear		0.750		0.701		0.620
Natural gas(b)		6.097		6.539		8.685
Weighted average – all fuels(c)	$	1.873	$	1.803	$	1.591
Ameren Missouri:
Coal(a)	$	1.733	$	1.675	$	1.534
Nuclear		0.750		0.701		0.620
Natural gas(b)		5.873		6.199		8.544
Weighted average – all fuels(c)	$	1.610	$	1.563	$	1.386
Merchant Generation:
Coal(a)	$	2.184	$	2.063	$	1.813
Natural gas(b)		6.374		6.972		8.796
Weighted average – all fuels(c)	$	2.292	$	2.169	$	1.934
Genco:
Coal(a)	$	2.230	$	2.112	$	1.869
Natural gas(b)		7.272		7.881		13.159
Weighted average – all fuels(c)	$	2.322	$	2.206	$	1.957

Ameren Missouri and the Merchant Generation business have agreements in place to purchase a portion of the coal they need and to transport it to energy centers through 2019. Ameren Missouri and Merchant Generation expect to enter into additional contracts to purchase coal from time to time. Coal supply agreements for Ameren Missouri have terms of up to six years, and expire between 2014 and 2017. Ameren Missouri has an ongoing need for coal to serve its native load customers, so it pursues a price hedging strategy consistent with this requirement. Merchant Generation's forward coal requirements and coal supply agreements are dependent on the volume of power sales contracted. Merchant Generation strives to achieve increased margin certainty by aligning its fuel purchases with its power sales. Ameren burned 34 million tons (Ameren Missouri – 19 million, Merchant Generation – 15 million) of coal in 2012. See Part II, Item 7A – Quantitative and Qualitative Disclosures About Market Risk of this report for additional information about coal supply contracts.

About 97% of Ameren’s coal (aAmeren Missouri – 97%, Merchant Generation – 97%) ~~The~~is ~~fuel~~purchased ~~cost~~from ~~for~~the Powder River Basin in Wyoming. The remaining coal ~~represents~~is typically purchased from the ~~cost~~Illinois Basin. Ameren Missouri and Merchant Generation have a goal to maintain coal inventory consistent with their risk management policies. Inventory may be adjusted because of changes in burn or uncertainties of supply due to potential work stoppages, delays in coal deliveries, ~~costs~~equipment ~~for~~breakdowns, ~~transportation~~and other factors. In the past, ~~which~~deliveries ~~includes~~from ~~railroad~~the ~~diesel~~Powder ~~fuel~~River ~~additives~~Basin have occasionally been restricted because of rail maintenance, weather, and ~~cost~~derailments. As of ~~emission~~December 31, ~~allowances~~2012, coal inventories for Ameren Missouri and for Merchant Generation were at or above targeted levels. Disruptions in coal deliveries could cause Ameren Missouri and Merchant Generation to pursue a strategy that could include reducing sales of power during low-margin periods, buying higher-cost fuels to

~~(b)~~generate ~~The~~required ~~fuel cost for natural gas represents the cost of natural gas and firm and variable costs for transportation~~electricity, ~~storage, balancing,~~ and ~~fuel~~purchasing ~~losses~~power ~~for~~from ~~delivery~~other ~~to the plant~~sources. ~~In addition, the fixed costs for firm transportation and firm storage capacity are included in the calculation of fuel cost for the generating facilities.~~

(c) Represents all costs for fuels used in our electric generating facilities, to the extent applicable, including coal, nuclear, natural gas, oil, propane, tire chips, paint products, and handling. Oil, paint products, propane, and tire chips are not individually listed in this table because their use is minimal.Nuclear

~~Coal~~The steps in the process to provide nuclear fuel generally involve the mining and milling of uranium ore to produce uranium concentrates, the conversion of uranium concentrates to uranium hexafluoride gas, the enrichment of that gas, and the fabrication of the enriched uranium hexafluoride gas into usable fuel assemblies. Ameren Missouri has entered into uranium, uranium conversion, uranium enrichment, and fabrication contracts to procure the fuel supply for its Callaway nuclear energy center.

~~Ameren,~~Fuel ~~Ameren~~assemblies ~~Missouri~~for ~~and~~the ~~Genco~~2013 ~~have~~spring ~~agreements~~refueling inat ~~place~~Ameren toMissouri's ~~purchase~~Callaway aenergy ~~portion~~center were ~~of their coal needs~~ manufactured and towere ~~transport~~delivered it to ~~electric~~the ~~generating~~ energy ~~centers~~center ~~through~~in ~~2019~~January 2013. Ameren, ~~Ameren~~ Missouri ~~and~~also ~~Genco~~has ~~expect~~ agreements or inventories to ~~enter~~price-hedge ~~into~~approximately ~~additional~~99%, ~~contracts~~52%, toand ~~purchase~~46% ~~coal~~of ~~from~~Callaway's ~~time~~2014, to2016 ~~time~~and 2017 refueling requirements, respectively. ~~Coal~~Ameren ~~supply~~Missouri ~~agreements~~has ~~typically~~uranium ~~have~~(concentrate anand ~~initial~~hexafluoride) ~~term~~inventories ofand upsupply contracts sufficient to ~~five~~meet ~~years,~~all ~~with~~of ~~about~~its ~~20%~~uranium ofand ~~the~~conversion ~~contracts~~requirements ~~expiring~~at ~~annually~~least through 2017. Ameren Missouri has anenriched ~~ongoing~~uranium ~~need~~inventories ~~for~~and ~~coal~~enrichment supply contracts sufficient to ~~serve~~ ~~its~~satisfy ~~native~~enrichment ~~load~~requirements ~~customers~~through ~~and~~at ~~pursues~~least a2017. ~~price~~Fuel ~~hedging~~fabrication ~~strategy~~services ~~consistent~~are ~~with~~under ~~this~~contract ~~requirement~~through 2014. Ameren ~~Merchant~~Missouri ~~Generation’s~~expects ~~forward~~to ~~coal~~enter ~~requirements~~into ~~are~~additional ~~dependent~~contracts onto ~~the~~purchase ~~volume~~nuclear offuel. ~~power~~As ~~sales~~a ~~that~~member ~~have~~of ~~been~~Fuelco, ~~contracted.~~Ameren ~~Merchant~~Missouri ~~Generation strives~~can tojoin ~~achieve~~with ~~increased~~other ~~margin~~member ~~certainty~~companies byto ~~aligning~~increase its ~~fuel~~purchasing ~~purchases~~power, ~~with~~enhance ~~its~~diversification, ~~power~~and ~~sales~~pursue opportunities for volume discounts. ~~Ameren~~The ~~burned~~Callaway ~~39 million~~energy ~~tons~~center ~~(Ameren~~normally ~~Missouri~~requires –refueling 22at ~~million,~~18-month ~~Genco~~intervals. –The ~~13 million)~~last ofrefueling ~~coal~~was completed in November 2011. ~~See~~There ~~Part~~is ~~II,~~no ~~Item 7A~~refueling ~~– Quantitative~~scheduled for 2015 and ~~Qualitative~~2018. ~~Disclosures~~The ~~About~~nuclear ~~Market~~fuel ~~Risk~~markets ofare ~~this~~competitive, ~~report~~and ~~for~~prices ~~additional~~can ~~information~~be ~~about~~volatile; ~~coal~~however, we do not anticipate any significant problems in meeting our future supply ~~contracts~~requirements.

About 98% of Ameren’s coal (Ameren Missouri – 97%, Genco – 99%) is purchased from the Powder River Basin in Wyoming. The remaining coal is typically purchased from the Illinois Basin. Ameren, Ameren Missouri and Genco have a goal to maintain coal inventory consistent with their risk management policies. Inventory may be adjusted because of changes in burn or uncertainties of supply due to potential work stoppages, delays in coal deliveries, equipment breakdowns, and other factors. In the past, deliveries from the Powder River Basin have occasionally been restricted because of rail maintenance, weather, and 12

~~derailments.~~Table As of December 31, 2011, coal inventories for Ameren Missouri were at targeted levels and were at or above targeted levels for Genco. Disruptions in coal deliveries could cause Ameren, Ameren Missouri and Genco to pursue a strategy that could include reducing sales of power during low-margin periods, buying higher-cost fuels to generate required electricity, and purchasing power from other sources. Contents

~~Nuclear~~Natural Gas Supply for Generation

~~The~~To ~~steps~~maintain indeliveries ~~the~~to ~~process~~natural ~~to provide~~gas-fired ~~nuclear~~energy ~~fuel~~centers ~~generally~~throughout ~~involve~~the year, especially during the ~~mining~~summer ~~and~~peak ~~milling~~demand, Ameren’s portfolio of ~~uranium~~natural ~~ore~~gas tosupply ~~produce~~resources ~~uranium~~includes ~~concentrates,~~firm transportation capacity and firm no-notice storage capacity leased from interstate pipelines. Ameren Missouri and Merchant Generation primarily use the ~~conversion~~interstate pipeline systems of ~~uranium~~Panhandle ~~concentrates~~Eastern toPipe ~~uranium~~Line ~~hexafluoride~~Company, ~~gas~~Trunkline Gas Company, ~~the~~Natural ~~enrichment~~Gas ofPipeline ~~that~~Company ~~gas~~of America, and ~~the~~Mississippi ~~fabrication~~River ofTransmission ~~the~~Corporation ~~enriched~~to ~~uranium hexafluoride~~transport natural gas ~~into~~to ~~usable~~energy ~~fuel assemblies~~centers. ~~Ameren~~In ~~Missouri~~addition ~~has~~to ~~entered~~physical ~~into uranium~~transactions, ~~uranium~~Ameren ~~conversion,~~uses ~~enrichment~~financial instruments, including some in the NYMEX futures market and ~~fabrication~~some ~~contracts~~in the OTC financial markets, to ~~procure~~hedge the ~~fuel~~price ~~supply~~paid for ~~its~~natural ~~Callaway nuclear plant~~gas.

~~Fuel~~Ameren ~~assemblies~~Missouri’s ~~for~~and ~~the~~Merchant ~~2013~~Generation's ~~spring~~natural ~~refueling~~gas atprocurement ~~Ameren~~strategy ~~Missouri’s~~is ~~Callaway~~designed to ensure reliable and immediate delivery of natural gas to their energy ~~center are~~centers. ~~scheduled~~This ~~for~~is ~~manufacture~~ accomplished by optimizing transportation and ~~delivery~~ storage options and minimizing cost and price risk through various supply and price-hedging agreements that allow access to ~~the~~multiple ~~plant~~gas ~~during~~pools, ~~2012~~supply basins, and storage services. As of December 31, 2012, Ameren Missouri ~~also~~had ~~has~~price-hedged ~~agreements~~about or34% ~~inventories~~and toMerchant Generation had price hedged 59% of its expected natural gas supply requirements for generation in 2013.

~~price-hedge~~Renewable ~~approximately 92%, 82%, and 47% of~~ Energy

~~Callaway’s~~Illinois ~~2013~~and Missouri have enacted laws requiring electric utilities to include renewable energy resources in their portfolios. Illinois requires renewable energy resources to equal or exceed 2% of the total electricity that each electric utility supplies to its eligible retail customers as of June 1, ~~2014~~2008, with that percentage increasing to 10% by June 1, 2015, and ~~2016~~to ~~refueling~~25% ~~requirements~~by June 1, ~~respectively~~2025. In 2012, Ameren ~~Missouri~~Illinois procured approximately 8% of its total electricity from renewable energy resources. Ameren Illinois has ~~uranium~~procured ~~(concentrate~~renewable energy credits under the IPA-administered procurement process to meet the renewable energy portfolio requirement through at least May 2017. In December 2010, Ameren Illinois entered into 20-year agreements with renewable energy suppliers and commenced receiving renewable energy credits under these agreements in June 2012. Approximately 54% of the 2013 plan year renewable energy requirement will be met through these agreements. The remaining requirement will be met through IPA procurements, which resulted in contracts that were executed in February 2012 with a term of June 2013 through December 2017.

~~and~~In ~~hexafluoride)~~Missouri, ~~inventories~~utilities ~~and~~are ~~supply~~required ~~contracts~~to purchase or generate from renewable energy sources electricity equaling at least 2% of native load sales, with that percentage increasing to at least 15% by 2021, subject to a 1% annual limit on customer rate impacts. At least 2% of each renewable energy portfolio requirement must be derived from solar energy. Ameren Missouri expects to satisfy the nonsolar requirement through 2017 with its existing renewable generation, including the Maryland Heights energy center, along with a 15-year 102-megawatt power purchase agreement with a wind farm operator in Iowa that became

~~sufficient~~effective in 2009. Currently, Ameren Missouri expects to meet ~~all~~the solar energy requirement through the purchase of ~~its~~solar-generated ~~uranium~~renewable energy credits, and ~~conversion~~generation from solar panels installed on Ameren's general office building. However, Ameren Missouri is studying other options for compliance. In 2012, Ameren Missouri purchased or generated approximately 3% of its native load sales from renewable energy resources.

~~requirements~~In ~~through~~2012, Ameren Missouri began generating power at ~~least~~its ~~2014~~Maryland Heights energy center. This ~~Ameren~~energy center, located at a landfill in Maryland Heights, Missouri, has ~~enriched~~the ~~uranium~~capability ~~inventories~~to ~~and~~generate ~~enrichment~~up to approximately 15 megawatts of electricity by burning methane gas collected from the landfill. Ameren Missouri signed a 20-year supply agreement with the landfill owner to purchase methane gas.

12Energy Efficiency

~~Table~~Ameren’s rate-regulated utilities have implemented energy efficiency programs to educate and help their customers become more efficient users of ~~Contents~~energy. The MEEIA established a regulatory framework that, among other things, allows electric utilities to recover costs related to MoPSC-approved energy efficiency programs. The law requires the MoPSC to ensure that a utility’s financial incentives are aligned to help customers use energy more efficiently, to provide timely cost recovery, and to provide earnings opportunities associated with cost-effective energy efficiency programs. Missouri does not have a law mandating energy efficiency standards.

~~contracts~~The ~~sufficient~~MoPSC's toDecember ~~satisfy~~2012 ~~enrichment~~electric ~~requirements~~rate ~~through~~order ~~2013.~~approved ~~Fuel~~Ameren ~~fabrication~~Missouri's ~~services~~implementation ~~are~~of ~~under~~MEEIA ~~contract~~megawatthour ~~through~~savings ~~2014. Ameren~~targets, ~~Missouri~~energy ~~expects~~efficiency toprograms, ~~enter~~and ~~into~~associated ~~additional~~cost ~~contracts~~recovery ~~to purchase~~mechanisms ~~nuclear~~and ~~fuel~~incentive awards. AsBeginning ain ~~member of Fuelco~~2013, Ameren Missouri ~~can~~will ~~join~~invest ~~with~~approximately ~~other~~$147 ~~member~~million ~~companies~~over tothe ~~increase~~next ~~its~~three ~~purchasing~~years ~~power, enhance diversification and pursue opportunities~~ for ~~volume~~energy ~~discounts~~efficiency programs. The ~~Callaway~~order ~~nuclear~~allows ~~plant~~for ~~normally~~Ameren ~~requires refueling~~Missouri atto ~~18-month~~collect ~~intervals.~~its ~~The~~program ~~last~~costs ~~refueling~~and ~~was~~90% ~~completed~~of inits ~~November~~projected ~~2011.~~lost ~~There~~revenue isfrom nocustomers ~~refueling~~over ~~scheduled~~the ~~for~~same ~~2012~~three ~~and~~years ~~2015.~~starting ~~The~~on ~~nuclear~~January ~~fuel markets are competitive~~2, ~~and~~2013. ~~prices~~The ~~can~~remaining be10% ~~volatile;~~of ~~however,~~projected welost dorevenue ~~not~~is ~~anticipate~~expected ~~any significant~~to ~~problems~~be inrecovered ~~meeting~~as ~~our~~part of future ~~supply~~rate ~~requirements~~proceedings.

~~Natural~~Additionally, ~~Gas~~the ~~Supply~~order provides for ~~Generation~~an incentive award that would allow Ameren Missouri to earn additional revenues based on achievement of certain energy efficiency goals, including approximately $19 million if 100% of its energy efficiency goals are achieved during the three-year period, with the potential to earn more if Ameren Missouri's energy savings exceed those goals. Ameren Missouri must achieve at least 70% of its energy efficiency goals before it earns any incentive award. The recovery of the incentive award from customers, if the energy efficiency goals are achieved, would begin after the three-year energy efficiency plan is complete and upon the effective date of an electric service rate order or possibly with the future adoption of a rider mechanism. See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for additional information.

ToIllinois ~~maintain~~has ~~gas~~enacted ~~deliveries~~a tolaw ~~gas-fired~~requiring ~~generating units throughout the year, especially during the summer peak demand,~~ Ameren’s ~~portfolio~~Illinois ~~of natural~~to ~~gas~~offer ~~supply~~energy ~~resources~~efficiency ~~includes firm transportation capacity and firm no-notice storage capacity leased from interstate pipelines~~programs. ~~Ameren~~The ~~Missouri~~law ~~and~~also ~~Genco~~allows ~~primarily~~recovery ~~use~~mechanisms ~~the interstate pipeline systems~~ of ~~Panhandle~~the ~~Eastern~~programs’ ~~Pipe Line Company, Trunkline Gas Company, Natural Gas Pipeline Company of America, and Mississippi River Transmission Corporation to transport natural gas to generating units~~costs. InThe ~~addition~~ICC tohas ~~physical~~issued ~~transactions,~~orders ~~Ameren uses financial instruments, including some in the NYMEX futures market and some in the OTC financial markets, to hedge the price paid for natural gas.~~

Ameren Missouri’s and Genco’s natural gas procurement strategy is designed to ensure reliable and immediate delivery of natural gas to their generating units. This is accomplished by optimizing transportation and storage options and minimizing cost and price risk through various supply and price-hedging agreements that allow access to multiple gas pools, supply basins, and storage services. As of December 31, 2011, Ameren Missouri had price-hedged about 12% and Genco had price-hedged 32% of its expected natural gas supply requirements for generation in 2012. 13

~~Renewable~~Table ~~Energy~~of Contents

~~Illinois~~approving ~~and~~Ameren ~~Missouri~~Illinois’ ~~have enacted laws requiring~~ electric ~~utilities~~and tonatural ~~include~~gas ~~renewable~~ energy ~~resources~~efficiency inplans ~~their~~as ~~portfolios.~~well ~~Illinois~~as ~~requires renewable~~cost ~~energy~~recovery ~~resources~~mechanisms toby ~~equal~~which orprogram ~~exceed~~costs 2%can ofbe ~~the~~recovered ~~total~~from ~~electricity that each electric utility supplies to its eligible retail~~ customers. asIn ~~of June 1~~addition, ~~2008,~~over ~~increasing~~a toten-year ~~15% by June 1~~period, ~~2015,~~Ameren ~~and~~Illinois towill ~~25%~~invest byan ~~June 1,~~estimated ~~2025.~~$625 ~~Ameren Illinois~~million ~~has~~to ~~procured~~upgrade ~~renewable~~and ~~energy~~modernize ~~credits~~its ~~under~~transmission ~~the~~and ~~IPA-administered~~distribution ~~procurement~~infrastructure ~~process~~in toaccordance ~~meet~~with the ~~renewable~~IEIMA. ~~energy~~As ~~portfolio~~part ~~requirement~~of ~~through~~these ~~May 2012. In December 2010~~upgrades, Ameren Illinois ~~entered~~expects ~~into~~to ainvest ~~20-year~~$360 million ~~agreement~~to ~~with~~install ~~renewable energy~~smart ~~suppliers~~meters, ~~and~~which ~~will~~could ~~begin~~enable ~~receiving~~customers ~~renewable energy credits under the agreement starting in June 2012,~~ to ~~help~~improve ~~supplement these requirements~~efficiency. ~~Approximately 50% of the 2012 renewable energy requirement will be met through this agreement. In 2011,~~

~~Ameren~~NATURAL ~~Illinois~~GAS ~~procured~~SUPPLY ~~approximately~~FOR ~~6% of its total electricity from renewable energy resources.~~ DISTRIBUTION

InAmeren Missouri, ~~utilities~~and ~~are~~Ameren ~~required~~Illinois toare ~~purchase~~responsible orfor ~~generate~~the ~~from~~purchase ~~renewable~~and ~~energy~~delivery ~~sources electricity equaling at least 2%~~ of ~~native~~natural ~~load~~gas ~~sales, with that percentage increasing~~ to attheir ~~least~~utility ~~15% by 2021, subject to a 1% limit on customer rate impacts~~customers. ~~At least 2% of each renewable energy portfolio requirement must be derived from solar energy.~~ Ameren Missouri expects to satisfy the nonsolar requirement through 2017 with existing renewable generation in its current fleet along with a 15-year 102 MW power purchase agreement with a wind farm operator in Iowa that became effective in 2009 and ~~the landfill gas project discussed below. Currently,~~ Ameren ~~Missouri~~Illinois ~~expects~~develop toand ~~meet~~manage ~~the~~a ~~solar~~portfolio ~~energy requirement through the purchase~~ of ~~solar-generated~~natural ~~renewable~~gas ~~energy~~supply ~~credits; however, Ameren Missouri is studying other options for compliance~~resources. InThese ~~2011,~~include ~~Ameren~~firm ~~Missouri~~gas ~~purchased or generated approximately 3% of its native load sales from renewable energy resources.~~

Insupply ~~September~~under ~~2009~~term agreements with producers, interstate and intrastate firm transportation capacity, firm storage capacity leased from interstate pipelines, and on-system storage facilities to maintain natural gas deliveries to customers throughout the year and especially during peak demand periods. Ameren Missouri ~~announced~~and anAmeren ~~agreement~~Illinois ~~with~~primarily ause ~~landfill~~Panhandle ~~owner~~Eastern toPipe ~~install~~Line ~~CTs~~Company, atTrunkline aGas ~~landfill~~Company, ~~site~~Natural ~~in Maryland~~Gas ~~Heights~~Pipeline Company of America, ~~Missouri~~Mississippi River Transmission Corporation, ~~which~~Northern isBorder ~~expected~~Pipeline toCompany, ~~generate~~and ~~approximately~~Texas 15Eastern ~~megawatts~~Transmission ofCorporation ~~electricity~~interstate bypipeline ~~burning~~systems ~~methane~~to ~~gas~~transport ~~collected~~natural ~~from~~gas ~~the~~to ~~landfill~~their systems. ~~The~~In ~~CTs~~addition ~~(known~~to astransactions requiring physical delivery, financial instruments, including those entered into in the ~~Maryland~~NYMEX ~~Heights~~futures ~~energy~~market ~~center)~~and in the OTC financial markets, are ~~expected~~used to ~~begin~~hedge ~~generating~~the ~~power~~price ~~in 2012~~paid for natural gas. See Part II, Item 7A – Quantitative and Qualitative Disclosures About Market Risk of this report for additional information about natural gas supply contracts. Natural gas purchase costs are passed on to customers of Ameren Missouri ~~signed~~and aAmeren ~~20-year~~Illinois ~~supply~~under ~~agreement~~PGA ~~with~~clauses, subject to prudency reviews by the ~~landfill~~MoPSC ~~owner~~and tothe ~~purchase~~ICC. ~~methane~~As of December 31, 2012, Ameren Missouri had price-hedged 89%, and Ameren Illinois had price-hedged 81%, of its expected natural gas. supply requirements for distribution in 2013.

