UNITED STATES ~~SECURITIES~~ ~~AND EXCHANGE COMMISSION~~

~~Washington,~~SECURITIES ~~D.C.~~AND ~~20549~~ EXCHANGE COMMISSION

Washington, DC 20549

FORM 8-K

CURRENT REPORT ~~Pursuant~~ ~~to Section 13 OR 15(d) of The Securities Exchange Act of 1934~~

~~For~~Pursuant ~~the~~to ~~quarterly~~Section 13 ~~period~~or ~~ended December 12,~~15(d) ~~2009~~ of the

~~Date~~Securities ofExchange ~~Report~~Act ~~(Date~~ of 1934 ~~earliest event reported): September 14, 2010~~

Date of Report (Date of Earliest Event Reported): December 7, 2011

ERP OPERATING LIMITED PARTNERSHIP

(Exact ~~name~~Name of ~~registrant~~Registrant as ~~specified~~Specified in its ~~charter~~Charter)

Illinois (State or other jurisdiction of incorporation) 0-24920 (Commission File Number) 36-3894853 (I.R.S. Employer Identification No.)


Illinois	0-24920	36-3894853
(State or other jurisdiction of incorporation or organization)	(Commission File Number)	(I.R.S. Employer Identification No.)

Two North Riverside Plaza Chicago, Illinois (Address of principal executive offices) 60606 (Zip Code)


Two North Riverside Plaza Suite 400, Chicago, Illinois		60606
(Address of principal executive offices)		(Zip Code)

Registrant’s telephone number, including area code: (312) 474-1300

Not applicable ~~(Former~~ ~~name or former address, if changed since last report)~~

~~Check~~(Former ~~the~~Name ~~appropriate~~or ~~box~~Former ~~below~~Address, if ~~the~~Changed ~~Form~~Since ~~8-K~~Last ~~filing~~Report) ~~is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:~~

oCheck ~~Written~~the ~~communications~~appropriate ~~pursuant~~box below if the Form 8-K filing is intended to ~~Rule~~simultaneously ~~425~~satisfy the filing obligation of the registrant under any of the ~~Securities~~following ~~Act~~provisions (17see ~~CFR~~General ~~230~~Instruction A.~~425~~2. below):

o¨ ~~Soliciting~~Written ~~material~~communications pursuant to Rule ~~14a-12~~425 under the ~~Exchange~~Securities Act (17 CFR ~~240~~230.~~14a-12~~425)

o¨ ~~Pre-commencement~~Soliciting ~~communications~~material pursuant to Rule ~~14d~~14a-~~2(b)~~12 under the Exchange Act (17 CFR 240.~~14d~~14a-~~2(b~~12))

o¨ Pre-commencement communications pursuant to Rule ~~13e~~14d-42(cb) under the Exchange Act (17 CFR 240.~~13e~~14d-42(cb))

~~ITEM~~¨ ~~8.01~~Pre-commencement ~~Other~~communications ~~Events~~pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

~~ERP~~Item 8.01. ~~Operating~~Other ~~Limited Partnership (the “Operating Partnership”) is re-issuing in an updated format its historical financial statements to satisfy SEC requirements as they relate to discontinued operations~~Events.

~~The~~On ~~results~~December 7, of2011, ~~operations~~ERP ~~of the~~ Operating Limited Partnership’s, ~~consolidated~~an ~~properties~~Illinois ~~that~~limited ~~were~~partnership (the “Company”), agreed to issue ~~sold~~$1,000,000,000 ~~during~~aggregate principal amount of 4.625% Notes due December 15, 2021 (the ~~first~~“Notes”) ~~six~~in ~~months~~a ofpublic ~~2010~~offering. ~~were~~The ~~reported~~Company asagreed to sell the Notes pursuant to a ~~component~~Terms Agreement, dated as of ~~discontinued~~December 7, ~~operations~~2011, among the ~~for~~Company and each ~~period~~of ~~presented~~Morgan ~~(including~~Stanley & ~~the~~Co. ~~comparable~~LLC, ~~period~~Merrill Lynch, Pierce, Fenner & Smith Incorporated and Barclays Capital Inc., as representatives of the ~~prior~~underwriters ~~year)~~named intherein. ~~the~~The ~~Operating Partnership’s~~Notes ~~second~~will ~~quarter~~be ~~2010~~issued ~~quarterly~~pursuant ~~report~~to onan ~~Form~~Indenture, dated ~~10-Q~~as ~~filed~~of ~~with~~October 1, 1994, between the ~~SEC~~Company onand ~~August 5~~The Bank of New York Mellon Trust Company, ~~2010~~ N.A. ~~Under~~(formerly ~~SEC~~known ~~requirements,~~as ~~the~~The ~~same~~Bank ~~reclassification~~of New York Trust Company, N.A.) (as ~~discontinued~~successor ~~operations~~to isJ.P. ~~required~~Morgan ~~for~~Trust Company, National Association, as successor to ~~previously~~Bank ~~issued~~One ~~annual~~Trust ~~financial~~Company, ~~statements~~N.A., ~~for~~successor ~~each~~to The First National Bank of Chicago) (the ~~three~~“Trustee”), ~~years~~as ~~shown~~supplemented inby the ~~Operating Partnership’s~~First ~~most~~Supplemental ~~recent~~Indenture, ~~annual~~dated ~~report~~as onof ~~Form~~September 9, ~~10-K~~2004, ifby ~~those~~and ~~financial~~between ~~statements~~the ~~are~~Company and the Trustee, as further ~~incorporated~~supplemented by ~~reference~~that incertain ~~subsequent~~Second ~~filings~~Supplemental ~~with~~Indenture, ~~the~~dated ~~SEC~~as ~~made~~of ~~under~~August 23, 2006, by and between the ~~Securities~~Company ~~Act~~and the Trustee, as further supplemented by that certain Third Supplemental Indenture, dated as of ~~1933~~June 4, 2007, by and asbetween ~~amended~~the Company and the Trustee, ~~even~~and ~~though~~as ~~those~~further ~~financial~~supplemented ~~statements~~by ~~relate~~that tocertain ~~periods~~Fourth ~~prior~~Supplemental Indenture, to be dated as of December 12, 2011, by and between the ~~sale~~Company ~~date~~and the Trustee.