For additional information on our fuel and purchased power supply, see Results of Operations, Liquidity and Capital Resources and Effects of Inflation and Changing Prices in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, of this report. Also see Quantitative and Qualitative Disclosures About Market Risk under Part II, Item 7A, of this report, Note 1 – Summary of Significant Accounting Policies, Note 7 – Derivative Financial Instruments, Note 10 – Callaway Energy ~~Efficiency~~Center, Note 14 – Related Party Transactions, and Note 15 – Commitments and Contingencies under Part II, Item 8 of this report.

~~Ameren’s~~INDUSTRY rate-regulated utilities have implemented energy efficiency programs to educate and help their customers become more efficient users of energy. The MEEIA, enacted in 2009, established a regulatory framework that, among other things, allows electric utilities to recover costs related to MoPSC-approved energy efficiency programs. The law requires the MoPSC to ensure that a utility’s financial incentives are aligned with helping customers use energy more efficiently, to provide timely cost recovery, and to provide earnings opportunities associated with cost-effective energy efficiency programs. Missouri does not have a law mandating energy efficiency standards. ISSUES

InWe ~~January~~are ~~2012,~~facing ~~Ameren~~issues ~~Missouri~~common made its initial filing with the MoPSC under the MEEIA. This filing proposes a three-year plan that includes a portfolio of energy efficiency programs along with a cost recovery mechanism. If the proposal is approved, beginning in January 2013, Ameren Missouri plans to ~~invest $145 million over three years for~~ the ~~proposed~~electric ~~energy~~and ~~efficiency~~natural ~~programs.~~gas Autility ~~decision~~industry byand the ~~MoPSC~~merchant in this proceeding is anticipated in the second quarter of 2012. Ameren Missouri anticipates that the impacts of the MoPSC’s decision in this MEEIA filing will be included in rates set under its pending electric ~~service~~generation ~~rate case that was filed on February 3, 2012, which has an anticipated true-up date of July 31, 2012~~industry. ~~Ameren~~These ~~Missouri’s~~issues ~~pending electric rate case includes an annual revenue increase of~~ include:

13• continually developing and complex environmental laws, regulations and issues, including air and water quality standards, mercury emissions standards, and likely greenhouse gas limitations and CCR management requirements;

~~Table~~• ofpolitical ~~Contents~~and regulatory resistance to higher rates;

~~$81~~• ~~million~~the ~~relating~~potential tofor ~~its~~changes ~~planned portfolio of energy efficiency programs included~~ in ~~its~~laws, ~~MEEIA~~regulations, ~~filing. See Note 2 – Rate~~ and ~~Regulatory~~policies ~~Matters~~at ~~under~~the ~~Part~~state ~~II,~~and ~~Item 8,~~federal ~~of this report for additional information.~~ level;

~~Illinois~~• ~~has~~access ~~enacted a law requiring Ameren Illinois~~ to offer energy efficiency programs. The law also allows recovery mechanisms of the programs’ costs. The ICC has issued orders approving Ameren Illinois’ electric and natural gas energy efficiency plans as well as cost recovery mechanisms by which program costs can be recovered from customers. In addition, ~~over a ten-year period, Ameren Illinois will invest an estimated $625 million to upgrade~~ and ~~modernize~~uncertainty ~~its transmission and distribution infrastructure~~ in, ~~accordance with~~ the ~~IEIMA.~~capital Asand ~~part~~credit ~~of these upgrades, Ameren Illinois expects to invest $360 million to install smart meters, which could enable customers to improve efficiency.~~ markets;

~~NATURAL~~• ~~GAS~~cybersecurity ~~SUPPLY~~risk, ~~FOR~~including ~~DISTRIBUTION~~loss of operational control of energy centers and electric and natural gas transmission and distribution systems and/or loss of data, and compliance with related industry regulations;

~~Ameren~~• ~~Missouri~~the ~~and~~potential ~~Ameren Illinois are responsible~~ for ~~the~~more ~~purchase~~intense ~~and~~competition delivery of natural gas to their gas utility customers. Ameren Missouri and Ameren Illinois develop and manage a portfolio of gas supply resources. These include firm gas supply under term agreements with producers, interstate and intrastate firm transportation capacity, firm storage capacity leased from interstate pipelines, and on-system storage facilities to maintain gas deliveries to customers throughout the year and especially during peak demand. Ameren Missouri and Ameren Illinois primarily use the Panhandle Eastern Pipe Line Company, the Trunkline Gas Company, the Natural Gas Pipeline Company of America, the Mississippi River Transmission Corporation, the Northern Border Pipeline Company, and the Texas Eastern Transmission Corporation interstate pipeline systems to transport natural gas to their systems. In addition to physical transactions, financial instruments, including those entered into in ~~the NYMEX futures market and in the OTC financial markets~~generation, ~~are used to hedge the price paid for natural gas. See Part II, Item 7A – Quantitative and Qualitative Disclosures About Market Risk of this report for additional information about natural gas~~ supply ~~contracts. Natural gas purchase costs are passed on to customers of Ameren Missouri~~ and ~~Ameren Illinois under PGA clauses~~distribution, ~~subject~~including tonew prudency reviews by the MoPSC and the ICC. As of December 31, 2011, Ameren Missouri had price-hedged 90%, and Ameren Illinois had price-hedged 87%, of its expected natural gas supply requirements for distribution in 2012. technologies;

~~For~~• ~~additional~~pressure ~~information~~ on ~~our~~customer ~~fuel~~growth and ~~purchased~~usage ~~power supply, see Results of Operations, Liquidity and Capital Resources and Effects of Inflation and Changing Prices~~ in ~~Management’s~~light ~~Discussion and Analysis~~ of ~~Financial~~current ~~Condition~~economic ~~and~~conditions ~~Results of Operations under Part II, Item 7, of this report. Also see Quantitative~~ and ~~Qualitative~~energy ~~Disclosures~~efficiency ~~About Market Risk under Part II, Item 7A, of this report, Note 1 – Summary of Significant Accounting~~ initiatives;

~~Policies,~~• ~~Note~~the 7potential –for ~~Derivative~~reregulation ~~Financial~~in ~~Instruments~~some states, ~~Note 10 –~~which ~~Callaway~~could ~~Energy~~cause ~~Center,~~electric ~~Note~~distribution 14companies –to ~~Related~~build ~~Party~~or ~~Transactions,~~acquire energy centers and ~~Note~~to 15purchase –less ~~Commitments~~power ~~and Contingencies~~from ~~under~~electric ~~Part~~generation ~~II,~~companies ~~Item 8~~such ofas ~~this~~Genco ~~report.~~and AERG;

~~INDUSTRY~~• ~~ISSUES~~changes in the structure of the industry as a result of changes in federal and state laws, including the formation and growth of independent transmission entities;

We• ~~are~~increases, ~~facing~~decreases, ~~issues~~and ~~common~~volatility toin ~~the~~power ~~electric~~prices ~~and~~due ~~natural~~to ~~gas~~the ~~utility~~balance ~~industry~~of supply and ~~the~~demand ~~merchant~~and ~~electric~~marginal ~~generation~~fuel ~~industry. These issues include:~~ costs;

Ÿ• ~~continually~~weakened ~~developing~~financial ~~and~~strength ~~complex~~of ~~environmental~~merchant ~~laws~~generators, ~~regulations~~especially ~~and~~those ~~issues~~with coal-fired energy centers, including ~~air~~their ~~and~~ability ~~water~~to ~~quality~~generate ~~standards,~~positive ~~mercury~~cash ~~emissions~~flows ~~standards,~~in ~~and~~competitive ~~likely~~markets ~~greenhouse~~as ~~gas~~they ~~limitations~~seek ~~and~~to ~~ash~~comply ~~management~~with ~~requirements~~environmental regulations;

Ÿ• ~~political~~the ~~and~~availability ~~regulatory~~of ~~resistance~~fuel toand ~~higher~~increases ~~rates,~~or ~~especially~~decreases in afuel ~~difficult economic environment~~prices;

Ÿ• the ~~potential~~availability ~~for~~of ~~changes~~qualified inlabor ~~laws,~~and ~~regulation~~material, and ~~policies~~rising ~~at the state and federal level, including those resulting from election cycles~~costs;

Ÿ• ~~access~~regulatory ~~to, and uncertainty in, the capital and credit markets~~lag;

Ÿ• the ~~potential~~influence ~~for~~of ~~more~~macroeconomic ~~intense~~factors, ~~competition~~such inas ~~generation,~~yields ~~supply~~on ~~and~~United ~~distribution~~States treasury securities, ~~including~~on ~~new~~allowed ~~technologies~~rates of return on equity provided by regulators;

Ÿ• ~~pressure~~decreased onor ~~customer~~negative ~~growth~~free ~~and~~cash ~~usage~~flows indue ~~light~~to ofrising ~~current~~infrastructure ~~economic~~investments ~~conditions~~ and ~~energy~~regulatory ~~efficiency initiatives~~frameworks;

Ÿ• ~~the~~public ~~potential~~concern ~~for~~about ~~reregulation~~the insiting ~~some~~of ~~states,~~new ~~which could cause electric distribution companies to build or acquire generation~~ facilities ~~and to purchase less power from electric generating companies such as Genco and AERG~~;

Ÿ• ~~changes~~aging ininfrastructure and the ~~structure~~need ofto ~~the~~construct ~~industry~~new aspower ageneration, ~~result~~transmission ofand ~~changes~~distribution infacilities, ~~federal~~which ~~and~~have ~~state~~long ~~laws~~time frames to completion, ~~including~~while at the ~~formation~~same oftime, ~~merchant~~having ~~generators,~~little ~~independent~~long-term ~~transmission~~visibility ~~entities~~on power and ~~RTOs~~commodity prices;

Ÿ• ~~increases,~~legislation ~~decreases~~or ~~and~~proposals ~~volatility~~for inprograms ~~power prices due~~ to ~~the~~encourage ~~balance~~or ofmandate ~~supply~~energy ~~and~~efficiency ~~demand~~ and ~~marginal~~renewable ~~fuel~~sources ~~costs~~of power;

Ÿ• ~~the~~public ~~availability~~concerns ofabout ~~fuel~~nuclear generation and ~~increases~~decommissioning orand ~~decreases~~the indisposal ~~fuel~~of ~~prices~~nuclear waste; and

Ÿ• ~~the~~consolidation ~~availability~~ of ~~qualified~~electric ~~labor~~ and ~~material,~~natural ~~and~~gas ~~rising costs;~~companies.

~~Ÿ regulatory lag;~~14

ŸTable ~~decreased~~of ~~or negative free cash flows due to rising infrastructure investments and regulatory frameworks;~~Contents

ŸWe ~~public~~are ~~concern~~monitoring ~~about~~these ~~the~~issues. ~~siting~~Except as otherwise noted in this report, we are unable to predict what impact, if any, these issues will have on our results of ~~new~~operations, ~~facilities;~~financial position, or liquidity. For additional information, see Risk Factors under Part I, Item 1A, and Outlook in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, and Note 2 – Rate and Regulatory Matters and Note 15 – Commitments and Contingencies under Part II, Item 8, of this report.

~~Ÿ aging infrastructure and the need to construct new power generation, transmission and distribution facilities;~~15

ŸTable ~~legislation or proposals for programs to encourage or mandate energy efficiency and renewable sources~~ of ~~power;~~Contents

ŸOPERATING ~~public concerns about nuclear plant operation and decommissioning and the disposal of nuclear waste; and~~STATISTICS

The following tables present key electric and natural gas operating statistics for Ameren for the past three years:

Ÿ consolidation of electric and natural gas companies.



Electric Operating Statistics – Year Ended December 31,	2012			2011			2010
Electric Sales – kilowatthours (in millions):
Ameren Missouri:
Residential	13,385			13,867			14,640
Commercial	14,575			14,743			15,002
Industrial	8,660			8,691			8,656
Other	126			127			129
Native load subtotal	36,746			37,428			38,427
Off-system and wholesale	7,293			10,715			9,796
Subtotal	44,039			48,143			48,223
Ameren Illinois:
Residential
Power supply and delivery service	9,507			11,771			12,340
Delivery service only	2,103			77			1
Commercial
Power supply and delivery service	2,985			3,662			4,419
Delivery service only	9,175			8,561			8,051
Industrial
Power supply and delivery service	1,595			1,502			1,389
Delivery service only	11,753			11,360			11,147
Other	523			529			545
Native load subtotal	37,641			37,462			37,892
Merchant Generation:
Nonaffiliate energy sales	25,552			31,148			30,788
Affiliate native energy sales	1,679			1,004			949
Subtotal	27,231			32,152			31,737
Eliminate affiliate sales	(1,679		)	(1,004		)	(949		)
Eliminate Ameren Illinois/Merchant Generation common customers	(7,261		)	(5,454		)	(5,016		)
Ameren total	99,971			111,299			111,887
Electric Operating Revenues (in millions):
Ameren Missouri:
Residential	$	1,297		$	1,272		$	1,193
Commercial	1,088			1,084			1,004
Industrial	435			438			399
Other	104			76			91
Native load subtotal	$	2,924		$	2,870		$	2,687
Off-system and wholesale	208			352			343
Subtotal	$	3,132		$	3,222		$	3,030
Ameren Illinois:
Residential
Power supply and delivery service	$	961		$	1,194		$	1,270
Delivery service only	90			3			—
Commercial
Power supply and delivery service	254			350			425
Delivery service only	177			157			143
Industrial
Power supply and delivery service	57			65			66
Delivery service only	46			43			38
Other	154			128			119
Native load subtotal	$	1,739		$	1,940		$	2,061
Merchant Generation:
Nonaffiliate energy sales	$	1,047		$	1,382		$	1,442
Affiliate native energy sales	311			232			231
Other	15			12			20
Subtotal	$	1,373		$	1,626		$	1,693
Eliminate affiliate revenues	(340		)	(258		)	(263		)
Ameren total	$	5,904		$	6,530		$	6,521

14 16

Table of Contents

We are monitoring these issues. Except as otherwise noted in this report, we are unable to predict what impact, if any, these issues will have on our results of operations, financial position, or liquidity. For additional information, see Risk Factors under Part I, Item 1A, and Outlook in



Electric Operating Statistics – Year Ended December 31,	2012			2011			2010
Electric Generation – megawatthours (in millions):
Ameren Missouri	44.7			48.8			48.1
Merchant Generation:
Genco	18.5			22.0			22.0
AERG	7.2			7.0			7.5
Medina Valley	—			0.1			0.1
Subtotal	25.7			29.1			29.6
Ameren total	70.4			77.9			77.7
Price per ton of delivered coal (average)	$	36.63		$	33.79		$	32.91
Source of energy supply:
Coal	65.1		%	66.5		%	65.7		%
Nuclear	12.4			9.4			8.9
Hydroelectric	1.1			1.3			1.6
Natural gas	2.7			1.1			1.0
Purchased – Wind	0.4			0.3			0.3
Purchased – Other	18.3			21.4			22.5
	100.0		%	100.0		%	100.0		%

Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, and Note 2 – Rate and Regulatory Matters and Note 15 – Commitments and Contingencies under Part II, Item 8, of this report.



Gas Operating Statistics – Year Ended December 31,	2012			2011			2010
Natural Gas Sales (millions of dekatherms):
Ameren Missouri:
Residential	6			7			7
Commercial	3			3			4
Industrial	1			1			1
Subtotal	10			11			12
Ameren Illinois:
Residential	49			56			60
Commercial	17			21			23
Industrial	5			5			7
Other	3			—			—
Subtotal	74			82			90
Other:
Industrial	—			—			1
Subtotal	—			—			1
Ameren total	84			93			103
Natural Gas Operating Revenues (in millions)
Ameren Missouri:
Residential	$	85		$	96		$	100
Commercial	36			41			43
Industrial	8			9			10
Other	10			10			13
Subtotal	$	139		$	156		$	166
Ameren Illinois:
Residential	$	547		$	588		$	649
Commercial	172			195			223
Industrial	24			30			44
Other	43			33			37
Subtotal	$	786		$	846		$	953
Other:
Industrial	$	—		$	—		$	4
Eliminate affiliate revenues	(1		)	(1		)	(6		)
Ameren total	$	924		$	1,001		$	1,117
Peak day throughput (thousands of dekatherms):
Ameren Missouri	139			149			167
Ameren Illinois	1,061			1,157			1,227
Total peak day throughput	1,200			1,306			1,394

~~OPERATING STATISTICS~~ 17

~~The~~Table ~~following~~of ~~tables present key electric and natural gas operating statistics for Ameren for the past three years:~~ Contents

Electric Operating Statistics – Year Ended December 31,	2011			2010			2009
Electric Sales – kilowatthours (in millions):
Ameren Missouri:
Residential		13,867			14,640			13,413
Commercial		14,743			15,002			14,510
Industrial		8,691			8,656			7,037
Other		127			129			137
Native load subtotal		37,428			38,427			35,097
Off-system and wholesale		10,715			9,796			13,965
Subtotal		48,143			48,223			49,062
Ameren Illinois:
Residential
Power supply and delivery service		11,771			12,340			11,089
Delivery service only		77			1			-
Commercial
Power supply and delivery service		3,662			4,419			5,235
Delivery service only		8,561			8,051			6,797
Industrial
Power supply and delivery service		1,502			1,389			514
Delivery service only		11,360			11,147			10,712
Other		529			545			546
Native load subtotal		37,462			37,892			34,893
Merchant Generation:
Nonaffiliate energy sales		31,148			30,788			25,673
Affiliate native energy sales		1,004			949			3,529
Subtotal		32,152			31,737			29,202
Eliminate affiliate sales		(1,004	)		(949	)		(3,529	)
Eliminate Ameren Illinois/Merchant Generation common customers		(5,454	)		(5,016	)		(5,566	)
Ameren total		111,299			111,887			104,062
Electric Operating Revenues (in millions):
Ameren Missouri:
Residential	$	1,272		$	1,193		$	982
Commercial		1,084			1,004			881
Industrial		438			399			314
Other		76			91			62
Native load subtotal	$	2,870		$	2,687		$	2,239
Off-system and wholesale		352			343			461
Subtotal	$	3,222		$	3,030		$	2,700
Ameren Illinois:
Residential
Power supply and delivery service	$	1,194		$	1,270		$	1,094
Delivery service only		3			-			-
Commercial
Power supply and delivery service		350			425			521
Delivery service only		157			143			103
Industrial
Power supply and delivery service		65			66			22
Delivery service only		43			38			36
Other		128			119			189
Native load subtotal	$	1,940		$	2,061		$	1,965
Merchant Generation:
Nonaffiliate energy sales	$	1,382		$	1,442		$	1,340
Affiliate native energy sales		235			231			385
Other		12			20			(15	)
Subtotal	$	1,629		$	1,693		$	1,710
Eliminate affiliate revenues		(261	)		(263	)		(435	)
Ameren total	$	6,530		$	6,521		$	5,940

AVAILABLE INFORMATION

The Ameren Companies make available free of charge through Ameren’s website (www.ameren.com) their annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, eXtensible Business Reporting Language (XBRL) documents, and any amendments to those reports filed with or furnished to pursuant to Sections 13(a) or 15(d) of the Exchange Act as soon as reasonably possible after such reports are electronically filed with, or furnished to, the SEC. These documents are also available through an Internet website maintained by the SEC (www.sec.gov). Ameren also uses its website as a channel of distribution of material information relating to the Ameren Companies. Financial and other material information regarding the Ameren Companies is routinely posted and accessible at Ameren’s website.

~~Table~~The Ameren Companies also make available free of ~~Contents~~charge through Ameren’s website the charters of Ameren’s board of directors’ audit and risk committee, human resources committee, nominating and corporate governance committee, finance committee, and nuclear oversight and environmental committee; the corporate governance guidelines; a policy regarding communications to the board of directors; a policy and procedures with respect to related-person transactions; a code of ethics for principal executive and senior financial officers; a code of business conduct applicable to all directors, officers and employees; and a director nomination policy that applies to the Ameren Companies. The information on Ameren’s website, or any other website referenced in this report, is not incorporated by reference into this report.

Electric Operating Statistics – Year Ended December 31,	2011			2010			2009
Electric Generation – megawatthours (in millions):
Ameren Missouri		48.8			48.1			48.7
Merchant Generation:
Genco		22.0			22.0			20.5
AERG		7.0			7.5			6.8
Medina Valley		0.1			0.1			0.2
Subtotal		29.1			29.6			27.5
Ameren total		77.9			77.7			76.2
Price per ton of delivered coal (average)	$	33.79		$	32.91		$	29.85
Source of energy supply:
Coal		66.5	%		65.7	%		67.0	%
Nuclear		9.4			8.9			10.8
Hydroelectric		1.3			1.6			2.0
Gas		1.1			1.0			0.6
Purchased – Wind		0.3			0.3			0.1
Purchased – Other		21.4			22.5			19.5
		100.0	%		100.0	%		100.0	%


ITEM 1A.	RISK FACTORS

Gas Operating Statistics – Year Ended December 31,	2011			2010			2009
Gas Sales (millions of Dth)
Ameren Missouri:
Residential		7			7			7
Commercial		3			4			4
Industrial		1			1			1
Subtotal		11			12			12
Ameren Illinois:
Residential		56			60			60
Commercial		21			23			26
Industrial		5			7			7
Subtotal		82			90			93
Other:
Industrial		-			1			3
Subtotal		-			1			3
Ameren total		93			103			108
Natural Gas Operating Revenues (in millions)
Ameren Missouri:
Residential	$	96		$	100		$	106
Commercial		41			43			47
Industrial		9			10			10
Other		10			13			7
Subtotal	$	156		$	166		$	170
Ameren Illinois:
Residential	$	588		$	649		$	646
Commercial		195			223			259
Industrial		30			44			38
Other		33			37			72
Subtotal	$	846		$	953		$	1,015
Other:
Industrial	$	-		$	4		$	15
Subtotal	$	-		$	4		$	15
Eliminate affiliate revenues		(1	)		(6	)		(5	)
Ameren total	$	1,001		$	1,117		$	1,195
Peak day throughput (thousands of Dth):
Ameren Missouri		149			167			163
Ameren Illinois		1,157			1,227			1,353
Total peak day throughput		1,306			1,394			1,516

Investors should review carefully the following material risk factors and the other information contained in this report. The risks that the Ameren Companies face are not limited to those in this section. There may be further risks and uncertainties that are not presently known or that are not currently believed to be material that may adversely affect the results of operations, financial position, and liquidity of the Ameren Companies. See Forward-Looking Statements above and Outlook in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, of this report.

16The Ameren Companies are subject to extensive regulation of their businesses, which could adversely affect their results of operations, financial position, and liquidity.

~~Table~~The Ameren Companies are subject to, or affected by, extensive federal, state, and local regulation. This extensive regulatory framework, some but not all of ~~Contents~~which is more specifically identified in the following risk factors, regulates, among other matters, the electric and natural gas industries; rate and cost structure of utilities; operation of nuclear energy centers; construction and operation of generation, transmission, and distribution facilities; acquisition, disposal, depreciation and amortization of assets and facilities; transmission reliability; and

~~AVAILABLE~~present ~~INFORMATION~~or prospective wholesale and retail competition. The Ameren Companies must address in their business planning and management of operations the effects of existing and proposed laws and regulations and potential changes in the regulatory framework, including initiatives by federal and state legislatures, RTOs, utility regulators, and taxing authorities. Significant changes in the nature of the regulation of the Ameren Companies’ businesses could require changes to their business planning and management of their businesses and could adversely affect their results of operations, financial position, and liquidity. Failure of the Ameren Companies to obtain adequate rates or regulatory approvals in a timely manner, failure to obtain necessary licenses or permits from regulatory authorities, new or modified laws, regulations, standards, interpretations, or other legal requirements, or increased compliance costs could adversely impact the Ameren Companies’ results of operations, financial position, and liquidity.

The ~~Ameren~~electric ~~Companies~~and ~~make~~natural ~~available~~gas ~~free~~rates ofthat ~~charge through~~ Ameren’s ~~website~~Missouri ~~(www.ameren.com)~~and ~~their~~Ameren ~~annual~~Illinois ~~reports~~are onallowed ~~Form~~to ~~10-K,~~charge ~~quarterly reports~~are ondetermined ~~Form~~through ~~10-Q,~~regulatory ~~current reports on Form 8-K~~proceedings, ~~Ameren’s~~which ~~eXtensible~~are ~~Business~~subject ~~Reporting~~to ~~Language (XBRL) documents~~appeal, and ~~any~~are ~~amendments~~subject to ~~those~~legislative ~~reports~~actions, ~~filed~~which ~~with~~are orlargely ~~furnished~~outside ~~to pursuant to Sections 13(a) or 15(d)~~ of ~~the~~their ~~Exchange~~control. ~~Act~~Any asevents ~~soon as~~that ~~reasonably~~prevent ~~possible~~Ameren ~~after~~Missouri ~~such reports are electronically filed with,~~ or ~~furnished~~Ameren ~~to,~~Illinois ~~the~~from ~~SEC.~~recovering ~~These~~their ~~documents~~respective ~~are~~costs ~~also~~or ~~available~~from ~~through~~earning anappropriate ~~Internet~~returns ~~website~~on ~~maintained~~their byinvestments ~~the~~could ~~SEC~~adversely ~~(www.sec.gov).~~affect ~~Ameren also uses its website as a channel of distribution of material information relating to~~ the Ameren Companies.' ~~Financial~~results ~~and~~of ~~other~~operations, ~~material~~financial ~~information~~position, ~~regarding the Ameren Companies is routinely posted~~ and ~~accessible at Ameren’s website~~liquidity.

The rates that Ameren ~~Companies~~Missouri ~~also~~and ~~make~~Ameren ~~available~~Illinois ~~free~~are ofallowed to charge ~~through~~for ~~Ameren’s~~their ~~website~~utility services significantly influence the ~~charters~~results of ~~Ameren’s~~operations, ~~board~~financial position, and liquidity of ~~directors’~~these ~~audit~~ companies and ~~risk~~Ameren. ~~committee,~~The ~~human~~electric ~~resources~~and ~~committee,~~natural ~~nominating~~gas utility industries are highly regulated. The utility rates charged to Ameren Missouri and ~~corporate~~Ameren ~~governance~~Illinois ~~committee~~customers are determined, ~~finance~~in ~~committee~~large part, ~~nuclear~~by ~~oversight~~governmental ~~and~~entities, ~~environmental~~including ~~committee~~the MoPSC, the ICC, and ~~public~~FERC. ~~policy~~Decisions ~~committee;~~by these entities are influenced by many factors, including the ~~corporate~~cost ~~governance~~of ~~guidelines;~~providing aservice, ~~policy~~the ~~regarding communications~~prudency toof expenditures, the ~~board~~quality of ~~directors;~~service, aregulatory staff knowledge and experience, economic conditions, public policy, and ~~procedures~~social ~~with~~and ~~respect~~political toviews. ~~related-person~~Decisions ~~transactions;~~made aby ~~code~~these governmental entities regarding rates are largely outside of ~~ethics~~Ameren ~~for~~Missouri’s ~~principal~~and ~~executive~~Ameren Illinois’ control. Regulatory lag involved in filing and ~~senior~~getting ~~financial~~new ~~officers;~~rates approved could have a ~~code~~material ofadverse ~~business~~effect ~~conduct~~on ~~applicable~~our toresults ~~all~~of ~~directors~~operations, ~~officers and~~financial ~~employees;~~position, and aliquidity. ~~director~~Rate ~~nomination~~orders ~~policy~~are ~~that~~also ~~applies~~subject to ~~the~~appeal, ~~Ameren~~which ~~Companies.~~creates ~~The~~additional ~~information~~uncertainty onas ~~Ameren’s~~to ~~website,~~the orrates ~~any~~Ameren ~~other~~Missouri ~~website~~and ~~referenced~~Ameren inIllinois ~~this~~will ~~report,~~ultimately isbe ~~not~~allowed ~~incorporated~~to bycharge ~~reference~~for ~~into~~their ~~this report~~services.

~~ITEM~~Ameren 1AMissouri electric and natural gas utility rates and Ameren Illinois natural gas utility rates are typically established in regulatory proceedings that take up to 11 months to complete. ~~RISK~~Rates ~~FACTORS~~established in those proceedings for Ameren Missouri are primarily based on historical costs and revenues. Rates established in those proceedings for Ameren Illinois may be based on historical or estimated future costs and revenues. Thus, the rates a utility is allowed to charge may not match its costs at any given time. Rates include an allowed return on investments by the regulators. Although rate regulation is premised on

Investors should review carefully the following risk factors and the other information contained in this report. The risks that the Ameren Companies face are not limited to those in this section. There may be additional risks and uncertainties (either currently unknown or not currently believed to be material) that could adversely affect the results of operations, financial position, and liquidity of the Ameren Companies. See Forward-Looking Statements above and Outlook in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, of this report. 18

~~The~~Table ~~Ameren Companies are subject to extensive regulation~~ of ~~their businesses, which could adversely affect their results of operations, financial position, and liquidity.~~ Contents

~~The~~providing ~~Ameren~~a ~~Companies~~reasonable ~~are~~opportunity ~~subject~~ to, orearn ~~affected~~a ~~by,~~reasonable ~~extensive~~rate ~~federal,~~of ~~state~~return on invested capital, ~~and~~there ~~local~~can ~~regulation.~~be ~~This~~no ~~extensive~~assurance ~~regulatory~~that ~~framework,~~the ~~some~~applicable ~~but~~regulatory ~~not~~commission will judge all the costs of ~~which~~Ameren isMissouri ~~more~~and ~~specifically~~Ameren ~~identified~~Illinois into have been prudently incurred or that the ~~following risk~~regulatory ~~factors,~~process ~~regulates,~~in ~~among~~which ~~other~~rates ~~matters,~~are ~~the~~determined ~~electric~~will ~~and~~always ~~natural~~result ~~gas~~in ~~industries;~~rates ~~rate~~that ~~and~~will ~~cost~~produce ~~structure~~full recovery of ~~utilities;~~such ~~operation~~costs of or an adequate return on those investments.

~~nuclear~~In ~~power~~years ~~facilities;~~when ~~construction~~capital investments and ~~operation~~operations ofcosts ~~generation,~~rise ~~transmission~~while ~~and~~customer ~~distribution~~usage ~~facilities; acquisition~~declines, ~~disposal,~~such ~~depreciation~~as ~~and~~in ~~amortization~~2012, ofAmeren ~~assets~~Missouri and ~~facilities; transmission reliability; and present or prospective wholesale and retail competition. The~~ Ameren ~~Companies~~Illinois ~~must~~may ~~address~~not inbe ~~their~~able ~~business~~to ~~planning~~earn ~~and management of operations~~ the ~~effects~~allowed ofreturn ~~existing~~established ~~and~~by ~~proposed~~their ~~laws~~regulators. ~~and~~This ~~regulations~~could ~~and~~result ~~potential changes~~ in the ~~regulatory~~deferral ~~framework,~~or ~~including~~elimination ~~initiatives~~of byplanned ~~federal~~capital ~~and state legislatures~~investments, ~~RTOs,~~which ~~utility~~reduces ~~regulators, and taxing authorities. Significant changes in~~ the ~~nature~~rate ofbase ~~the~~investments ~~regulation of~~ the ~~Ameren~~utility ~~Companies’~~operations ~~businesses~~earn ~~could require~~a ~~changes~~rate ~~to their business planning and management~~ of ~~their~~return ~~businesses~~on. ~~and could adversely affect their results of operations~~Additionally, ~~financial~~a ~~position,~~period ~~and liquidity. Failure~~ of ~~the~~increasing ~~Ameren~~rates ~~Companies~~for toour ~~obtain~~customers ~~adequate~~could ~~rates~~result ~~or regulatory approvals~~ in aadditional ~~timely manner, failure to obtain necessary licenses or permits from~~ regulatory ~~authorities,~~and ~~new~~legislative ~~or changed laws~~actions, ~~regulations,~~as ~~standards,~~well ~~interpretations,~~as orcompetitive ~~other~~and ~~legal~~political ~~requirements~~pressures, orwhich ~~increased compliance costs~~ could adversely ~~impact~~affect the Ameren Companies’' results of operations, financial position, and liquidity.

~~The~~Through ~~electric~~its ~~and~~participation ~~natural~~in ~~gas~~the ~~rates~~performance-based ~~that~~formula ~~Ameren Missouri~~ratemaking ~~and~~process established pursuant to the IEIMA, Ameren Illinois’ ~~are~~return ~~allowed~~on equity will be directly correlated to ~~charge~~yields ~~are~~on ~~determined~~United ~~through~~States ~~regulatory~~treasury ~~proceedings~~bonds. Additionally, ~~which~~Ameren ~~are~~Illinois will be subject to ~~appeal,~~an ~~and~~annual ~~are~~ICC ~~subject~~prudence review and to ~~legislative~~the ~~actions,~~ICC's ~~which~~implementation ~~are~~of ~~largely~~the ~~outside~~IEIMA, ofand ~~their~~Ameren ~~control.~~Illinois ~~Any~~will ~~events~~be ~~that~~required ~~prevent~~to ~~Ameren Missouri~~achieve orperformance ~~Ameren~~objectives, ~~Illinois~~increase ~~from~~capital ~~recovering~~spending ~~their~~levels, ~~respective~~and ~~costs~~meet orjob ~~from~~creation ~~earning~~targets, ~~appropriate~~which ~~returns~~if onnot ~~their~~successfully ~~investments~~completed ~~could~~or ~~have~~achieved acould ~~material~~adversely ~~adverse~~affect ~~effect~~Ameren onIllinois' results of operations, financial position, and liquidity.

~~The~~In ~~rates~~2012, ~~that~~ Ameren ~~Missouri~~Illinois ~~and~~elected ~~Ameren~~to ~~Illinois~~participate ~~are~~in ~~allowed~~the toperformance-based ~~charge~~formula ~~for~~ratemaking ~~their~~process ~~utility~~established ~~services~~pursuant ~~significantly~~to ~~influence~~ the ~~results~~IEIMA ~~of operations,~~for ~~financial~~its ~~position,~~electric ~~and~~distribution ~~liquidity~~business. ofThe ~~these~~ICC ~~companies~~will ~~and~~annually review Ameren. ~~The~~Illinois’ ~~electric~~performance-based ~~and~~rate ~~natural~~filings ~~gas~~under ~~utility~~the ~~industries~~IEIMA ~~are~~for ~~highly~~reasonableness ~~regulated~~and prudency. ~~The~~If ~~utility~~the ~~rates~~ICC ~~charged~~were to ~~Ameren~~conclude ~~Missouri~~that ~~and~~ Ameren Illinois’ ~~customers~~incurred ~~are~~costs ~~determined,~~were innot ~~large part,~~prudently ~~by governmental entities~~incurred, ~~including~~ the ~~MoPSC, the~~ ICC, ~~and~~could ~~FERC.~~disallow ~~Decisions~~recovery byof ~~these~~such ~~entities~~costs. ~~are~~Ameren ~~influenced~~is byalso ~~many~~subject ~~factors,~~to ~~including~~ the ~~cost~~ICC's implementation of ~~providing~~the ~~service,~~IEIMA's ~~the~~formula ~~prudency~~rates. ofAfter ~~expenditures,~~reviewing the ~~quality~~ICC's ofIEIMA ~~service,~~formula ~~regulatory~~rate ~~staff knowledge~~orders ~~and~~in ~~experience~~2012, ~~economic~~Ameren ~~conditions,~~Illinois ~~public~~believes ~~policy,~~that ~~and~~the ~~social~~ICC ~~and~~has ~~political~~incorrectly ~~views.~~implemented ~~Decisions~~the ~~made~~IEIMA. byAmeren ~~these~~Illinois ~~governmental~~objects ~~entities~~to ~~regarding~~the ~~rates~~ICC's ~~are~~use ~~largely outside~~ of ~~Ameren~~an ~~Missouri’s~~average ~~and~~rate ~~Ameren~~base ~~Illinois’~~as ~~control.~~opposed ~~Regulatory lag~~to ~~involved~~a inyear-end ~~filing~~rate ~~and~~base ~~getting~~in ~~new~~setting rates, ~~approved~~to ~~could~~its ~~have~~treatment aof ~~material~~accumulated ~~adverse~~deferred ~~effect~~income ~~on our results of operations~~taxes, ~~financial position,~~ and ~~liquidity.~~to ~~Rate~~the ~~orders~~methods ~~are~~it ~~also~~used ~~subject~~ to ~~appeal,~~calculate ~~which~~the ~~creates~~equity ~~additional~~portion ~~uncertainty~~of asAmeren toIllinois' ~~the~~capital ~~rates Ameren~~structure ~~Missouri~~ and ~~Ameren~~to ~~Illinois~~calculate ~~will~~interest ~~ultimately~~on bethe ~~allowed~~revenue torequirement ~~charge~~reconciliation ~~for~~and ~~their~~return ~~services~~on equity collar.

~~Ameren~~The ~~Missouri~~return ~~electric~~on ~~and~~equity ~~natural~~component ~~gas utility~~of ~~rates~~the ~~and~~formula rate is equal to the average for the calendar year of the monthly yields of 30-year United States treasury bonds plus 580 basis points for years after 2012. Therefore, Ameren Illinois’ ~~natural~~annual ~~gas~~return ~~utility~~on ~~rates~~equity ~~are~~will ~~typically~~be ~~established~~directly incorrelated ~~regulatory~~to ~~proceedings~~yields ~~that~~on ~~take~~United upStates totreasury 11bonds, ~~months~~which toare ~~complete.~~outside ~~Rates~~of ~~established~~Ameren inIllinois’ ~~those~~ control.

17Ameren Illinois will also be subject to performance

~~Table~~standards. ofFailure ~~Contents~~to achieve the standards will result in a reduction in the company’s allowed return on equity calculated under the formula. The IEIMA provides for return on equity penalties totaling 30 basis points in 2013 through 2015, 34 basis points in 2016 through 2018, and 38 basis points in 2019 through 2022 if the performance standards are not met.

~~proceedings~~Between ~~for~~2012 ~~Ameren Missouri are primarily based on historical costs~~ and ~~revenues.~~2021, ~~Rates established in those proceedings for~~ Ameren Illinois ~~may~~will be ~~based~~required ~~on historical or estimated future costs and revenues. Thus, the rates a utility is allowed~~ to ~~charge~~invest ~~may~~$625 ~~not~~million ~~match~~in ~~its~~capital ~~costs~~expenditures atincremental ~~any given time. Rates include an allowed return on investments by the regulators. Although rate regulation is premised on providing a reasonable opportunity~~ to ~~earn~~Ameren aIllinois’ ~~reasonable~~average ~~rate~~electric ofdelivery ~~return on invested~~ capital, ~~there~~expenditures ~~can~~for becalendar noyears ~~assurance~~2008 ~~that~~through ~~the~~2010 ~~applicable~~to ~~regulatory~~modernize ~~commission~~its ~~will~~distribution ~~judge~~system. ~~all the costs of~~ Ameren ~~Missouri~~Illinois ~~and~~is ~~Ameren~~subject ~~Illinois~~ to ~~have~~monetary ~~been~~penalties ~~prudently~~if ~~incurred~~450 oradditional ~~that~~jobs ~~the regulatory process~~ in ~~which~~Illinois ~~rates~~ are ~~determined~~not ~~will~~created ~~always~~during ~~result in rates that will produce full recovery of such costs or an adequate return on those investments. In 2011, for example,~~ the ~~MoPSC~~peak ~~issued~~program ~~an electric rate order that disallowed $89 million of costs incurred related to the rebuilding of the Taum Sauk energy center~~year. ~~As a result, Ameren and Ameren Missouri each recorded a 2011 pretax charge to earnings of $89 million.~~

~~During~~The ~~periods~~formula ofratemaking ~~rising~~process ~~costs~~would ~~and~~terminate ~~investments~~if orthe ~~declining~~average ~~retail~~residential ~~usage~~rate increases by more than 2.5% annually from June 2011 through May 2014. The average residential rate includes generation service, ~~Ameren~~which ~~Missouri~~is ~~and~~outside of Ameren Illinois’ ~~may~~control, ~~not~~as beAmeren ~~able~~Illinois is required to ~~earn~~purchase ~~the~~all ~~allowed return~~of ~~established~~its power through procurement processes administered by ~~their~~the ~~regulators~~IPA. ~~This~~If ~~could~~the ~~result~~performance-based informula ~~deferral~~rate orprocess ~~elimination~~is ofterminated, ~~planned~~Ameren ~~capital~~Illinois ~~investments.~~would Abe ~~period~~required ofto ~~increasing~~establish future rates ~~for~~through ~~our~~a ~~customers~~traditional ~~could~~rate ~~result~~proceeding inwith ~~additional~~the ~~regulatory~~ICC, ~~and~~which ~~legislative~~might ~~actions,~~not asresult ~~well~~in asrates ~~competitive and~~that ~~political~~produce ~~pressures,~~a ~~which~~full ~~could~~or ~~have~~timely arecovery ~~material~~of ~~adverse~~costs ~~effect~~or onan ~~our~~adequate ~~results~~return ofon ~~operations,~~investments. ~~financial~~Unless ~~position~~extended, ~~and~~the ~~liquidity.~~IEIMA formula ratemaking process expires in 2017.

ByEnergy ~~choosing to participate in the performance-based formula ratemaking process established pursuant to the IEIMA~~conservation, ~~Ameren~~energy ~~Illinois’~~efficiency ~~return on~~efforts ~~equity will be directly correlated to yields on United States treasury bonds. Additionally, Ameren Illinois will be subject to an annual ICC prudence review~~ and ~~will~~other befactors ~~required~~that toreduce ~~achieve~~energy ~~performance~~demand ~~objectives, increase capital spending levels, and meet job creation targets, which if not successfully completed or achieved~~ could ~~have~~adversely aaffect ~~material~~the ~~adverse~~Ameren ~~effect~~Companies’ ~~on its~~ results of operations, financial position, and liquidity.