~~The~~Item 9.01. ~~aforementioned~~Financial ~~reclassification~~Statements ~~has~~and ~~no effect on the Operating Partnership’s previously reported net income, net income available to Units, funds from operations (“FFO”) or FFO available to Units~~Exhibits.

This report on Form 8-K updates Items 6, 7, 8 and 15 (Exhibit 12 only) of the Operating Partnership’s annual report on Form 10-K for the year ended December 31, 2009 to reclassify those properties sold during the first six months of 2010 as a component of discontinued operations for each period presented in the annual report. Exhibit 12 also reflects certain interim information for the six months ended June 30, 2010 and 2009, respectively. All other items of the Operating Partnership’s Form 10-K remain unchanged. No attempt has been made to update matters in the Form 10-K except to the extent expressly provided above.


Exhibit Number		Description

1.1		Terms Agreement dated December 7, 2011, among ERP Operating Limited Partnership and each of Morgan Stanley & Co. LLC, Merrill Lynch, Pierce, Fenner & Smith Incorporated and Barclays Capital Inc.

1.2		Standard Underwriting Provisions dated December 7, 2011.

4.1		Form of 4.625% Note due December 15, 2021.

4.2		Form of Fourth Supplemental Indenture.

5.1		Opinion of DLA Piper LLP (US).

23.1		Consent of DLA Piper LLP (US) (included in Exhibit 5.1).

ITEM 9.01 Financial Statements and Exhibits

Exhibit
Number		Exhibit
12		Computation of Ratio of Earnings to Combined Fixed Charges
23.1		Consent of Independent Registered Public Accounting Firm
99.1		Form 10-K, Item 6. Selected Financial Data
		Form 10-K, Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations
		Form 10-K, Item 8. Financial Statements and Supplementary Data

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	~~ERP OPERATING LIMITED PARTNERSHIP~~		ERP OPERATING LIMITED PARTNERSHIP
	~~By:~~	~~EQUITY RESIDENTIAL~~	By:	EQUITY RESIDENTIAL, its general partner
		ITS GENERAL PARTNER
	Date: December 9, 2011			By:	/s/ MARK J. PARRELL
Date: September 14, 2010	By:	/s/ Mark J. Parrell
				Name:	Mark J. Parrell
	Name:	Mark J. Parrell
				Its:	Executive Vice President and Chief Financial Officer
	Its:	Executive Vice President and
	Date: December 9, 2011			By:	/s/ BRUCE C. STROHM
		Chief Financial Officer
				Name:	Bruce C. Strohm
Date: September 14, 2010	By:	/s/ Ian S. Kaufman
				Its:	Executive Vice President, General Counsel and Corporate Secretary
	Name:	Ian S. Kaufman
	Its:	Senior Vice President and
		Chief Accounting Officer

EXHIBIT INDEX

Exhibit
ExhibitNumber		Description
Number		Exhibit
1.1		Terms Agreement dated December 7, 2011, among ERP Operating Limited Partnership and each of Morgan Stanley & Co. LLC, Merrill Lynch, Pierce, Fenner & Smith Incorporated and Barclays Capital Inc.
12		Computation of Ratio of Earnings to Combined Fixed Charges
1.2		Standard Underwriting Provisions dated December 7, 2011.
23.1		Consent of Independent Registered Public Accounting Firm
4.1		Form of 4.625% Note due December 15, 2021.
99.1		Form 10-K, Item 6. Selected Financial Data
4.2		Form of Fourth Supplemental Indenture.
		Form 10-K, Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations
5.1		Opinion of DLA Piper LLP (US).
		Form 10-K, Item 8. Financial Statements and Supplementary Data
23.1		Consent of DLA Piper LLP (US) (included in Exhibit 5.1).

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