OnRegulatory ~~January 3,~~and ~~2012,~~legislative ~~Ameren~~bodies ~~Illinois~~have ~~elected~~proposed toor ~~participate~~introduced inrequirements ~~the~~and ~~performance-based~~incentives ~~formula ratemaking process established pursuant~~ to ~~the IEIMA~~reduce byenergy ~~submitting~~consumption. ~~its~~Conservation ~~initial~~and ~~filing~~energy ~~with~~efficiency ~~the~~programs ~~ICC~~are ~~for~~designed ~~its~~to ~~electric~~reduce ~~distribution~~energy ~~business~~demand. ~~The~~Unless ~~ICC~~there ~~will~~is ~~annually~~a ~~review~~regulatory ~~Ameren~~solution ~~Illinois’~~ensuring ~~performance-based~~recovery, ~~rate~~declining ~~filings~~usage ~~under~~will ~~the~~result ~~IEIMA~~in ~~for~~an ~~reasonableness~~underrecovery ~~and~~of ~~prudency.~~fixed ~~The ICC could conclude that Ameren Illinois’ incurred~~ costs ~~were~~at ~~not~~our ~~prudently~~rate-regulated ~~incurred~~business. ~~and~~Ameren ~~thus~~Missouri, ~~disallow~~even ~~recovery~~with ~~of such costs annually. Additionally,~~ the ~~equity~~implementation ~~component~~ of ~~the~~energy ~~formula~~efficiency ~~rate~~programs ~~will~~under ~~be equal to~~ the ~~average~~MEEIA, ~~for~~is ~~the~~exposed ~~applicable~~to ~~calendar~~declining ~~year~~usage oflosses ~~the monthly~~from ~~average~~energy ~~yields~~efficiency ofefforts ~~30-year~~not ~~United~~related ~~States~~to ~~treasury~~its ~~bonds~~specific ~~plus~~programs ~~590~~as ~~basis~~well ~~points~~as ~~for~~distributed ~~2012~~generation ~~and~~sources ~~580~~such ~~basis~~as ~~points~~solar ~~thereafter~~panels. ~~Therefore,~~Macroeconomic ~~Ameren~~factors ~~Illinois’~~resulting ~~annual~~in ~~return~~low oneconomic ~~equity~~growth ~~will~~or becontraction ~~directly~~within ~~correlated~~the toAmeren ~~yields~~Companies' onservice ~~United~~territories ~~States~~could ~~treasury bonds,~~also ~~which~~reduce ~~are~~energy ~~outside of Ameren Illinois’ control~~demand.

~~Ameren~~We ~~Illinois~~are ~~will~~subject ~~also~~to bevarious ~~subject~~environmental tolaws ~~performance~~and ~~standards~~regulations that require significant capital expenditures. Failure to ~~achieve~~ ~~the~~meet these standards ~~will~~could result in a closure of facilities, increase our operating costs, adversely affect our results of operations, financial position, and liquidity, or expose us to fines and liabilities.

~~reduction~~We inare ~~the~~subject ~~company’s~~to ~~allowed~~various ~~return~~environmental onlaws ~~equity~~and ~~calculated~~regulations ~~under~~enforced ~~the~~by ~~formula~~federal, state, and local authorities. ~~The~~From ~~IEIMA~~the ~~provides~~beginning ~~for~~phases ~~return~~of onsiting ~~equity~~and ~~penalties~~development ~~totaling~~to 30the ~~basis~~operation ~~points~~of inexisting ~~2013~~or ~~through~~new ~~2015~~electric generating, 34transmission ~~basis points~~and indistribution ~~2016~~facilities ~~through~~and ~~2018~~natural gas storage, transmission and 38distribution ~~basis~~facilities, ~~points~~our inactivities ~~2019~~involve ~~through~~compliance ~~2022~~with ifdiverse ~~the~~environmental ~~performance~~laws ~~standards~~and ~~are~~regulations. ~~not~~These ~~met.~~laws and

Between 2012 and 2021, Ameren Illinois will be required to invest $625 million in capital expenditures incremental to Ameren Illinois’ average electric delivery capital expenditures for calendar years 2008 through 2010 to modernize its distribution system. Ameren Illinois is subject to monetary penalties if 450 additional jobs in Illinois are not created during the peak program year. 19

~~The~~Table formula ratemaking process would terminate if the average residential rate increases by more than 2.5% annually from June 2011 through May 2014. The average residential rate includes generation service, which is outside of Ameren Illinois’ control, as Ameren Illinois is required to purchase all of its power through procurement processes administered by the IPA. If the performance-based formula rate process is terminated, Ameren Illinois would be required to establish future rates using a traditional rate proceeding with the ICC, which may not result in rates that produce a full or timely recovery of costs or an adequate return on investments. Unless extended, the IEIMA formula ratemaking process expires in 2017. Contents

~~Energy~~regulations ~~conservation~~address emissions, impacts to air, land, and ~~energy~~water, ~~efficiency~~noise, ~~efforts~~protected ~~could~~natural ~~have~~and acultural ~~material~~resources ~~adverse~~(such ~~effect~~as onwetlands, ~~the~~endangered ~~Ameren~~species, ~~Companies’~~and ~~results~~other ofprotected ~~operations~~wildlife, ~~financial~~ ~~position~~and archaeological and historical resources), and ~~liquidity~~chemical and waste handling. Complex and lengthy processes are required to obtain approvals, permits, or licenses for new, existing, or modified facilities. Additionally, the use and handling of various chemicals or hazardous materials (including wastes) requires release prevention plans and emergency response procedures.

~~Regulatory~~We ~~and~~are ~~legislative~~also ~~bodies~~subject ~~have~~to ~~proposed~~liability orunder ~~introduced~~environmental ~~requirements~~laws ~~and~~that ~~incentives~~address ~~to reduce~~the ~~energy~~remediation ~~consumption.~~of ~~Conservation~~environmental ~~and~~contamination ~~energy~~of ~~efficiency~~property ~~programs~~now ~~are~~or ~~designed~~formerly toowned ~~reduce~~by ~~energy~~us ~~demand.~~or ~~Unless~~by ~~there~~our ispredecessors, aas ~~regulatory~~well ~~solution,~~as ~~declining~~property ~~usage~~contaminated ~~will~~by ~~result~~hazardous insubstances anthat ~~underrecovery~~we ofgenerated. ~~fixed~~Such ~~costs~~sites atinclude ~~our~~MGP ~~rate~~sites and third-~~regulated~~party ~~business~~sites, such as landfills. ~~A reduction~~Additionally, inprivate ~~energy~~individuals ~~demand~~may ~~could~~seek ~~have~~to aenforce ~~material~~environmental ~~adverse~~laws ~~effect~~and onregulations ~~the~~against ~~Ameren~~us ~~Companies’~~and ~~results~~could ofallege ~~operations,~~injury ~~financial~~from ~~position,~~exposure ~~and~~to ~~liquidity.~~hazardous materials.

WeIn ~~are~~addition ~~subject~~ to ~~various~~existing ~~environmental~~ laws and regulations, including the Illinois MPS that ~~require~~applies to our energy centers in Illinois, the EPA is developing numerous new environmental regulations that will have a significant ~~capital~~impact ~~expenditures~~on orthe electric utility industry. These regulations could ~~result~~be inparticularly ~~closure~~burdensome offor ~~facilities~~certain companies, ~~could~~including ~~increase~~Ameren, ~~our~~Ameren ~~operating costs~~Missouri, and ~~could~~AER, ~~materially adversely~~that ~~influence~~operate orcoal-fired ~~limit~~energy ~~our~~centers. ~~results~~These ofnew ~~operations,~~regulations ~~financial~~may ~~position~~be litigated, ~~and~~so ~~liquidity~~the timing of their ultimate implementation is uncertain, oras ~~expose~~evidenced usby tothe ~~fines~~stay and ~~liabilities.~~remand of the CSAPR.

WeAmeren ~~are~~is also subject to ~~various~~risks ~~environmental~~in connection with changing or conflicting interpretations of existing laws and regulations. ~~enforced~~The byEPA ~~federal,~~is ~~state~~engaged in an enforcement initiative to determine whether coal-fired energy centers failed to comply with the requirements of the NSR and ~~local~~NSPS ~~authorities~~provisions under the Clean Air Act when the energy centers implemented modifications. ~~From~~Following the ~~beginning~~issuance ~~phases~~of a Notice of ~~siting and~~Violation, ~~development~~in toJanuary 2011, the ~~ongoing~~Department ~~operation~~of Justice on behalf of ~~existing~~the orEPA ~~new~~filed ~~electric~~a ~~generating,~~complaint ~~transmission~~against ~~and~~Ameren ~~distribution~~Missouri ~~facilities~~in ~~and~~the ~~natural~~United ~~gas~~States ~~storage,~~District ~~transmission~~Court ~~and~~for ~~distribution~~the ~~facilities~~Eastern District of Missouri. The EPA’s complaint alleges that in performing projects at its Rush Island coal-fired energy center, ~~our~~Ameren ~~activities~~Missouri ~~involve~~violated ~~compliance~~provisions ~~with~~of ~~diverse~~the ~~environmental laws~~Clean Air Act and ~~regulations~~Missouri law. ~~These~~In ~~laws~~January ~~and~~2012, ~~regulations~~the ~~address~~United ~~emissions~~States District Court granted, ~~impacts~~in part, Ameren Missouri’s motion to ~~air,~~dismiss ~~land~~various ~~and~~aspects ~~water~~of the EPA’s penalty claims. The EPA’s claims for injunctive relief, ~~noise~~including requiring the installation of pollution control equipment, ~~protected~~remain. ~~natural~~Litigation of this matter could take many years. An outcome in this matter adverse to Ameren Missouri could require substantial capital expenditures and ~~cultural~~the ~~resources~~payment ~~(such~~of assubstantial ~~wetlands~~penalties, neither of which can be determined at this time. Such expenditures could affect unit retirement and replacement decisions.

18In August 2012, Genco received a Notice of Violation from the EPA alleging violations of permitting requirements including Title V of the Clean Air Act. The EPA contends that projects performed in 1997, 2006, and 2007 at Genco's Newton energy center violated federal laws. Ameren and Genco are unable to predict the outcome of this matter and whether the EPA will address this Notice of Violation administratively or through

~~Table of Contents~~litigation.

~~endangered~~Ameren, ~~species~~Ameren Missouri, and ~~other~~AER ~~protected~~have ~~wildlife,~~incurred and ~~archeological~~expect ~~and~~to ~~historical~~incur ~~resources),~~significant ~~and~~costs ~~chemical~~related to environmental compliance and ~~waste~~site ~~handling~~remediation. ~~Complex~~New environmental regulations, revised environmental regulations, voluntary compliance guidelines, enforcement initiatives, or legislation could result in a significant increase in capital expenditures and ~~lengthy~~operating ~~processes~~costs, ~~are~~decreased ~~required~~revenues, toincreased ~~obtain~~financing ~~approvals~~requirements, ~~permits~~ penalties, fines, or ~~licenses~~closure of facilities for ~~new~~Ameren, ~~existing~~Ameren Missouri, orand ~~modified~~AER. Actions required to ensure that our facilities and operations are in compliance with environmental laws and regulations could be prohibitively expensive. ~~Additionally~~As a result, environmental regulations could require us to close or to significantly alter the ~~use~~operation ~~and~~of ~~handling~~our energy centers, which could have an adverse effect on our results of ~~various~~operations, ~~chemicals~~financial orposition, ~~hazardous~~and ~~materials~~liquidity, (including ~~wastes)~~the ~~requires~~impairment ~~release~~of ~~prevention~~plant ~~plans~~assets. Although costs incurred by Ameren Missouri ensure that its facilities are in compliance with environmental laws and ~~emergency~~regulations ~~response~~would ~~procedures~~be eligible for recovery in rates over time, subject to MoPSC approval in a rate proceeding, there is no similar cost recovery mechanism with respect to AER. We are unable to predict the ultimate impact of these matters on our results of operations, financial position, and liquidity.

WeFuture ~~are~~limits ~~also~~on ~~subject~~greenhouse togas ~~liability~~emissions ~~under~~would ~~environmental~~probably ~~laws~~require ~~for~~Ameren, ~~remediating~~Ameren ~~environmental~~Missouri, ~~contamination~~and ofAER ~~property~~to ~~now~~incur orsignificant ~~formerly~~increases ~~owned~~in bycapital usexpenditures ~~or by~~and ~~our~~operating ~~predecessors~~costs, aswhich, ~~well~~if asexcessive, ~~property~~could ~~contaminated~~result byin ~~hazardous~~the ~~substances~~closures ~~that~~of ~~we generated. Such sites include MGP sites and third~~coal-~~party~~fired ~~sites~~energy centers, ~~such~~impairment asof ~~landfills. Additionally~~assets, ~~private~~or ~~individuals~~otherwise ~~may~~adversely ~~seek~~affect toour ~~enforce~~results ~~environmental~~of ~~laws~~operations, ~~and regulations~~financial ~~against~~position, us and ~~could allege injury from exposure to hazardous materials~~liquidity.

InState ~~addition~~and federal authorities, including the United States Congress, have considered initiatives to ~~existing~~limit ~~laws~~greenhouse gas emissions and ~~regulations~~to address global climate change. Impacts from any climate change legislation or regulation could vary, ~~including~~ depending upon proposed CO2 emission limits, the ~~Illinois~~timing ~~MPS~~of ~~that~~implementation ~~applies~~of tothose ~~our~~limits, ~~energy~~the ~~centers~~method inof ~~Illinois~~distributing any allowances, the ~~EPA~~degree isto ~~developing~~which ~~numerous~~offsets ~~new~~are ~~environmental~~allowed ~~regulations~~and ~~that~~available, ~~will~~and ~~have~~provisions for cost-containment measures, such as a ~~significant~~“safety ~~impact~~valve” onprovision ~~the~~that ~~electric~~provides ~~utility~~a ~~industry~~maximum price for emission allowances. ~~These~~As ~~regulations~~a ~~could~~result beof ~~particularly burdensome~~our ~~for~~diverse ~~certain~~fuel ~~companies~~portfolio, ~~including~~our ~~Ameren,~~emissions ~~Ameren~~of ~~Missouri~~greenhouse ~~and~~gases ~~Genco,~~vary ~~that~~among ~~operate~~our energy centers, but coal-fired ~~plants~~energy centers are significant sources of CO2. ~~These~~The ~~new~~enactment ~~regulations~~of ~~may~~a beclimate ~~litigated,~~change solaw ~~the~~could ~~timing~~result ofin ~~their~~a ~~ultimate~~significant ~~implementation~~rise isin ~~uncertain~~rates for electricity, asand ~~evidenced~~thereby byhousehold ~~the~~costs. ~~stay~~The ofburden ~~the~~could ~~CSAPR by~~fall ~~the~~particularly ~~United~~hard ~~States~~on ~~Court~~electricity ofconsumers ~~Appeals~~and ~~for~~upon the ~~District~~economy in the Midwest because of ~~Columbia~~the region’s reliance on ~~December 30,~~electricity ~~2011.~~generated by coal-fired energy centers.

~~Ameren~~Future ~~also~~federal ~~may~~and bestate ~~subject~~legislation ~~to risks in connection with changing~~ or ~~conflicting interpretations of existing laws and~~ regulations. ~~The~~that ~~EPA~~mandate islimits ~~engaged~~on ~~in an enforcement initiative to determine whether coal-fired power plants failed to comply with~~ the ~~requirements~~emission of ~~the~~greenhouse ~~NSR~~gases ~~and~~would ~~NSPS provisions~~probably ~~under~~result ~~the Clean Air Act when the plants implemented modifications. Following the issuance of a Notice of Violation,~~ in ~~January~~significant ~~2011,~~increases ~~the Department of Justice on behalf of the EPA filed a complaint against Ameren Missouri~~ in ~~the~~capital ~~United States~~expenditures District Court for the Eastern District of Missouri. The EPA’s complaint alleges that in performing projects at its Rush Island coal-fired energy center, Ameren Missouri violated provisions of the Clean Air Act and ~~Missouri~~operating ~~law. In January 2012~~costs, ~~the United States District Court granted~~which, in ~~part~~turn, ~~Ameren~~could ~~Missouri’s~~lead ~~motion~~ to ~~dismiss~~increased ~~various~~liquidity ~~aspects~~needs ofand ~~the~~higher ~~EPA’s~~financing ~~penalty claims~~costs. ~~The EPA’s claims for injunctive relief~~Moreover, ~~including~~if toAmeren ~~require~~Missouri ~~the~~requests ~~installation~~recovery of ~~pollution~~ ~~control~~these ~~equipment,~~costs ~~remain.~~through ~~At present~~rates, ~~the~~its ~~complaint~~regulators ~~does~~could ~~not~~deny ~~include~~some ~~Ameren~~or ~~Missouri’s~~all ~~other coal-fired energy centers, but the EPA has issued Notices~~ of ~~Violation~~these ~~under its NSR enforcement initiative against the company’s Labadie~~costs, ~~Meramec,~~or ~~and~~defer ~~Sioux~~timely ~~coal-fired~~recovery ~~energy centers. Litigation~~ of ~~this matter could take many years to resolve~~them. AnExcessive ~~outcome~~costs ~~in this matter adverse~~ to ~~Ameren~~comply ~~Missouri~~with ~~could~~future require substantial capital expenditures and the payment of substantial penalties, neither of which can be determined at this time. Such expenditures could affect unit retirement and replacement decisions.

Ameren, Ameren Missouri and Genco have incurred and expect to incur significant costs related to environmental compliance and site remediation. New environmental regulations, future environmental regulations, voluntary compliance guidelines, enforcement initiatives, or legislation could result in a significant increase in capital expenditures and operating costs, decreased revenues, increased financing requirements, penalties, fines, or closure of facilities for Ameren, Ameren Missouri and Genco. Actions required to ensure that our facilities and operations are in compliance with environmental laws and regulations could be prohibitively expensive. As a result, environmental regulations could require us to close or to significantly alter the operation of our energy centers, which could have an adverse effect on our results of operations, financial position, and liquidity, including the impairment of plant assets. Although costs incurred by Ameren Missouri to ensure its facilities are in compliance with environmental laws and regulations would be eligible for recovery in rates over time, subject to MoPSC approval in a rate proceeding, there is no similar cost recovery mechanism for Genco or for Ameren’s Merchant Generation business segment. We are unable to predict the ultimate impact of these matters on our results of operations, financial position, and liquidity. 20

~~Future~~Table limits on greenhouse gas emissions would likely require Ameren, Ameren Missouri and Genco to incur significant increases in capital expenditures and operating costs, which, if excessive, could result in the closures of ~~coal-fired energy centers, impairment of assets, or otherwise materially adversely affect our results of operations, financial position, and liquidity.~~ Contents

State and federal authorities, including the United States Congress, have considered initiatives to limit greenhouse gas emissions and to address global climate change. Potential impacts from any climate change legislation or ~~regulation~~regulations ~~could~~might ~~vary,~~force ~~depending upon proposed CO2 emission limits~~Ameren, ~~the~~Ameren ~~timing of implementation of those limits~~Missouri, ~~the~~and ~~method~~AER ~~of distributing any allowances, the degree~~ to ~~which~~close ~~offsets~~some ~~are~~coal-fired ~~allowed~~energy ~~and~~centers ~~available,~~earlier ~~and~~than ~~provisions for cost-containment measures~~planned, ~~such~~which ascould alead ~~“safety~~to ~~valve”~~possible ~~provision~~impairment ~~that~~of ~~provides~~assets aand ~~maximum~~reduced ~~price for emission allowances~~revenues. As a result ~~of our diverse fuel portfolio~~, ~~our~~mandatory ~~emissions~~limits ~~of greenhouse gases vary among our energy centers, but coal-fired power plants are significant sources of CO2. The enactment of a climate change law~~ could ~~result~~have in a ~~significant~~material ~~rise~~adverse ~~in household~~impact ~~costs and rates for electricity could rise significantly. The burden could fall particularly hard~~ on ~~electricity~~Ameren’s, ~~consumers~~Ameren Missouri’s, and ~~upon~~AER's ~~the~~results ~~economy in the Midwest because~~ of ~~the~~operations, ~~region’s~~financial ~~reliance~~position, onand ~~electricity generated by coal-fired power plants~~liquidity.

~~Future~~The ~~federal~~construction of, and ~~state~~capital ~~legislation~~improvements orto, ~~regulations~~the ~~that~~Ameren ~~mandate~~Companies' ~~limits~~electric onand ~~the~~natural ~~emission~~gas ofutility ~~greenhouse~~infrastructure ~~gases~~and ~~would~~AER's ~~likely result~~energy incenters ~~significant~~involve ~~increases~~substantial inrisks. ~~capital~~These ~~expenditures~~risks ~~and~~include ~~operating~~escalating costs, ~~which,~~unsatisfactory inperformance ~~turn~~by the projects when completed, ~~could~~the ~~lead~~inability to ~~increased~~complete ~~liquidity~~projects ~~needs~~as ~~and~~scheduled, ~~higher~~cost ~~financing~~disallowances ~~costs.~~by ~~Moreover~~regulators, toand the ~~extent~~inability ~~Ameren~~to ~~Missouri~~earn ~~requests~~a ~~recovery~~reasonable return on invested capital, any of ~~these~~which could result in higher costs and the closure of facilities.

19The Ameren Companies expect to incur significant capital expenditures to comply with existing and known environmental regulations and to make investments in their electric and natural gas utility infrastructure and in AER's energy centers if they are owned by Ameren over the next five years. Ameren estimates it will incur up to $9.5 billion (Ameren Missouri - up to $3.8 billion; Ameren Illinois - up to $3.9 billion; AER - up to $0.4 billion; other - up to $1.4 billion) of capital expenditures during the period 2013 through 2017. These expenses include construction expenditures, capitalized interest or allowance for funds used during construction, and capital expenditures for compliance with environmental standards and with the requirements of the IEIMA.

~~Table~~Investments in Ameren’s rate-regulated operations are expected to be recoverable from ratepayers, but are subject to prudency reviews and regulatory lag. The recoverability of ~~Contents~~amounts expended in Ameren's Merchant Generation operations will depend upon market prices for capacity and energy.

~~through~~The ~~rates~~ability of the Ameren Companies to complete construction projects successfully, ~~its~~and ~~regulators~~within ~~might~~projected ~~deny~~estimates, ~~some~~is orcontingent ~~all~~upon many variables and subject to substantial risks. These variables include, but are not limited to, project management expertise and escalating costs for materials, labor, and environmental compliance. Delays in obtaining permits, shortages in materials and qualified labor, suppliers and contractors who do not perform as required under their contracts, changes in the scope and timing of projects, the inability to raise capital on favorable terms, or ~~defer~~other ~~timely~~events ~~recovery~~beyond ofour control that could occur may materially affect the schedule, cost, and performance of these ~~costs~~projects. ~~Excessive~~With respect to capital expenditures for pollution control equipment, there is a risk that energy centers will not be permitted to continue to operate if pollution control equipment is not installed by prescribed deadlines or does not perform as expected. Should any such pollution control equipment not be installed on time or perform as expected, the Ameren Companies could be subject to additional costs and to ~~comply~~the ~~with~~loss ~~future~~of ~~legislation~~their investment in the project or ~~regulations~~facility. All ~~might~~of ~~force~~these risks may adversely affect the Ameren Companies’ results of operations, financial position, and liquidity.

~~Ameren~~As of December 31, 2012, Ameren Missouri ~~and~~had ~~Genco~~capitalized to$69 ~~close~~million ~~some~~of ~~coal-fired~~costs ~~energy~~incurred ~~centers~~to ~~earlier~~license ~~than~~additional ~~planned,~~nuclear ~~which~~generation ~~could~~at ~~lead~~its toCallaway ~~possible~~energy ~~impairment~~site. If ofefforts ~~assets~~are ~~and~~permanently ~~reduced revenues.~~abandoned Asor amanagement ~~result,~~concludes ~~mandatory~~it ~~limits~~is ~~could~~probable ~~have~~the acosts ~~material~~incurred ~~adverse~~will ~~impact~~be ondisallowed ~~Ameren’s~~in rates, ~~Ameren~~a ~~Missouri’s,~~charge ~~and~~to ~~Genco’s~~earnings ~~results~~would ofbe ~~operations,~~recognized ~~financial~~in ~~position,~~the ~~and~~period ~~liquidity.~~in which that determination was made.

~~The~~We ~~construction~~may ~~of,~~not ~~and~~be ~~capital~~able ~~improvements~~ to, ~~Ameren’s,~~execute ~~Ameren~~our ~~Missouri’s and Ameren Illinois’~~ electric ~~and~~transmission ~~natural~~investment ~~gas utility~~plans ~~infrastructure as well as to Ameren’s~~ and ~~Genco’s~~realize ~~merchant generation facilities involve substantial risks. These risks include escalating costs, unsatisfactory performance by~~ the ~~projects~~expected ~~when completed, the inability to complete projects as scheduled, cost disallowances by regulators and the inability to earn a reasonable~~ return on ~~invested~~those ~~capital, any of which could result in higher costs and the closure of facilities~~investments.

~~Over~~Ameren, ~~the~~through ~~next~~ATXI ~~five~~and ~~years, the~~ Ameren ~~Companies~~Illinois, ~~will~~is ~~incur~~allocating significant additional capital ~~expenditures~~resources to ~~comply~~electric ~~with~~transmission ~~existing~~investments. ~~and~~This ~~known~~allocation ~~environmental regulations~~of ~~and~~capital toresources ~~make~~is ~~investments~~based inon ~~their~~FERC's ~~electric~~regulatory framework and ~~natural~~a ~~gas~~rate ~~utility~~of ~~infrastructure~~return ~~and~~on ~~their~~common ~~merchant~~equity ~~generation~~that ~~facilities~~is currently higher than allowed by our state commissions. ~~The~~However ~~Ameren~~the ~~Companies~~FERC ~~estimate~~regulatory ~~that~~framework ~~they~~and ~~will~~rate ~~incur~~of upreturn is subject to ~~$8.3 billion~~change ~~(Ameren~~and ~~Missouri~~the –regulatory upframework tomay ~~$3.6 billion;~~not ~~Ameren~~be ~~Illinois~~as –favorable, upor tothe $3rate of return may be lower, in the future.3 ~~billion;~~A ~~Genco~~significant –number upof our planned electric transmission investments have been approved by MISO as three separate multi-value projects to $0be constructed by ATXI.4 ~~billion;~~The ~~other –~~total upinvestment in these three projects is expected to be more than $1.03 billion) with the last of ~~capital~~these ~~expenditures~~projects ~~during~~expected ~~the~~to ~~period~~be ~~2012~~completed ~~through~~in ~~2016~~2019. ~~These~~Any ~~expenses~~failure ~~include~~by ~~construction~~Ameren ~~expenditures,~~to ~~capitalized interest~~complete orthese ~~allowance~~three ~~for~~projects ~~funds~~as ~~used~~designed ~~during~~on ~~construction~~time and within projected cost estimates, ~~compliance~~could ~~with~~adversely ~~environmental~~affect ~~standards~~our results of operations, financial position, and ~~compliance~~liquidity. ~~with~~Future investments may be affected by changes in FERC policy regarding the ~~requirements~~utilities' right of ~~the~~first ~~IEIMA~~refusal to construct new transmission projects within their service territory. In the future, Ameren may not be able to invest in electric transmission to the extent desired.

~~Investments~~Our incounterparties ~~Ameren’s~~may ~~regulated~~not ~~operations~~meet ~~are~~their ~~expected~~obligations to ~~be recoverable from ratepayers~~us, ~~but are subject to prudency reviews~~ and ~~regulatory~~Ameren ~~lag.~~affiliates ~~The~~may ~~recoverability~~not ofmeet ~~amounts~~their ~~expended~~obligations into ~~merchant generation~~each ~~operations will depend upon market prices for capacity and energy~~other.

~~The~~We ~~ability~~are ofexposed ~~the Ameren Companies~~ to ~~complete facilities~~the ~~under~~risk ~~construction~~that ~~successfully,~~counterparties ~~and~~ to ~~complete~~various ~~future~~arrangements ~~projects~~who ~~within~~owe ~~established~~us ~~estimates~~money, iscredit, ~~contingent~~energy, ~~upon~~coal, ~~many~~or ~~variables~~other ~~and~~commodities ~~subject~~or toservices ~~substantial~~will ~~risks.~~not ~~These~~be ~~variables~~able ~~include,~~to ~~but~~perform ~~are~~their ~~not~~obligations ~~limited to~~or, ~~project~~with ~~management expertise~~respect ~~and~~to ~~escalating~~our ~~costs~~credit ~~for materials~~facilities, ~~labor,~~will ~~and~~fail ~~environmental~~to ~~compliance.~~honor ~~Delays~~their incommitments. ~~obtaining~~Should ~~permits,~~the ~~shortages~~counterparties into ~~materials~~commodity ~~and~~arrangements ~~qualified~~fail ~~labor,~~to ~~suppliers and contractors who do not~~ perform, aswe ~~required~~might ~~under~~be ~~their~~forced ~~contracts,~~to ~~changes~~replace ~~in the~~or ~~scope~~to ~~and~~sell ~~timing of projects,~~ the ~~inability~~underlying tocommitment ~~raise~~at ~~capital~~then-current onmarket ~~favorable~~prices. ~~terms,~~Should orthe ~~other~~lenders ~~events~~under ~~beyond~~ our ~~control~~credit ~~that~~facilities ~~could~~fail ~~occur~~to ~~may~~perform, ~~materially affect~~ the ~~schedule,~~level ~~cost, and performance~~ of ~~these~~borrowing ~~projects.~~capacity ~~With~~under ~~respect~~those toarrangements ~~capital~~would ~~spent~~decrease, ~~for pollution~~unless ~~control~~we ~~equipment,~~were ~~there~~able isto afind ~~risk~~replacement ~~that~~lenders ~~electric~~to ~~generating~~assume ~~plants~~the ~~will~~nonperforming ~~not~~lender’s becommitment. ~~permitted~~In tosuch ~~continue~~an toevent, ~~operate~~we ifmight ~~pollution~~incur ~~control~~losses, ~~equipment~~or isour ~~not~~results ~~installed~~of byoperations, ~~prescribed~~financial ~~deadlines~~position, orand ~~does~~liquidity ~~not~~could ~~perform~~otherwise asbe ~~expected.~~adversely ~~Should any~~ affected.

~~such~~Certain ~~construction~~of ~~efforts be unsuccessful,~~ the Ameren Companies ~~could~~have beobligations ~~subject~~ to ~~additional~~other ~~costs~~Ameren ~~and~~Companies toor ~~the~~other ~~loss~~Ameren ofsubsidiaries ~~their~~as ~~investment~~a inresult ~~the~~of ~~project~~transactions orinvolving ~~facility.~~energy, ~~The~~coal, ~~Ameren~~other ~~Companies~~commodities ~~may~~and ~~also be~~services, ~~required~~borrowing tofrom ~~purchase~~the ~~electricity~~money ~~for~~pools, ~~their~~and ~~customers~~as ~~until~~a ~~the~~result ~~projects~~of ~~are~~hedging ~~completed~~transactions. ~~All~~If ofone ~~these~~Ameren ~~risks~~entity ~~may~~failed ~~have~~to aperform ~~material~~under ~~adverse~~any ~~effect on the Ameren Companies’ results~~ of ~~operations~~these arrangements, ~~financial~~other ~~position,~~Ameren ~~and~~entities ~~liquidity.~~might incur

~~Our counterparties may not meet their obligations to us.~~ 21

WeTable are exposed to the risk that counterparties to various arrangements who owe us money, credit, energy, coal, or other commodities or services will not be able to perform their obligations or, with respect to our credit facilities, will fail to honor their commitments. Should the counterparties to commodity arrangements fail to perform, we might be forced to replace or to sell the underlying commitment at then-current market prices. Should the lenders under our credit facilities fail to perform, the level of borrowing capacity under those arrangements would decrease, unless we were able to find replacement lenders to assume the nonperforming lender’s commitment. In such an event, we might incur losses, or our results of operations, financial position, and liquidity could otherwise be adversely affected. Contents

~~Certain~~losses. ofTheir ~~the~~results ~~Ameren Companies~~of ~~have~~operations, ~~obligations~~financial toposition, ~~other~~and ~~Ameren~~liquidity ~~Companies~~could orbe ~~other~~adversely ~~Ameren~~affected, ~~subsidiaries~~resulting asin athe ~~result~~nondefaulting ofAmeren ~~transactions~~entity ~~involving~~being ~~energy,~~unable ~~coal,~~to ~~other~~meet ~~commodities~~its ~~and services~~obligations, ~~borrowing~~including ~~from~~to ~~the~~unrelated ~~money~~third ~~pools, and as a result of hedging transactions~~parties. Ameren If(parent) ~~one Ameren~~may ~~entity~~itself ~~failed~~have to ~~perform~~fulfill ~~under~~its ~~any~~subsidiary ofobligations ~~these~~based ~~arrangements,~~on ~~other~~guarantees ~~Ameren~~it ~~entities~~has ~~might~~entered ~~incur~~into ~~losses.~~on ~~Their~~behalf ~~results~~ of ~~operations,~~its ~~financial~~subsidiaries. ~~position,~~See ~~and~~Note ~~liquidity~~14 ~~could~~- beRelated ~~adversely~~Party ~~affected,~~Transactions ~~resulting~~under inPart ~~the~~II, ~~nondefaulting~~Item ~~Ameren~~8 ~~entity~~for ~~being unable~~information toon ~~meet~~Ameren ~~its~~(parent) ~~obligations, including to unrelated third parties~~guarantees.

Increasing costs associated with our defined benefit retirement and postretirement plans, health care plans, and other employee benefits could ~~materially~~ adversely affect our results of operations, financial position, and liquidity.

We offer defined benefit retirement and postretirement plans that cover substantially all of our employees. Assumptions related to future costs, returns on investments, interest rates, and other actuarial matters have a significant impact on our earnings and funding requirements. Ameren expects to fund its pension plans at a level equal to the greater of the pension expense or the legally required minimum contribution. Considering Ameren’s assumptions at December 31, ~~2011~~2012, its investment performance in ~~2011~~2012, and its pension funding policy, Ameren expects to make annual contributions of $9060 million to $150 million in each of the next five years, with aggregate estimated contributions of $~~580~~550 million. We expect Ameren Missouri’s, and Ameren Illinois’, ~~and Genco’s~~ portion of the future funding requirements to be 5150%, ~~33%,~~ and 1240%, respectively. These amounts are estimates. They may change with actual investment performance, changes in interest rates, changes in our assumptions, changes in government regulations, and any voluntary contributions.

20In addition to the costs of our retirement plans, the costs of providing health care benefits to our employees and retirees have increased in recent years. We believe that our employee benefit costs, including costs of health care plans for our employees and former employees, will continue to rise. The increasing costs and funding requirements associated with our defined benefit retirement plans, health care plans, and other employee benefits could increase our financing needs and otherwise materially adversely affect our results of operations, financial position, and liquidity.

~~Table~~Our electric generation, transmission and distribution facilities are subject to operational risks that could adversely affect our results of ~~Contents~~operations, financial position, and liquidity.

~~may~~The ~~change~~Ameren ~~with~~Companies’ ~~actual~~financial ~~investment~~ performance depends on the successful operation of electric generation, ~~changes~~transmission, and distribution facilities. Operation of electric generation, transmission, and distribution facilities involves many risks, including:

in• ~~interest~~facility ~~rates,~~shutdowns ~~changes~~due into ~~our assumptions,~~operator ~~changes~~error inor ~~government~~a ~~regulations,~~failure ~~and~~of ~~any~~equipment ~~voluntary~~or ~~contributions.~~ processes;

In• ~~addition~~longer-than-anticipated tomaintenance ~~the costs of our retirement plans, the costs of providing health care benefits to our employees~~ outages;

~~and~~• ~~retirees~~older ~~have~~generating ~~increased~~equipment inmay ~~recent~~require ~~years.~~significant Weexpenditures ~~believe that our employee benefit costs, including costs of health care plans for our employees and former employees, will continue~~ to ~~rise.~~keep ~~The~~it ~~increasing~~operating ~~costs~~at ~~and~~peak funding requirements associated with our defined benefit retirement plans, health care plans, and other employee benefits could increase our financing needs and otherwise materially adversely affect our results of operations, financial position, and liquidity. efficiency;

~~Our~~• ~~electric~~disruptions ~~generating,~~in ~~transmission~~the ~~and~~delivery ~~distribution~~of ~~facilities~~fuel ~~are~~or ~~subject~~lack ~~to operational risks that could materially adversely affect our results~~ of ~~operations, financial position, and liquidity.~~ adequate

~~The Ameren Companies’ financial performance depends on the successful operation of electric generating~~inventories, ~~transmission,~~including ~~and distribution~~ultra-low-sulfur ~~facilities.~~coal ~~Operation~~used offor ~~electric~~Ameren ~~generating,~~Missouri’s ~~transmission,~~compliance ~~and~~with ~~distribution~~environmental ~~facilities involves many risks, including:~~ regulations;

Ÿ• ~~facility~~lack ~~shutdowns~~of ~~due~~water, tothrough ~~operator~~low ~~error~~river levels or aother ~~failure~~causes, ofrequired ~~equipment~~for orcooling ~~processes~~plant operations;

Ÿ• ~~longer-than-anticipated~~labor ~~maintenance outages~~disputes;

Ÿ• ~~older~~inability ~~generating~~to ~~equipment~~comply ~~may~~with ~~require~~regulatory ~~significant~~or ~~expenditures~~permit torequirements, ~~keep~~including itthose ~~operating~~relating atto ~~peak~~environmental ~~efficiency~~contamination;

Ÿ• disruptions in the delivery of ~~fuel or lack of adequate inventories~~electricity, including ~~ultra-low-sulfur~~impacts ~~coal~~on ~~used~~us ~~for~~or ~~Ameren~~our ~~Missouri’s compliance with environmental regulations~~customers;

Ÿ• ~~lack~~handling and storage of ~~water~~fossil-fuel ~~for~~combustion ~~cooling~~byproducts, ~~plant~~such ~~operations~~as CCR;

Ÿ• ~~labor~~unusual ~~disputes~~or adverse weather conditions, including severe storms, droughts, floods and tornadoes;

Ÿ• ~~inability~~a toworkplace ~~comply~~accident ~~with~~that ~~regulatory~~might result in injury or ~~permit~~loss ~~requirements~~of life, ~~including~~extensive ~~those~~property ~~relating~~damage, toor environmental ~~contamination~~damage;

Ÿ• ~~disruptions~~cybersecurity inrisk, ~~the~~including ~~delivery~~loss of ~~electricity~~operational control of our energy centers and our electric and natural gas transmission and distribution systems and/or loss of data, ~~including~~such ~~impacts~~as onutility uscustomer data, account information, and intellectual property through insider or ~~our~~outsider ~~customers~~actions;

Ÿ• ~~handling~~catastrophic ~~and~~events ~~storage~~such ofas ~~fossil-fuel~~fires, ~~combustion~~explosions, ~~byproducts~~pandemic health events, ~~such~~or asother ~~CCR~~similar occurrences;

Ÿ• ~~unusual~~limitations oron ~~adverse~~amounts ~~weather~~of ~~conditions,~~insurance ~~including~~available ~~severe~~to ~~storms~~cover losses that might arise in connection with operating our electric generation, ~~droughts~~transmission, ~~floods~~ and ~~tornados~~distribution facilities; and

Ÿ• aother ~~workplace~~unanticipated ~~accident~~operations ~~that~~and ~~might~~maintenance ~~result~~expenses inand ~~injury or loss of life, extensive property damage, or environmental damage;~~liabilities.

ŸOur ~~cybersecurity~~natural ~~risk,~~gas ~~including~~distribution ~~loss~~and ofstorage ~~operational~~activities ~~control~~involve ofnumerous ~~our~~risks ~~energy~~that ~~centers~~may ~~and~~result ~~our~~in ~~electric~~accidents and ~~natural~~other ~~gas~~operating ~~transmission~~risks and ~~distribution~~costs ~~systems~~that ~~and/or~~could ~~loss~~adversely ofaffect ~~data,~~our ~~such~~results asof ~~utility customer data~~operations, ~~account~~financial ~~information~~position, and ~~intellectual property through insider or outsider actions;~~liquidity.

ŸInherent ~~catastrophic~~in ~~events~~our natural gas distribution and storage activities are a variety of hazards and operating risks, such as ~~fires~~leaks, accidental explosions, ~~pandemic~~mechanical ~~health~~problems ~~events~~and cybersecurity risks, orwhich could cause substantial financial losses. In addition, these risks could result in serious injury to employees and nonemployees, loss of human life, significant damage to property, environmental pollution, and impairment of our operations, which in turn could lead to substantial losses for us. In accordance with customary industry practice, we maintain insurance against some, but not all, of these risks and losses. The location of distribution lines and storage facilities near populated areas, including residential areas, commercial business centers, industrial sites, and other ~~similar~~public ~~occurrences;~~gathering places, could increase the level of damages resulting from these risks. The occurrence of any of these events not fully covered by insurance could materially adversely affect our results of operations, financial position, and liquidity.

ŸWe ~~limitations~~are onsubject ~~amounts of insurance available~~ to ~~cover~~federal ~~losses~~regulatory ~~that~~compliance ~~might~~and ~~arise~~proceedings, inwhich ~~connection~~increase ~~with operating~~ our ~~electric~~risk ~~generating,~~of ~~transmission,~~regulatory penalties and ~~distribution~~other ~~facilities; and~~sanctions.

ŸThe ~~other~~Energy ~~unanticipated~~Policy ~~operations~~Act ~~and~~of ~~maintenance~~2005 ~~expenses~~increased FERC’s civil penalty authority for violation of FERC statutes, rules, and ~~liabilities~~orders, including FERC Reliability Standards. FERC can impose

~~We are subject to federal regulatory compliance and proceedings, which increase our risk of regulatory penalties and other sanctions.~~ 22

~~The~~Table ~~Energy Policy Act~~ of 2005 increased FERC’s civil penalty authority for violation of FERC statutes, rules, and orders, including FERC Reliability Standards. FERC can impose penalties of $1 million per violation per day. Under the Energy Policy Act of 2005, the Ameren Companies, as owners and operators of bulk power transmission systems and/or electric generation facilities, are subject to mandatory NERC reliability standards, including cybersecurity standards. Compliance with these mandatory reliability standards may subject the Ameren Companies to higher operating costs and may result in increased capital expenditures. If the Ameren Companies were found not to be in compliance with these mandatory reliability standards or other FERC statutes, rules and orders, the Ameren Companies could incur substantial monetary penalties and other sanctions, which could adversely affect our results of operations, financial position, and liquidity. Contents

~~Our~~penalties ~~natural~~of ~~gas~~$1 ~~distribution~~million per violation per day. Under the Energy Policy Act of 2005, the Ameren Companies, as owners and ~~storage activities~~operators ~~involve~~of ~~numerous~~bulk ~~risks~~power ~~that~~transmission systems and/or electric energy centers, are subject to mandatory NERC reliability standards, including cybersecurity standards. Compliance with these mandatory reliability standards may subject the Ameren Companies to higher operating costs and may result in ~~accidents~~increased ~~and~~capital expenditures. If the Ameren Companies were found not to be in compliance with these mandatory reliability standards or other ~~operating~~FERC ~~risks~~statutes, rules and ~~costs~~orders, ~~that~~the Ameren Companies could ~~materially~~incur substantial monetary penalties and other sanctions, which could adversely affect our results of operations, financial position, and liquidity. FERC also conducts audits and reviews of Ameren Missouri's, Ameren Illinois', and ATXI's accounting records to assess the accuracy of its formula rate-making process and has the ability to require retroactive refunds to customers for previously billed amounts, with interest.

~~Inherent~~Even inthough ~~our~~agreements ~~natural~~have ~~gas~~been ~~distribution~~reached ~~and~~with ~~storage~~the ~~activities~~state ~~are a variety~~ of ~~hazards~~Missouri and ~~operating~~the ~~risks~~FERC, ~~such~~the asbreach ~~leaks,~~of ~~accidental explosions,~~the ~~mechanical~~upper ~~problems~~reservoir ~~and cybersecurity risks, which could cause substantial financial losses. In addition, these risks could result in serious injury to employees and nonemployees, loss~~ of ~~human~~Ameren ~~life,~~Missouri’s ~~significant~~Taum ~~damage~~Sauk topumped-storage ~~property, environmental~~hydroelectric ~~pollution,~~energy ~~and~~center ~~impairment of our operations, which in turn~~ could ~~lead~~continue to ~~substantial~~have ~~losses~~a ~~for~~material ~~us.~~adverse Ineffect ~~accordance~~on ~~with~~Ameren’s ~~customary industry practice, we maintain insurance against some, but not all, of these risks~~ and ~~losses.~~Ameren ~~The location~~Missouri’s of distribution lines and storage facilities near populated areas, including residential areas, commercial business centers, industrial sites, and other public gathering places, could increase the level of damages resulting from these risks. The occurrence of any of these events not fully covered by insurance could materially adversely affect our results of operations, ~~financial position~~liquidity, and ~~liquidity.~~financial condition.

~~Even~~In ~~though~~December ~~agreements~~2005, ~~have~~there ~~been~~was ~~reached~~a ~~with the state of Missouri and the FERC, the~~ breach of the upper reservoir ofat Ameren Missouri’s Taum Sauk pumped-storage hydroelectric energy center. ~~could~~This ~~continue to~~resulted ~~have~~in asignificant ~~material~~flooding ~~adverse~~in ~~effect~~the onlocal ~~Ameren’s~~area, ~~and~~which damaged a state park. Ameren Missouri’s ~~results~~has ofsettled ~~operations,~~with ~~liquidity,~~FERC and ~~financial~~the ~~condition.~~state of Missouri all issues associated with the December 2005 Taum Sauk incident.

InAmeren ~~December~~Missouri ~~2005~~had liability insurance coverage for the Taum Sauk incident, ~~there~~subject ~~was~~to acertain ~~breach~~limits ofand deductibles. Currently, Ameren Missouri has filed separate lawsuits against two different liability insurance providers claiming that the ~~upper~~insurance ~~reservoir~~companies atbreached their duty to indemnify Ameren Missouri for the losses experienced from the incident. Ameren’s ~~Taum~~and ~~Sauk~~Ameren ~~pumped-storage~~Missouri’s ~~hydroelectric~~results ~~energy~~of ~~center.~~operations, ~~This~~financial ~~resulted~~position, inand ~~significant~~liquidity ~~flooding~~could inbe ~~the~~adversely ~~local~~affected ~~area~~if Ameren Missouri’s remaining liability insurance claims of $68 million as of December 31, ~~which~~2012, ~~damaged~~are ~~a state~~not ~~park.~~paid by insurers.

21Ameren's Merchant Generation energy centers must compete for the sale of energy and capacity, which exposes that business to price risks.

~~Table~~All of ~~Contents~~Ameren's Merchant Generation energy centers compete for the sale of energy and capacity in the competitive energy markets.

~~Ameren~~To ~~Missouri~~the ~~settled~~extent ~~with~~that ~~FERC~~electricity ~~and~~generated by these energy centers is not under a fixed-price contract to be sold, the ~~state~~revenues and results of ~~Missouri~~operations ~~all~~of ~~issues~~these ~~associated~~Merchant ~~with~~Generation subsidiaries generally depend on the ~~December~~prices ~~2005~~that ~~Taum~~can ~~Sauk~~be ~~incident.~~obtained for energy and capacity in Illinois and adjacent markets by Marketing Company.

~~Ameren~~Market ~~Missouri~~prices ~~had liability insurance coverage~~ for ~~the~~energy ~~Taum Sauk incident, subject to certain limits~~ and ~~deductibles.~~capacity Inmay ~~June~~fluctuate ~~2010,~~substantially ~~Ameren Missouri~~over ~~sued~~both ~~one of its liability insurance providers claiming~~ the ~~insurance~~short ~~company~~and ~~breached~~long ~~its duty to indemnify Ameren Missouri for the losses experienced from the incident~~term. ~~Ameren’s~~For ~~and Ameren Missouri’s results of operations~~example, ~~financial~~ ~~position and liquidity could be adversely affected if Ameren Missouri’s remaining liability insurance claims of $68 million as of December 31, 2011, are not paid by insurers.~~

~~Ameren~~market ~~Missouri~~prices ~~requested~~for ~~the~~power ~~recovery~~have ofdecreased ~~all~~over ~~costs~~the ofpast ~~enhancements,~~several oryears. ~~costs~~Demand ~~that~~for ~~would~~electricity ~~have~~and ~~been~~fuel ~~incurred~~can ~~absent~~fluctuate ~~the breach~~dramatically, ~~related~~creating toperiods ~~the rebuilding~~ of ~~the~~substantial ~~Taum~~undersupply ~~Sauk~~or ~~energy~~oversupply. ~~center~~During inperiods ~~excess~~ of ~~amounts recovered from property insurance. In its July 2011 electric rate order~~oversupply, ~~the~~prices ~~MoPSC~~might ~~disallowed~~be ~~Ameren Missouri’s request~~depressed. ~~Consequently~~Also, inat ~~2011,~~times ~~Ameren~~legislators ~~Missouri~~or ~~recorded~~regulators awith ~~pretax charge~~jurisdiction toover ~~earnings~~wholesale ofand ~~$89~~retail ~~million.~~energy ~~Ameren~~commodity ~~Missouri~~and ~~has~~transportation ~~appealed~~rates ~~this~~may ~~disallowance~~impose toprice ~~the~~limitations, ~~Missouri~~bidding ~~Court of Appeals~~rules, ~~Western~~and ~~District.~~other ~~Ameren~~mechanisms ~~Missouri~~to ~~cannot~~address ~~predict~~volatility ~~the~~and ~~ultimate~~other ~~outcome~~issues ofin ~~its~~these ~~appeal~~markets.

~~Until~~For ~~Ameren’s~~power ~~remaining~~products ~~liability~~sold ~~insurance~~in ~~claims~~advance, ~~and~~contract ~~litigation~~prices are ~~resolved,~~influenced weboth ~~are~~by ~~unable~~market toconditions ~~determine~~and by contract terms such as damage provisions, credit support requirements, and the ~~total~~number ~~impact~~of available counterparties interested in contracting for the ~~breach~~desired ~~could have~~forward period. Depending on ~~Ameren~~differences between market factors at the time of contracting versus current conditions, Marketing Company’s ~~and~~contract ~~Ameren~~portfolio ~~Missouri~~may have average contract prices greater than or less than current market prices, including at the expiration of the contracts, which could affect Ameren’s results of operations, financial ~~position,~~condition and liquidity ~~beyond those amounts already recognized~~.

~~Genco’s~~Any ~~and~~unhedged ~~AERG’s~~forecasted ~~electric~~generation ~~energy~~will ~~centers~~be ~~must~~exposed ~~compete~~to ~~for~~market prices at the ~~sale~~time of ~~energy~~sale. ~~and~~As ~~capacity~~a result, ~~which~~any ~~exposes~~new ~~them~~physical toor financial power sales may be at price ~~risks.~~levels lower than previously experienced and lower than the value of existing hedged sales.

~~All~~Among ofthe ~~Genco’s~~factors ~~and~~that ~~AERG’s~~could ~~energy~~influence ~~centers~~such ~~compete~~prices ~~for~~(all ~~the sale~~ of ~~energy~~which ~~and~~are ~~capacity~~beyond inour ~~the~~control ~~competitive~~to ~~energy~~a ~~markets.~~significant degree) are:

To• ~~the~~current ~~extent that electricity generated by these energy centers is not under a fixed-price contract to be sold, the revenues~~ and ~~results~~future ~~of operations~~delivered ofmarket ~~these Merchant Generation subsidiaries generally depend on the~~ prices ~~that can be obtained~~ for ~~energy~~natural ~~and~~gas, ~~capacity~~coal, ~~in Illinois~~ and ~~adjacent~~related ~~markets~~transportation ~~by Marketing Company.~~ costs;

~~Market~~• ~~prices~~current ~~for energy~~ and ~~capacity~~forward ~~may~~prices ~~fluctuate substantially, sometimes over relatively short periods of time, and at other times experience sustained increases or decreases. Demand~~ for ~~electricity~~the ~~and~~sale ~~fuel can fluctuate dramatically, creating periods~~ of substantial undersupply or oversupply. During periods of oversupply, prices might be depressed. Also, at times legislators or regulators with jurisdiction over wholesale and retail energy commodity and transportation rates may impose price limitations, bidding rules, and other mechanisms to address volatility and other issues in these markets. electricity;

~~For~~• ~~power~~current ~~products~~and ~~sold~~future inprices ~~advance,~~for ~~contract~~emission ~~prices~~allowances ~~are~~that ~~influenced~~may ~~both~~be byrequired ~~market~~to ~~conditions~~operate ~~and~~the byfossil-fuel-fired ~~contract~~ electric energy centers in compliance with environmental laws and permits;

~~terms~~• ~~such as damage provisions, credit support requirements, and~~ the ~~number~~extent of ~~available~~additional ~~counterparties~~supplies ~~interested in contracting for the desired forward period. Depending on differences between market factors at the time~~ of ~~contracting~~electric ~~versus~~energy from current ~~conditions,~~competitors ~~Marketing Company’s contract portfolio may have average contract prices greater than~~ or ~~less~~new ~~than current~~ market ~~prices, including at the expiration of the contracts, which could significantly affect Ameren’s and Genco’s results of operations, financial condition and liquidity.~~ entrants;

~~Market~~• ~~prices for power have decreased over~~ the ~~past~~regulatory ~~three~~and ~~years. During 2012, the~~ market ~~price~~structures ~~for~~developed ~~power~~ for ~~delivery~~evolving inMidwest ~~the~~energy ~~current~~markets, ~~year~~including ~~has~~a ~~declined~~capacity ~~below 2011 levels because of factors such as declining natural gas prices and the stay of the CSAPR. Any unhedged forecasted generation will be exposed to~~ market ~~prices~~in ~~at the time of sale. As a result, any new physical or financial power sales may be at price levels lower than previously experienced and lower than the value of existing hedged sales.~~ MISO;

~~Among~~• ~~the~~changes ~~factors~~enacted ~~that~~by ~~could~~the ~~influence~~Illinois ~~such~~legislature, ~~prices~~the ~~(all~~ICC, ofthe ~~which~~IPA, ~~are~~or ~~beyond~~other ~~our~~government ~~control~~agencies towith arespect ~~significant~~to ~~degree)~~power ~~are:~~procurement procedures;

Ÿ• ~~current~~the ~~and~~potential ~~future delivered market prices~~ for ~~natural~~reregulation ~~gas,~~of ~~coal,~~generation ~~and~~in ~~related~~some ~~transportation costs~~states;

Ÿ• ~~current~~future pricing for, and ~~forward~~availability ~~prices~~of, ~~for~~services on transmission systems, and the ~~sale~~effect of ~~electricity~~RTOs and export energy transmission constraints, which could limit our ability to sell energy in our markets;

Ÿ• ~~current~~the ~~and~~growth ~~future~~rate ~~prices~~or ~~for~~decline ~~emission~~in ~~allowances~~electricity ~~that~~usage ~~may~~as bea ~~required~~result toof ~~operate~~population ~~the~~changes, ~~fossil~~regional ~~fuel-fired~~economic ~~electric~~conditions, ~~energy~~and ~~centers~~the inimplementation ~~compliance~~of ~~with~~energy-efficiency ~~environmental laws~~ and ~~permits~~conservation programs;

Ÿ• ~~the~~climate ~~extent~~conditions ofin ~~additional~~the ~~supplies~~Midwest ofmarket ~~electric~~and ~~energy~~major ~~from~~natural ~~current competitors or new market entrants~~disasters; and

Ÿ• ~~the~~environmental ~~regulatory~~laws and ~~market~~regulations ~~structures~~or ~~developed~~delays ~~for~~in ~~evolving~~their ~~Midwest~~effective ~~energy markets, including a capacity market in MISO;~~dates.

~~Ÿ changes enacted by the Illinois legislature, the ICC, the IPA, or other government agencies with respect to power procurement procedures;~~23

ŸTable ~~the potential for reregulation~~ of ~~generation in some states;~~Contents

ŸThere ~~future~~is ~~pricing~~substantial ~~for,~~uncertainty ~~and~~concerning ~~availability~~the ofmanner, ~~services on transmission systems~~timing, and ~~the~~terms ~~effect~~ of ~~RTOs and export energy transmission constraints, which could limit~~ our ~~ability~~anticipated toexit ~~sell~~from ~~energy~~the inMerchant ~~our~~Generation ~~markets;~~business.

ŸIn ~~the~~December ~~growth~~2012, ~~rate~~Ameren ordetermined ~~decline~~that init ~~electricity~~intends ~~usage~~to, asand ait ~~result~~is ofprobable ~~population~~that ~~changes~~it will, ~~regional~~exit ~~economic~~its ~~conditions~~Merchant Generation business before the end of the previously estimated useful lives of that business's long-lived assets. However, Ameren's date and method of exit from the Merchant Generation business are currently uncertain. Exit strategies may include the sale of all or parts of Ameren's Merchant Generation business and the restructuring of all or a portion of Ameren's equity position in Genco. Once a plan of disposal is finalized, Ameren's implementation of ~~energy~~that plan may result in long-~~efficiency~~lived asset impairments, disposal-related losses, contingencies, reduction of existing deferred tax assets, and ~~conservation~~other ~~programs;~~consequences that are currently unknown to Ameren.

ŸAmeren's ~~climate~~Merchant ~~conditions~~Generation inbusiness ~~the~~is ~~Midwest~~experiencing ~~market~~a period of declining operating revenues and ~~major~~higher ~~natural~~costs ~~disasters;~~with limited available sources of external liquidity, and internal sources of liquidity available only at Ameren's discretion, which could be withheld by Ameren. Merchant Generation, including Genco, may require liquidity support from Ameren, which could adversely affect Ameren's results of operations, financial position, and liquidity.

ŸBased ~~environmental~~on ~~laws~~projections as of December 31, 2012, of its operating results and ~~regulations~~cash flows, Genco expects that, by the end of the first quarter of 2013, its interest coverage ratio will be less than the minimum ratio required for the company to borrow additional funds from external, third-party sources. Genco's indenture does not restrict intercompany borrowings from Ameren's non-state-regulated subsidiary money pool. However, borrowings from the money pool are subject to Ameren's control. If a Genco intercompany financing need were to arise, borrowings from the non-state-regulated subsidiary money pool by Genco would be dependent on consideration by Ameren of the facts and circumstances existing at that time. It is probable that during 2013 Genco will seek mid-month liquidity from Ameren to support the timing of Genco's cash flows. Ameren may decide not to provide funding to Genco should a financing need arise in 2013 or ~~delays~~in the future. Genco also has significant debt maturities beginning in ~~their~~2018. ~~effective~~If ~~dates~~Genco is unable to meet its liquidity needs, this could result in Genco accelerating asset sales, or restructuring. Genco expects to sell certain of its long-lived assets, either individually or through its put option with AERG, but the proceeds realized from any asset sale may not be adequate to satisfy Genco's liquidity needs.

22Ameren's December 2012 decision that the Merchant Generation segment is no longer a core component of its future strategy could adversely affect Ameren's results of operations, financial position, and liquidity. Ameren has begun planning to reduce, and ultimately to eliminate, the reliance of the Merchant Generation segment, including Genco, on Ameren's financial support and shared service support. Ameren's exit date from the Merchant Generation segment is uncertain. By requiring the

~~Table~~Merchant Generation segment to duplicate support services, Ameren may reduce the synergies between its business segments. Further, counterparties may not extend credit to the Merchant Generation segment, which could limit Merchant Generation revenue opportunities and may result in a need for additional liquidity to operate the business. Also, Ameren has supplied guarantees to support Marketing Company's creditworthiness with counterparties. Under these guarantees, Ameren may have to fulfill Marketing Company obligations if Marketing Company becomes unable to satisfy the counterparty obligation with its own liquidity. Ameren may also be required to supply liquidity and to contribute capital to AERG should Genco exercise its put option agreement relating to three natural-gas-fired energy centers. See Note 14 - Related Party Transactions under Part II, Item 8, of ~~Contents~~this report for additional information about the put option agreement and Ameren parent guarantees.

Ameren Missouri’s ownership and operation of a nuclear energy center creates business, financial, and waste disposal risks.

Ameren Missouri’s ownership of the Callaway energy center subjects it to the risks of nuclear generation, which include the following:

Ÿ• potential harmful effects on the environment and human health resulting from the operation of nuclear facilities and the storage, handling, and disposal of radioactive materials;

Ÿ• the lack of a permanent waste storage site;

Ÿ• limitations on the amounts and types of insurance commercially available to cover losses that might arise in connection with the Callaway energy center or other United States nuclear operations;

Ÿ• uncertainties with respect to contingencies and ~~assessment~~retrospective ~~amounts~~premium ifassessments ~~insurance~~relating ~~coverage~~to isclaims ~~inadequate~~at the Callaway energy center or any other United States nuclear energy center;

Ÿ• public and governmental concerns over the adequacy of security at nuclear energy centers;

Ÿ• uncertainties with respect to the technological and financial aspects of decommissioning nuclear energy centers at the end of their licensed lives (Ameren Missouri has submitted an application with the NRC to extend the Callaway energy center’s operating license from 2024 to 2044);

Ÿ• limited availability of fuel supply; and

Ÿ• costly and extended outages for scheduled or unscheduled maintenance and refueling.

The NRC has broad authority under federal law to impose licensing and safety requirements for nuclear energy centers. In the event of noncompliance, the NRC has the authority to impose fines or to shut down a unit, or both, depending upon its assessment of the severity of the situation, until compliance is achieved. Revised safety requirements promulgated from time to time by the NRC could necessitate substantial capital expenditures at nuclear energy centers such as Ameren Missouri’s. In addition, if a serious nuclear incident were to occur, it could have a material but indeterminable adverse effect on Ameren Missouri’s results of operations, financial condition, and liquidity. A major incident at a nuclear energy center anywhere in the world could cause the NRC to limit or prohibit the operation or relicensing of any domestic nuclear unit. An incident at a nuclear energy center anywhere in the world also could cause the NRC to impose additional conditions or requirements on the industry, which could increase costs and result in additional capital expenditures. For example, the earthquake in 2011 that affected nuclear plants in Japan is expected to result in regulatory changes in the United States that may impose additional costs on all United States nuclear plants.

Our energy risk management strategies may not be effective in managing fuel and electricity procurement and pricing risks, which could result in unanticipated liabilities or increased volatility in our earnings and cash flows. 24

WeTable are exposed to changes in market prices for natural gas, fuel, power, emission allowances, renewable energy credits, and transmission congestion. Prices for natural gas, fuel, power, emission allowances and renewable energy credits may fluctuate substantially over relatively short periods of time, and at other times exhibit sustained increases or decreases, and expose us to commodity price risk. We use short-term and long-term purchase and sales contracts in addition to derivatives such as forward contracts, futures contracts, options, and swaps to manage these risks. We attempt to manage our risk associated with Contents

~~these~~liquidity. ~~activities~~A ~~through~~major ~~enforcement~~incident at a nuclear energy center anywhere in the world could cause the NRC to limit or prohibit the operation or relicensing of ~~established~~any ~~risk~~domestic ~~limits~~nuclear unit. An incident at a nuclear energy center anywhere in the world also could cause the NRC to impose additional conditions or requirements on the industry, which could increase costs and ~~risk~~result ~~management~~in ~~procedures~~additional capital expenditures. WeFor ~~cannot~~example, ~~ensure~~the ~~that~~earthquake ~~these~~in ~~strategies~~2011 ~~will~~that beaffected ~~successful~~nuclear energy centers in ~~managing~~Japan ~~our~~has ~~pricing~~resulted ~~risk~~in orregulatory ~~that~~changes ~~they~~in ~~will~~the ~~not~~United States, and may result in ~~net~~ ~~liabilities~~future ~~because~~regulatory ofchanges, ~~future~~that ~~volatility~~may inimpose ~~these~~additional ~~markets.~~costs on all United States nuclear energy centers.

~~Although~~Our weenergy ~~routinely~~risk ~~enter~~management ~~into~~strategies ~~contracts~~may tonot ~~hedge~~be ~~our~~effective ~~exposure~~in tomanaging ~~the risks~~fuel ~~of demand~~ and ~~changes~~electricity inprocurement ~~commodity~~and ~~prices,~~pricing ~~we do not hedge the entire exposure of our operations from commodity price volatility. Furthermore~~risks, our ability to hedge our exposure to commodity price volatility depends on liquid commodity markets. To the extent that commodity markets are illiquid, we may not be able to execute our risk management strategies, which could result in ~~greater~~unanticipated ~~unhedged~~liabilities ~~positions~~or ~~than~~increased wevolatility ~~would~~in ~~prefer at a given time. To the extent that unhedged positions exist, fluctuating commodity prices can adversely affect~~ our ~~results~~earnings ~~of operations, financial position,~~ and ~~liquidity.~~cash flows.

~~Our~~We ~~facilities~~ are ~~considered~~ ~~critical~~exposed to changes in market prices for natural gas, fuel, power, emission allowances, renewable energy ~~infrastructure~~credits, and transmission congestion. Prices for natural gas, fuel, power, emission allowances and renewable energy credits may ~~therefore~~fluctuate besubstantially ~~targets~~over relatively short periods of ~~acts~~time, and at other times exhibit sustained increases or decreases, and expose us to commodity price risk. We use short-term and long-term purchase and sales contracts in addition to derivatives such as forward contracts, futures contracts, options, and swaps to manage these risks. We attempt to manage our risk associated with these activities through enforcement of ~~terrorism~~established risk limits and risk management procedures. We cannot ensure that these strategies will be successful in managing our pricing risk or that they will not result in net liabilities because of future volatility in these markets.

~~Like~~Although ~~other~~we ~~electric~~routinely ~~and~~enter ~~natural~~into ~~gas utilities~~contracts ~~and~~to ~~other~~hedge ~~merchant electric generators,~~ our ~~energy~~exposure ~~centers,~~to ~~fuel~~the ~~storage~~risks ~~facilities,~~of demand and ~~transmission~~changes ~~and~~in ~~distribution~~commodity ~~facilities~~prices, ~~may~~we bedo ~~targets~~not ofhedge ~~terrorist~~the ~~activities,~~entire ~~including~~exposure ~~cybersecurity~~of ~~attacks,~~our ~~that~~operations ~~could~~from ~~result~~commodity inprice ~~disruption~~volatility. of Furthermore, our ability to ~~produce~~hedge orour ~~distribute~~exposure ~~some~~to ~~portion~~commodity ofprice ~~our~~volatility ~~energy~~depends ~~products~~on liquid commodity markets. ~~Any~~To ~~such~~the ~~disruption~~extent ~~could~~that ~~result~~commodity inmarkets aare ~~significant~~illiquid, ~~decrease~~we inmay ~~revenues~~not orbe ~~significant~~able ~~additional~~to ~~costs~~execute ~~for~~our ~~repair~~risk management strategies, which could ~~have~~result in greater unhedged positions than we would prefer at a ~~material~~given ~~adverse~~time. ~~effect~~To onthe extent that unhedged positions exist, fluctuating commodity prices can adversely affect our results of operations, financial position, and liquidity.

Our ~~businesses~~facilities are ~~dependent~~considered oncritical ~~our~~energy ~~ability~~infrastructure toand ~~access the capital markets successfully. We~~ may ~~not~~therefore ~~have~~be ~~access~~targets toof ~~sufficient~~acts ~~capital~~of ~~in the amounts and at the times needed~~terrorism.

WeLike ~~use~~other ~~short-term~~electric and ~~long-term debt~~natural asgas autilities ~~significant~~and ~~source~~other ofmerchant ~~liquidity~~electric ~~and~~generators, ~~funding~~our ~~for~~energy ~~capital~~centers, ~~requirements~~fuel ~~not~~storage ~~satisfied~~facilities, byand ~~our~~transmission ~~operating~~and ~~cash~~distribution ~~flow~~facilities may be targets of terrorist activities, including ~~requirements~~cybersecurity ~~related~~attacks, towhich ~~future~~could ~~environmental~~result ~~compliance~~in ~~and~~disruption ~~capital~~of ~~expenditures~~our ~~required~~ability byto ~~the~~produce ~~IEIMA~~or distribute some portion of our energy products. AsAny asuch disruption could result ~~of rising~~in a significant decrease in revenues or significant additional costs ~~and~~for ~~increased~~repair, ~~capital~~which ~~and~~could adversely affect on our results of operations, ~~and~~financial ~~maintenance~~position, and liquidity.

23Our businesses are dependent on our ability to access

~~Table~~the ofcapital ~~Contents~~markets successfully. We may not have access to sufficient capital in the amounts and at the times needed.

We use short-term and long-term debt as a significant source of liquidity and funding for capital requirements not satisfied by our operating cash flow, including requirements related to future environmental compliance and capital expenditures required by the IEIMA. As a result of rising costs and increased capital and operations and maintenance expenditures, coupled with regulatory lag, we expect to continue to rely on short-term and long-term debt financing. The inability to raise debt or equity capital on favorable terms, or at all, could negatively affect our ability to maintain and to expand our businesses. After assessing our current operating performance, liquidity, and credit ratings, we believe that Ameren and its rate-regulated businesses will continue to have access to the capital markets. However, events beyond our control, such as a recession or extreme volatility in global debt or equity capital and credit markets, may create uncertainty that could increase our cost of capital or impair or eliminate our ability to access the debt, equity, or credit markets, including our ability to draw on bank credit facilities. Based on projections as of December 31, ~~2011~~2012, of ~~Genco’s~~its operating results and cash flows, weGenco ~~expect~~expects that, by the end of the first quarter of 2013, ~~Genco’s~~its interest coverage ratio will be less than the minimum ratio required ~~under its indenture~~ for the company to borrow additional funds from external, third-party sources. An inability to raise debt could adversely impact Genco’'s liquidity. Any adverse change in ~~the~~ Ameren's ~~Companies’~~or in its subsidiaries' credit ratings may reduce access to capital and trigger additional collateral postings and prepayments. Such changes may also increase the cost of borrowing and fuel, power and natural gas supply, among other things, which could have a material adverse effect on our results of operations, financial position, and liquidity. Certain of the Ameren's ~~Companies~~subsidiaries rely, in part, on Ameren for access to capital. Circumstances that limit Ameren’s access to capital, including those relating to its other subsidiaries, could impair its ability to provide those Ameren ~~Companies~~subsidiaries with needed capital. In addition, borrowings directly from Ameren and from the utility and non-state-regulated subsidiary money pools are subject to Ameren’s control, and any borrowings are dependent on consideration by Ameren of the facts and circumstances existing at the time of ~~any~~the borrowing request.

Ameren’s holding company structure could limit its ability to pay common stock dividends and to service its debt obligations.

Ameren is a holding company; therefore, its primary assets are the common stock of its subsidiaries. As a result, Ameren’s ability to pay dividends on its common stock depends on the earnings of its subsidiaries and the ability of its subsidiaries to pay dividends or otherwise transfer funds to Ameren. Similarly, Ameren’s ability to service its debt obligations is also dependent upon the earnings of operating subsidiaries and the distribution of those earnings and other payments, including payments of principal and interest under intercompany indebtedness. The payment of dividends to Ameren by its subsidiaries in turn depends on their results of operations and cash flows and other items affecting retained earnings. Ameren’s subsidiaries are separate and distinct legal entities and have no obligation, contingent or otherwise, to pay any dividends or make any other distributions (except for payments required pursuant to the terms of intercompany borrowing arrangements) to Ameren. Certain of the Ameren Companies’ financing agreements and articles of incorporation, in addition to certain statutory and regulatory requirements, may impose restrictions on the ability of such Ameren Companies to transfer funds to Ameren in the form of cash dividends, loans or advances.

~~Failure to retain and attract key officers and other skilled professional and technical employees could have an adverse effect on our operations.~~ 25

~~Our~~Table ~~businesses depend upon our ability to employ and retain key officers and other skilled professional and technical employees. A significant portion~~ of our workforce is nearing retirement, including many employees with specialized skills such as maintaining and servicing our electric and natural gas infrastructure and operating our energy centers. Any inability to retain and recruit qualified employees could adversely affect our results of operations. Contents

~~ITEM~~separate 1Band distinct legal entities and have no obligation, contingent or otherwise, to pay any dividends or make any other distributions (except for payments required pursuant to the terms of intercompany borrowing arrangements and cash payments and receipts under the tax allocation agreement) to Ameren. ~~UNRESOLVED~~Certain ~~STAFF~~of ~~COMMENTS~~the Ameren Companies’ financing agreements and articles of incorporation, in addition to certain statutory and regulatory requirements, may impose restrictions on the ability of such Ameren Companies to transfer funds to Ameren in the form of cash dividends, loans or advances.

~~None~~Failure to retain and attract key officers and other skilled professional and technical employees could adversely affect on our operations.

~~ITEM~~Our 2businesses depend upon our ability to employ and retain key officers and other skilled professional and technical employees. ~~PROPERTIES~~A significant portion of our workforce is nearing retirement, including many employees with specialized skills such as maintaining and servicing our electric and natural gas infrastructure and operating our energy centers.

~~For~~ITEM ~~information on our principal properties, see the generating facilities table below~~1B. ~~See~~UNRESOLVED ~~also~~STAFF Liquidity and Capital Resources and Regulatory Matters in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, of this report for any discussion of planned additions, replacements or transfers. See also Note 5 – Long-term Debt and Equity Financings, and Note 15 – Commitments and Contingencies under Part II, Item 8, of this report. COMMENTS

24 None.

~~Table of Contents~~26

~~The~~Table ~~following table shows what the capability~~ of ~~our energy centers is anticipated to be at the time of our expected 2012 peak summer electrical demand:~~ Contents

Primary Fuel Source	Energy Center	Location	Net Kilowatt Capability(a)
Ameren Missouri:
Coal	Labadie	Franklin County, Mo.		2,412,000
	Rush Island	Jefferson County, Mo.		1,212,000
	Sioux	St. Charles County, Mo.		966,000
	Meramec	St. Louis County, Mo.		836,000
Total coal				5,426,000
Nuclear	Callaway	Callaway County, Mo.		1,190,000
Hydroelectric	Osage	Lakeside, Mo.		240,000
	Keokuk	Keokuk, Ia.		141,000
Total hydroelectric				381,000
Pumped-storage	Taum Sauk	Reynolds County, Mo.		440,000
Oil (CTs)	Meramec	St. Louis County, Mo.		59,000
	Fairgrounds	Jefferson City, Mo.		55,000
	Mexico	Mexico, Mo.		54,000
	Moberly	Moberly, Mo.		54,000
	Moreau	Jefferson City, Mo.		54,000
	Howard Bend	St. Louis County, Mo.		39,000
Total oil				315,000
Natural gas (CTs)	Audrain(b)	Audrain County, Mo.		600,000
	Venice(c)	Venice, Ill.		491,000
	Goose Creek	Piatt County, Ill.		432,000
	Pinckneyville	Pinckneyville, Ill.		316,000
	Raccoon Creek	Clay County, Ill.		300,000
	Kinmundy(c)	Kinmundy, Ill.		208,000
	Peno Creek(b)(c)	Bowling Green, Mo.		188,000
	Meramec(c)	St. Louis County, Mo.		49,000
	Kirksville	Kirksville, Mo.		13,000
Total natural gas				2,597,000
Methane gas (CTs)	Maryland Heights	Maryland Heights, Mo.		6,000
Total Ameren Missouri				10,355,000
Merchant Generation:
Genco:
Coal	Newton	Newton, Ill.		1,198,000
	Joppa (EEI)(d)	Joppa, Ill.		1,002,000
	Coffeen	Coffeen, Ill.		895,000
Total coal				3,095,000
Natural gas (CTs)	Grand Tower	Grand Tower, Ill.		478,000
	Elgin	Elgin, Ill.		460,000
	Gibson City(c)	Gibson City, Ill.		228,000
	Joppa 7B	Joppa, Ill.		108,000
	Joppa (EEI)(d)	Joppa, Ill.		74,000
Total natural gas				1,348,000
Total Genco				4,443,000
AERG:
Coal	E.D. Edwards	Bartonville, Ill.		650,000
	Duck Creek	Canton, Ill.		410,000
Total AERG				1,060,000
Total Merchant Generation				5,503,000
Total Ameren				15,858,000

ITEM 2.PROPERTIES

~~(a)~~For ~~Net~~information ~~Kilowatt~~on ~~Capability~~our isprincipal properties, see the ~~generating~~energy ~~capacity~~center ~~available~~table below. See also Liquidity and Capital Resources and Regulatory Matters in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, of this report for ~~dispatch~~a ~~from~~discussion ~~the~~of ~~energy~~planned ~~center~~additions, ~~into~~replacements ~~the~~or ~~electric~~transfers. ~~transmission~~See ~~grid~~also Note 5 - Long-term Debt and Equity Financings, and Note 15 - Commitments and Contingencies under Part II, Item 8, of this report.

~~(b)~~The ~~There~~following ~~are~~table ~~economic~~shows ~~development~~what ~~lease~~the ~~arrangements~~capability ~~applicable~~of our energy centers is anticipated to ~~these~~be ~~CTs.~~at the time of our expected 2013 peak summer electrical demand:



Primary Fuel Source	Energy Center	Location	Net Kilowatt Capability^(a)
Ameren Missouri:
Coal	Labadie	Franklin County, Mo.	2,374,000
	Rush Island	Jefferson County, Mo.	1,182,000
	Sioux	St. Charles County, Mo.	972,000
	Meramec	St. Louis County, Mo.	833,000
Total coal			5,361,000
Nuclear	Callaway	Callaway County, Mo.	1,194,000
Hydroelectric	Osage	Lakeside, Mo.	240,000
	Keokuk	Keokuk, Ia.	140,000
Total hydroelectric			380,000
Pumped-storage	Taum Sauk	Reynolds County, Mo.	440,000
Oil (CTs)	Meramec	St. Louis County, Mo.	54,000
	Fairgrounds	Jefferson City, Mo.	54,000
	Mexico	Mexico, Mo.	53,000
	Moberly	Moberly, Mo.	53,000
	Moreau	Jefferson City, Mo.	53,000
	Howard Bend	St. Louis County, Mo.	39,000
Total oil			306,000
Natural gas (CTs)	Audrain^(b)	Audrain County, Mo.	592,000
	Venice^(c)	Venice, Ill.	487,000
	Goose Creek	Piatt County, Ill.	426,000
	Pinckneyville	Pinckneyville, Ill.	312,000
	Raccoon Creek	Clay County, Ill.	296,000
	Kinmundy^(c)	Kinmundy, Ill.	206,000
	Peno Creek^(b)(c)	Bowling Green, Mo.	188,000
	Meramec^(c)	St. Louis County, Mo.	48,000
	Kirksville	Kirksville, Mo.	12,000
Total natural gas			2,567,000
Methane gas (CTs)	Maryland Heights	Maryland Heights, Mo.	8,000
Total Ameren Missouri			10,256,000
Merchant Generation:
Genco:
Coal	Newton	Newton, Ill.	1,215,000
	Joppa (EEI)^(d)	Joppa, Ill.	1,002,000
	Coffeen	Coffeen, Ill.	895,000
Total coal			3,112,000
Natural gas (CTs)	Grand Tower	Grand Tower, Ill.	478,000
	Elgin	Elgin, Ill.	460,000
	Gibson City^(c)	Gibson City, Ill.	228,000
	Joppa 7B	Joppa, Ill.	110,000
	Joppa (EEI)^(d)	Joppa, Ill.	74,000
Total natural gas			1,350,000
Total Genco			4,462,000
AERG:
Coal	E.D. Edwards	Bartonville, Ill.	650,000
	Duck Creek	Canton, Ill.	410,000
Total AERG			1,060,000
Total Merchant Generation			5,522,000
Total Ameren			15,778,000

(da) ~~Genco~~Net ~~owns~~kilowatt ancapability ~~80%~~is ~~interest~~the ingenerating ~~EEI.~~capacity ~~This~~available ~~table~~for ~~reflects~~dispatch from the ~~full~~energy ~~capability~~center ofinto ~~EEI’s~~the ~~facilities~~electric transmission grid.

25(b) There are economic development lease arrangements applicable to these CTs.

~~Table~~(c) ofThese ~~Contents~~CTs have the capability to operate on either oil or natural gas (dual fuel).

~~The~~(d) ~~following~~Genco ~~table~~owns ~~presents~~an ~~electric~~80% ~~and~~interest ~~natural~~in ~~gas~~EEI. ~~utility-related~~This ~~properties~~table ~~for~~reflects ~~Ameren Missouri~~the ~~and~~full ~~Ameren~~capability ~~Illinois as~~ of ~~December 31,~~EEI’s ~~2011:~~ facilities.

	AmerenMissouri			AmerenIllinois
Circuit miles of electric transmission lines(a)		2,956			4,506
Circuit miles of electric distribution lines		33,256			45,884
Circuit miles of electric distribution lines underground		23	%		15	%
Miles of natural gas transmission and distribution mains		3,275			18,126
Propane-air plants		1			-
Underground gas storage fields		-			12
Billion cubic feet of total working capacity of underground gas storage fields		-			24

~~(a)~~Table ~~ATXI and EEI own 29 miles and 42 miles~~ of ~~transmission lines, respectively, not reflected in this table.~~Contents

~~Our~~The ~~other~~following ~~properties~~table ~~include~~presents ~~office~~electric ~~buildings,~~and ~~warehouses,~~natural ~~garages,~~gas utility-related properties for Ameren Missouri and ~~repair~~Ameren ~~shops.~~Illinois as of December 31, 2012:

With only a few exceptions, we have fee title to all principal plants and other units of property material to the operation of our businesses, and to the real property on which such facilities are located (subject to mortgage liens securing our outstanding first mortgage bonds and to certain permitted liens and judgment liens). The exceptions are as follows:



	Ameren Missouri		Ameren Illinois
Circuit miles of electric transmission lines^(a)	2,956		4,506
Circuit miles of electric distribution lines	32,967		45,746
Circuit miles of electric distribution lines underground	23	%	15	%
Miles of natural gas transmission and distribution mains	3,282		18,137
Propane-air plants	1		—
Underground gas storage fields	—		12
Billion cubic feet of total working capacity of underground gas storage fields	—		24

Ÿ(a) AATXI ~~portion~~and ofEEI ~~Ameren~~own ~~Missouri’s~~29 ~~Osage~~miles ~~energy~~and ~~center~~42 ~~reservoir,~~miles ~~certain facilities at Ameren Missouri’s Sioux energy center, most~~ of ~~Ameren Missouri’s Peno Creek and Audrain CT energy centers, certain substations, and most~~ transmission ~~and distribution~~ lines ~~and natural gas mains are situated on lands occupied under leases~~, ~~easements~~respectively, ~~franchises,~~not ~~licenses,~~reflected ~~or permits. The United States or the state of Missouri may own or may have paramount rights to certain lands lying~~ in ~~the~~this ~~bed of the Osage River or located between the inner and outer harbor lines of the Mississippi River on which certain of Ameren Missouri’s energy centers and other properties are located~~table.

ŸOur ~~The~~other ~~United~~properties ~~States,~~include ~~the~~office ~~state of Illinois~~buildings, ~~the state of Iowa~~warehouses, ~~or the city of Keokuk~~garages, ~~Iowa,~~and ~~may~~repair ~~own or may have paramount rights with respect to certain lands lying in the bed of the Mississippi River on which a portion of Ameren Missouri’s Keokuk energy center is located~~shops.

~~Substantially~~With only a few exceptions, we have fee title to all ofprincipal ~~the~~energy ~~properties~~centers and ~~plant~~other units of ~~Ameren~~property ~~Missouri~~material ~~and~~to ~~Ameren~~the ~~Illinois~~operation ~~are~~of ~~subject~~our businesses, and to the ~~first~~real ~~liens~~property ofon ~~the~~which ~~indentures~~such facilities are located (subject to mortgage liens securing ~~their~~our outstanding first mortgage bonds and to certain permitted liens and judgment liens). The exceptions are as follows:

• A portion of Ameren Missouri’s ~~has~~Osage ~~conveyed~~energy ~~most~~center ofreservoir, ~~its~~certain ~~Peno~~facilities ~~Creek~~at CTAmeren Missouri’s Sioux energy center, tomost ~~the~~of ~~city~~Ameren ofMissouri’s ~~Bowling~~Peno ~~Green~~Creek and Audrain CT energy centers, ~~Missouri~~certain substations, and ~~leased~~most ~~the~~transmission ~~energy~~and ~~center~~distribution ~~back from~~lines ~~the~~and ~~city~~natural ~~through~~gas ~~2022.~~mains ~~Under~~are ~~the~~situated ~~terms~~on oflands ~~this~~occupied ~~capital~~under ~~lease~~leases, ~~Ameren~~easements, ~~Missouri~~franchises, islicenses, ~~responsible~~or ~~for~~permits. ~~all~~The ~~operation~~United ~~and~~States ~~maintenance~~or ~~for~~ the ~~energy~~state ~~center.~~of ~~Ownership~~Missouri ofmay ~~the~~own ~~energy~~or ~~center~~may ~~will~~have ~~transfer~~paramount rights to ~~Ameren~~certain ~~Missouri~~lands atlying in the ~~expiration~~bed of the ~~lease,~~ atOsage ~~which~~River ~~time~~or located between the ~~property~~inner and ~~plant~~outer ~~will~~harbor ~~become~~lines ~~subject~~of to the ~~lien~~Mississippi ofRiver ~~any~~on ~~outstanding~~which certain of Ameren Missouri’s ~~first~~energy ~~mortgage~~centers ~~bond~~and ~~indenture~~other properties are located.

~~Ameren~~• ~~Missouri~~The ~~operates~~United aStates, CTthe ~~energy~~state ~~center~~of ~~located in Audrain County~~Illinois, ~~Missouri.~~the ~~Ameren~~state ~~Missouri has rights and obligations as lessee~~ of ~~the CT energy center under a long-term lease with Audrain County. The lease term will expire on December 1~~Iowa, ~~2023.~~or ~~Under~~ the ~~terms~~city of ~~this~~Keokuk, ~~capital lease~~Iowa, ~~Ameren~~may ~~Missouri~~own isor ~~responsible~~may ~~for~~have ~~all~~paramount ~~operation and~~rights ~~maintenance~~with ~~for~~respect ~~the~~to ~~energy~~certain ~~center.~~lands ~~Ownership~~lying ofin the ~~energy~~bed ~~center will transfer to Ameren Missouri at the expiration~~ of the ~~lease,~~Mississippi atRiver on which ~~time~~a ~~the~~portion ~~property and plant will become subject to the lien~~ of ~~any outstanding~~ Ameren Missouri’s ~~first mortgage~~Keokuk ~~bond~~energy ~~indenture.~~center is located.

~~ITEM~~Substantially 3.all ~~LEGAL~~of ~~PROCEEDINGS~~the properties and plant of Ameren Missouri and Ameren Illinois are subject to the first liens of the indentures securing their mortgage bonds.

WeAmeren ~~are~~Missouri ~~involved~~has ~~in legal~~conveyed ~~and~~most ~~administrative~~of ~~proceedings~~its ~~before~~Peno ~~various~~Creek ~~courts~~CT ~~and~~energy ~~agencies~~center ~~with respect~~ to ~~matters~~the ~~that~~city ~~arise~~of inBowling ~~the~~Green, ~~ordinary~~Missouri, ~~course~~and ofleased ~~business,~~the ~~some~~energy ofcenter ~~which~~back ~~involve~~from ~~substantial~~the ~~amounts~~city ofthrough ~~money~~2022. WeUnder ~~believe that~~ the ~~final~~terms ~~disposition~~ of ~~these proceedings, except as otherwise disclosed in~~ this ~~report,~~capital ~~will not have a material adverse effect on our results of operations~~lease, ~~financial~~Ameren ~~position,~~Missouri ~~or liquidity. Risk of loss~~ is ~~mitigated,~~responsible infor ~~some~~all ~~cases,~~operation byand ~~insurance~~maintenance orfor ~~contractual~~the orenergy ~~statutory indemnification~~center. WeOwnership ~~believe~~of ~~that~~the weenergy ~~have~~center ~~established~~will ~~appropriate~~transfer ~~reserves~~to ~~for~~Ameren ~~potential~~Missouri ~~losses.~~at ~~Material~~the ~~legal~~expiration ~~and~~of ~~administrative~~the ~~proceedings~~lease, at which ~~are~~time ~~discussed~~the inproperty ~~Note 2 – Rate~~ and ~~Regulatory~~plant ~~Matters,~~will ~~and~~become ~~Note~~subject 15to –the ~~Commitment~~lien ~~and Contingencies under Part II, Item 8,~~ of ~~this~~any ~~report~~outstanding ~~and~~Ameren ~~incorporated~~Missouri ~~herein~~first bymortgage ~~reference,~~bond ~~include the following:~~ indenture.

ŸAmeren ~~appeals~~Missouri operates a CT energy center located in Audrain County, Missouri. Ameren Missouri has rights and obligations as lessee of the ~~MoPSC’s~~CT ~~2010~~energy center under a long-term lease with Audrain County. The lease will expire on December 1, 2023. Under the terms of this capital lease, Ameren Missouri is responsible for all operation and ~~2011~~maintenance ~~electric~~for ~~rate~~the ~~orders;~~energy center. Ownership of the energy center will transfer to Ameren Missouri at the expiration of the lease, at which time the property and plant will become subject to the lien of any outstanding Ameren Missouri first mortgage bond indenture.

ŸITEM ~~appeal~~3. ofLEGAL ~~the MoPSC’s April 2011 FAC prudence review order and completion of the current FAC prudence review;~~PROCEEDINGS

ŸWe ~~electric~~are ~~rate~~involved ~~proceedings~~in ~~for~~legal ~~Ameren~~and ~~Missouri~~administrative ~~pending~~proceedings before ~~the~~various ~~MoPSC~~courts and agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in this report, will not have a material adverse effect on our results of operations, financial position, or liquidity. Risk of loss is mitigated, in some cases, by insurance or contractual or statutory indemnification. We believe that we have established appropriate reserves for ~~Ameren~~potential ~~Illinois~~losses. ~~pending~~Material ~~before~~legal and administrative proceedings, which are discussed in Note 2 - Rate and Regulatory Matters and Note 15 - Commitment and Contingencies under Part II, Item 8, of this report and incorporated herein by reference, include the ~~ICC;~~following:

Ÿ• ~~FERC~~appeal ~~litigation~~of tothe ~~determine~~MoPSC's ~~wholesale~~April ~~distribution~~2011 ~~revenues~~FAC ~~for~~prudence ~~seven~~review order and completion of ~~Ameren~~the ~~Illinois’~~current ~~wholesale~~FAC ~~customers~~prudence review;

Ÿ• Ameren Missouri’'s appeal toof ~~FERC~~the toMoPSC's ~~contest~~December ~~additional~~2012 ~~charges~~electric ~~under~~rate ~~a power purchase agreement with Entergy Arkansas, Inc.~~order;

Ÿ• ~~the~~Ameren ~~EPA’s~~Illinois' ~~Clean~~appeal ~~Air~~of ~~Act-related~~the ~~litigation~~ICC's ~~filed~~2012 ~~against~~electric ~~Ameren~~distribution ~~Missouri~~rate ~~and~~orders ~~NSR~~in ~~investigations~~its atinitial ~~Genco~~ and ~~AERG~~update IEIMA filings;

Ÿ• ~~remediation~~natural ~~matters~~gas ~~associated~~rate ~~with~~proceeding ~~MGP~~for ~~and~~Ameren ~~waste~~Illinois ~~disposal~~pending ~~sites~~before of the ~~Ameren Companies~~ICC;

Ÿ• FERC litigation ~~associated~~to ~~with~~determine ~~the~~wholesale ~~breach~~distribution ofrevenues ~~the~~for ~~upper~~five ~~reservoir~~of at Ameren ~~Missouri’s~~Illinois' ~~Taum~~wholesale ~~Sauk pumped-storage hydroelectric energy center~~customers;

Ÿ• ~~litigation~~Entergy's ~~alleging~~rehearing ~~that~~request ~~CO2~~of ~~emissions~~a ~~from~~FERC ~~several~~May ~~industrial~~2012 ~~companies,~~order ~~including~~requiring Entergy to refund to Ameren Missouri ~~and~~additional ~~Genco,~~charges ~~created~~Ameren ~~the~~Missouri ~~atmospheric~~paid ~~conditions~~under ~~that~~an ~~intensified~~expired ~~Hurricane~~power ~~Katrina~~purchase agreement;

Ÿ• ~~asbestos-related~~Ameren ~~litigation~~Illinois' ~~associated~~request ~~with~~for ~~Ameren,~~rehearing ~~Ameren~~of ~~Missouri,~~a FERC July 2012 order regarding the inclusion of acquisition premiums in Ameren Illinois' ~~and~~transmission ~~Genco~~rates; ~~and~~

Ÿ• ~~Genco’~~ATXI's ~~challenge~~request ~~before~~for ~~the~~a ~~Informal~~certificate ~~Conference~~of ~~Board~~public ofconvenience ~~the~~and ~~Illinois~~necessity ~~Department~~and ofproject ~~Revenue~~approval ~~regarding~~from the ~~State’s~~ICC ~~position that EEI did not qualify~~ for ~~manufacturing~~the ~~tax~~Illinois ~~exemptions~~Rivers ~~for 2010 transactions.~~project;

26• the EPA's Clean Air Act-related litigation filed against Ameren Missouri, NSR investigations at Genco and AERG, and the Notice of Violation for alleged permitting violations at Genco;

~~Table~~• remediation matters associated with former MGP and waste disposal sites of ~~Contents~~the Ameren Companies;

~~ITEM~~• 4.litigation ~~MINE~~associated ~~SAFETY~~with ~~DISCLOSURES.~~the breach of the upper reservoir at Ameren Missouri's Taum Sauk pumped-storage hydroelectric energy center;

~~Not~~• ~~applicable.~~ litigation alleging that the CO2 emissions from several industrial companies, including Ameren Missouri, Genco,

~~EXECUTIVE OFFICERS OF THE REGISTRANTS (ITEM 401(b) OF REGULATION S-K):~~ 28

~~The~~Table ~~executive officers~~ of the Ameren Companies, including major subsidiaries, are listed below, along with their ages as of December 31, 2011, all positions and offices held with the Ameren Companies as of December 31, 2011, (except as otherwise noted below), tenure as officer, and business background for at least the last five years. Some executive officers hold multiple positions within the Ameren Companies; their titles are given in the description of their business experience. Contents

~~AMEREN~~and ~~CORPORATION:~~AERG, created atmospheric conditions that intensified Hurricane Katrina;

Name	Age	Positions and Offices Held
Thomas R. Voss	64	Chairman, President and Chief Executive Officer, and Director
Voss joined Ameren Missouri in 1969. He was elected senior vice president of Ameren Missouri, CIPS, and Ameren Services in 1999, of Genco in 2001, of CILCO in 2003, and of IP in 2004. In 2003, Voss was elected president of Genco; he relinquished his presidency of this company in 2004. In 2006, he was elected executive vice president of Ameren Missouri, CIPS, CILCO and IP. In 2007, Voss was elected chairman, president, and chief executive officer of Ameren Missouri. He relinquished his positions at CIPS, CILCO and IP in 2007. In 2009, Voss was elected president and chief executive officer of Ameren; at that time, he relinquished his other positions. In 2010, the Ameren board of directors elected Voss to the position of chairman of the board. He has been a member of the Ameren board since 2009.
Martin J. Lyons, Jr.	45	Senior Vice President and Chief Financial Officer
Lyons joined Ameren, Ameren Missouri, CIPS, Genco, and Ameren Services in 2001 as controller. He was elected controller of CILCO in 2003. He was also elected vice president of Ameren, Ameren Missouri, CIPS, Genco, CILCO, and Ameren Services in 2003 and vice president and controller of IP in 2004. In 2007, his positions at Ameren Missouri were changed to vice president and principal accounting officer. In 2008, Lyons was elected senior vice president and principal accounting officer of the Ameren Companies. In 2009, Lyons was also elected chief financial officer of the Ameren Companies. With the Ameren Illinois Merger in 2010, Lyons remained senior vice president, chief financial officer and principal accounting officer at Ameren Illinois.
Gregory L. Nelson	54	Senior Vice President, General Counsel and Secretary
Nelson joined Ameren Missouri in 1995 as a manager in the tax department and assumed a similar position with Ameren Services in 1998. Nelson was elected vice president and tax counsel of Ameren Services in 1999 and vice president of Ameren Missouri, CIPS, CILCO and Genco in 2003 and of IP in 2004. In 2010, Nelson was elected vice president, tax and deputy general counsel of Ameren Services. He remained vice president of Ameren Missouri, CIPS, CILCO, IP and Genco. With the Ameren Illinois Merger in 2010, Nelson remained vice president at Ameren Illinois. Effective March 2, 2011, Nelson was elected to the positions of senior vice president and general counsel of Ameren, Ameren Missouri, Ameren Illinois, Genco and Ameren Services. Effective May 1, 2011, Nelson was elected to the position of secretary.
Jerre E. Birdsong	57	Vice President and Treasurer
Birdsong joined Ameren Missouri in 1977 and was elected treasurer of Ameren Missouri in 1993. He was elected treasurer of Ameren, CIPS, and Ameren Services in 1997 and of Genco in 2000. In addition to being treasurer, in 2001 he was elected vice president at Ameren, Ameren Missouri, CIPS, Ameren Services and Genco. Additionally, he was elected vice president and treasurer of CILCO in 2003 and of IP in 2004. With the Ameren Illinois Merger in 2010, Birdsong, remained vice president and treasurer at Ameren Illinois.


•	Ameren Illinois' receipt of tax liability notices relating to prior-period electric and natural gas municipal taxes;

27• asbestos-related litigation associated with Ameren, Ameren Missouri, and Ameren Illinois; and

~~Table~~• ofMerchant ~~Contents~~Generation's challenge before the Informal

~~SUBSIDIARIES:~~Conference Board of the Illinois Department of Revenue regarding the State's position that EEI did not qualify for manufacturing tax exemptions for 2010 transactions.

Name	Age	Positions and Offices Held
Warner L. Baxter	50	Chairman, President and Chief Executive Officer (Ameren Missouri)
Baxter joined Ameren Missouri in 1995. He was elected senior vice president, finance, of Ameren, Ameren Missouri, CIPS, Ameren Services, and Genco in 2001 and of CILCO in 2003. Baxter was elected to the positions of executive vice president and chief financial officer of Ameren, Ameren Missouri, CIPS, Genco, CILCO and Ameren Services in 2003 and of IP in 2004. He was elected chairman, president, chief executive officer and chief financial officer of Ameren Services in 2007. In 2009, Baxter was elected chairman, president and chief executive officer of Ameren Missouri; at that time, he relinquished his other positions.
Maureen A. Borkowski	54	Chairman, President and Chief Executive Officer (ATX)
Borkowski joined Ameren Missouri in 1981. She left the company in 2000 before rejoining Ameren in 2005. Borkowski has led Ameren’s transmission operations since 2005 as vice president, transmission, of Ameren Services. In 2010, Borkowski was elected president and chief executive officer of ATX. Effective March 2, 2011, Borkowski was elected chairman of ATX. Effective April 26, 2011, she was also elected senior vice president, transmission, of Ameren Services.
Scott A. Cisel	58	Chairman, President and Chief Executive Officer (Ameren Illinois)
Cisel joined CILCO in 1975. He was named senior vice president and leader of CILCO’s Sales and Marketing Business Unit in 2001. Cisel assumed the positions of vice president and chief operating officer of CILCO in 2003, upon Ameren’s acquisition of that company. In 2004, Cisel was elected vice president of Ameren Missouri and president and chief operating officer of CIPS, CILCO and IP. In 2007, Cisel was elected chairman and chief executive officer of CIPS, CILCO and IP, in addition to his position as president. He relinquished his position at Ameren Missouri in 2007. With the Ameren Illinois Merger in 2010, Cisel remained chairman, president and chief executive officer at Ameren Illinois.
Daniel F. Cole	58	Chairman, President and Chief Executive Officer (Ameren Services)
Cole joined Ameren Missouri in 1976. He was elected senior vice president of Ameren Missouri and Ameren Services in 1999 and of CIPS in 2001. He was elected president of Genco in 2001; he relinquished that position in 2003. He was elected senior vice president of CILCO in 2003 and of IP in 2004. In 2009, Cole was elected chairman, president and chief executive officer of Ameren Services and remained senior vice president of Ameren Missouri, CIPS, CILCO and IP. With the Ameren Illinois Merger in 2010, Cole remained senior vice president at Ameren Illinois.
Adam C. Heflin	47	Senior Vice President and Chief Nuclear Officer (Ameren Missouri)
Heflin joined Ameren Missouri in 2005 as vice president of nuclear operations and was elected senior vice president and chief nuclear officer of Ameren Missouri in 2008.
Richard J. Mark	56	Senior Vice President (Ameren Missouri)
Mark joined Ameren Services in 2002 as vice president of customer service. In 2003, he was elected vice president of governmental policy and consumer affairs at Ameren Services, with responsibility for government affairs, economic development and community relations for Ameren’s operating utility companies. He was elected senior vice president, customer operations of Ameren Missouri in 2005, with responsibility for Missouri energy delivery. In 2007, Mark relinquished his position at Ameren Services.
Michael L. Moehn	42	Senior Vice President (Ameren Illinois) (Effective January 1, 2012)
Moehn joined Ameren Services in 2000. He was named director of Ameren Services’ corporate modeling and transaction support in 2001 and elected vice president of business services for AER in 2002. In 2004, Moehn was elected vice president of corporate planning of Ameren Services and relinquished his position at AER. In 2008, he was elected senior vice president, corporate planning and business risk management of Ameren Services. Effective January 1, 2012, Moehn relinquished his position at Ameren Services and was elected senior vice president of customer operations of Ameren Illinois.
Charles D. Naslund	59	Senior Vice President (Ameren Missouri)
Naslund joined Ameren Missouri in 1974. He was elected vice president of power operations at Ameren Missouri in 1999, vice president of Ameren Services in 2000 and vice president of nuclear operations at Ameren Missouri in 2004. He relinquished his position at Ameren Services in 2001. Naslund was elected senior vice president and chief nuclear officer at Ameren Missouri in 2005. In 2008, he was elected chairman, president and chief executive officer of AER and chairman and president of Genco. Naslund relinquished his positions at Ameren Missouri in 2008. Effective March 2, 2011, Naslund assumed the position of senior vice president, generation and environmental projects of Ameren Missouri and relinquished his positions of chairman, president and chief executive officer of AER and chairman and president of Genco.


ITEM 4.	MINE SAFETY DISCLOSURES

28Not applicable.

~~Table~~EXECUTIVE ofOFFICERS ~~Contents~~OF THE REGISTRANTS (ITEM 401(b) OF REGULATION S-K):

Name	Age	Positions and Offices Held
Steven R. Sullivan	51	Chairman, President and Chief Executive Officer (AER); Chairman and President (Genco); and President and Chief Executive Officer (Marketing Company)
Sullivan joined Ameren, Ameren Missouri, CIPS and Ameren Services in 1998 as vice president, general counsel and secretary. He added those positions at Genco in 2000. In 2003, Sullivan was elected vice president, general counsel and secretary of CILCO. He was elected senior vice president, general counsel and secretary of Ameren, Ameren Missouri, CIPS, Genco, CILCO and Ameren Services in 2003 and of IP in 2004. With the Ameren Illinois Merger in 2010, Sullivan remained senior vice president, general counsel and secretary at Ameren Illinois. Effective March 2, 2011, Sullivan was elected to the positions of chairman, president and chief executive officer of AER and chairman and president of Genco and relinquished his positions of senior vice president and general counsel of Ameren, Ameren Missouri, Ameren Illinois, Genco and Ameren Services. Effective May 1, 2011, Sullivan relinquished his position as secretary for the Ameren Companies. Effective October 31, 2011, Sullivan was elected to the positions of president and chief executive officer of Marketing Company.

The executive officers of the Ameren Companies, including major subsidiaries, are listed below, along with their ages as of December 31, 2012, all positions and offices held with the Ameren Companies as of December 31, 2012 (except as otherwise noted below), tenure as officer, and business background for at least the last five years. Some executive officers hold multiple positions within the Ameren Companies; their titles are given in the description of their business experience.

~~Officers~~AMEREN are generally elected or appointed annually by the respective board of directors of each company, following the election of board members at the annual meetings of shareholders. No special arrangement or understanding exists between any of the above-named executive officers and the Ameren Companies nor, to our knowledge, with any other person or persons pursuant to which any executive officer was selected as an officer. There are no family relationships among the officers. All of the above-named executive officers have been employed by an Ameren company for more than five years in executive or management positions. CORPORATION:

PART II



Name	Age	Positions and Offices Held
Thomas R. Voss	65	Chairman, President and Chief Executive Officer, and Director
Voss joined Ameren Missouri in 1969. He was elected senior vice president of Ameren Missouri, CIPS, and Ameren Services in 1999, of CILCO in 2003, and of IP in 2004. In 2003, Voss was elected president of Genco; he relinquished his presidency of this company in 2004. In 2006, he was elected executive vice president of Ameren Missouri, CIPS, CILCO and IP. In 2007, Voss was elected chairman, president and chief executive officer of Ameren Missouri, and relinquished his positions at CIPS, CILCO and IP in 2007. In 2009, Voss was elected president and chief executive officer of Ameren; at that time, he relinquished his other positions. In 2010, the Ameren board of directors elected Voss to the additional position of chairman of the board. He has been a member of the Ameren board since 2009.

Martin J. Lyons, Jr.	46	Executive Vice President (Effective January 1, 2013) and Chief Financial Officer
Lyons joined Ameren, Ameren Missouri, CIPS, and Ameren Services in 2001 as controller. He was elected controller of CILCO in 2003. He was also elected vice president of Ameren, Ameren Missouri, CIPS, CILCO, and Ameren Services in 2003 and vice president and controller of IP in 2004. In 2007, his positions at Ameren Missouri were changed to vice president and principal accounting officer. In 2008, Lyons was elected senior vice president and principal accounting officer of the Ameren companies. In 2009, Lyons was also elected chief financial officer of the Ameren companies. Following the Ameren Illinois Merger in 2010, Lyons remained senior vice president, chief financial officer and principal accounting officer of Ameren Illinois. Effective January 1, 2013, Lyons was elected executive vice president and chief financial officer of the Ameren companies, and relinquished his duties as principal accounting officer.

Gregory L. Nelson	55	Senior Vice President, General Counsel and Secretary
Nelson joined Ameren Missouri in 1995 as a manager in the tax department and assumed a similar position with Ameren Services in 1998. Nelson was elected vice president and tax counsel of Ameren Services in 1999 and vice president of Ameren Missouri, CIPS, and CILCO in 2003 and of IP in 2004. In 2010, Nelson was elected vice president, tax and deputy general counsel of Ameren Services. He remained vice president of Ameren Missouri, CIPS, CILCO, and IP. Following the Ameren Illinois Merger in 2010, Nelson remained vice president at Ameren Illinois. In 2011, Nelson was elected to the positions of senior vice president, general counsel and secretary of the Ameren companies.

Bruce A. Steinke	51	Senior Vice President, Finance and Chief Accounting Officer (Effective January 1, 2013)
Steinke joined Ameren Services in 2002 as a manager in the controller's department and head of investor relations. In 2008, he was elected vice president and controller of Ameren, CIPS, CILCO, IP and Ameren Services. In 2009, Steinke relinquished his positions at CIPS, CILCO and IP. Effective January 1, 2013, Steinke was elected senior vice president, finance and chief accounting officer of the Ameren companies.

Jerre E. Birdsong	58	Vice President and Treasurer
Birdsong joined Ameren Missouri in 1977 and was elected treasurer of Ameren Missouri in 1993. He was elected treasurer of Ameren, CIPS and Ameren Services in 1997. In addition to being treasurer, in 2001, Birdsong was elected vice president at Ameren, Ameren Missouri, CIPS, and Ameren Services. Additionally, he was elected vice president and treasurer of CILCO in 2003 and of IP in 2004. Following the Ameren Illinois Merger in 2010, Birdsong, remained vice president and treasurer at Ameren Illinois. Effective February 1, 2013, Birdsong retired from the Ameren companies.

~~ITEM 5. MARKET FOR REGISTRANTS’ COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES.~~29

~~Ameren’s~~Table ~~common stock is listed on the NYSE (ticker symbol: AEE). Ameren common shareholders~~ of ~~record totaled 63,531 on January 31, 2012. The following table presents the price ranges, closing prices, and dividends declared per Ameren common share for each quarter during 2011 and 2010.~~ Contents

	High		Low		Close		Dividends Declared
AEE 2011 Quarter Ended:
March 31	$	29.14	$	26.46	$	28.07		38	1/2¢
June 30		30.14		27.78		28.84		38	1/2
September 30		31.44		25.55		29.77		38	1/2
December 31		34.11		27.98		33.13		40
AEE 2010 Quarter Ended:
March 31	$	28.27	$	24.14	$	26.08		38	1/2¢
June 30		26.92		23.09		23.77		38	1/2
September 30		28.99		23.45		28.40		38	1/2
December 31		29.89		27.65		28.19		38	1/2

SUBSIDIARIES:

There is no trading market for the common stock of Ameren Missouri, Ameren Illinois and Genco. Ameren holds all outstanding common stock of Ameren Missouri and Ameren Illinois; AER holds all outstanding common stock of Genco.



Name	Age	Positions and Offices Held
Warner L. Baxter	51	Chairman, President and Chief Executive Officer (Ameren Missouri)
Baxter joined Ameren Missouri in 1995 as assistant controller. He was elected senior vice president, finance, of Ameren, Ameren Missouri, CIPS, and Ameren Services in 2001 and of CILCO in 2003. Baxter was elected to the positions of executive vice president and chief financial officer of Ameren, Ameren Missouri, CIPS, CILCO and Ameren Services in 2003 and of IP in 2004. He was elected chairman, president, chief executive officer and chief financial officer of Ameren Services in 2007. In 2009, Baxter was elected chairman, president and chief executive officer of Ameren Missouri; at that time, he relinquished his other positions.

Maureen A. Borkowski	55	Chairman, President and Chief Executive Officer (ATXI)
Borkowski joined Ameren Missouri in 1981. She left the company in 2000 before rejoining Ameren in 2005 as vice president, transmission, of Ameren Services. In 2011, Borkowski was elected chairman, president and chief executive officer of ATXI. In 2011, she was also elected senior vice president, transmission, of Ameren Services.

Daniel F. Cole	59	Chairman, President and Chief Executive Officer (Ameren Services)
Cole joined Ameren Missouri in 1976. He was elected senior vice president of Ameren Missouri and Ameren Services in 1999 and of CIPS in 2001. He was elected senior vice president of CILCO in 2003 and of IP in 2004. In 2009, Cole was elected chairman, president and chief executive officer of Ameren Services and remained senior vice president of Ameren Missouri, CIPS, CILCO and IP. Following the Ameren Illinois Merger in 2010, Cole remained senior vice president at Ameren Illinois.

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