UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K Current Report Pursuant To Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 27, 2004 (Date of earliest event reported) Indymac MBS Inc (as Depositor under the Pooling and Servicing Agreement, dated as April 1, 2004, providing for the issuance of Residential Asset Securitization Trust Series 2004-A3 Mortgage Pass-Through Certificates, Series 2004-C) (Exact name of registrant as specified in charter) DELAWARE (State or Other Jurisdiction of Incorporation) 333-102888-20 95-4791925 (Commission File Number) (I.R.S. Employer Identification No.) 155 NORTH LAKE AVENUE PASADENA, CALIFORNIA 91101 (Address of principal executive offices) (Zip Code) Registrant's Telephone Number, Including Area Code: (800) 669-2300 (Former name or former address, if changed since last report.) Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below): [ ] Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) [ ] Soliciting material pursuant to Rule 14a-12(b) under the Exchange Act (17 CFR 240.14a-12(b)) [ ] Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) [ ] Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Item 8.01 Other Events Attached hereto is a copy of the Monthly Remittance Statements to the Certificateholders which was derived from the monthly information submitted by the Master Servicer of the Trust to the Trustee. Item 9.01 Financial Statements and Exhibits (c) Exhibits: Exhibit No. Description 99.1 Monthly Remittance Statement to the Certificateholders dated as of December 27, 2004. 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. Deutsche Bank National Trust Company, in its capacity as Trustee under the Pooling and Servicing Agreement on behalf of Indymac MBS Inc, Registrant Date: ~~Sep~~Dec 2728, 2004 By: /s/ Katherine M. Wannenmacher Katherine M. Wannenmacher Vice President EXHIBIT INDEX DOCUMENT 99.1 Monthly Remittance Statement to the Certificateholders dated as of December 27, 2004.

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

External Parties

Table of Contents

Page

Seller

1. Certificate Payment Report

IndyMac Bank

2. Collection Account Report

3. Credit Enhancement Report

4. Collateral Report

Certificate Insurer(s)

5. Delinquency Report

6. REO Report

7. Foreclosure Report

8. Prepayment Report

9. Prepayment Detail Report

10. Realized Loss Report

11. Realized Loss Detail Report

Servicer(s)

12. Triggers and Adj. Cert. Report

IndyMac Bank

13. Other Related Information

Underwriter(s)

Bear, Stearns & Co. Inc

Total Number of Pages

Dates

Contacts

Cut-Off Date:

April 01, 2004

Brent Hoyler

Close Date:

April 29, 2004

Administrator

First Distribution Date:

May 25, 2004

(714) 247-6322

Brent.Hoyler@db.com

Address:

1761 East St. Andrew Place, Santa Ana, CA 92705

Distribution Date:

~~September~~December 27, 2004

Factor Information:

(800) 735-7777

Record Date:

~~August~~November 3130, 2004

Main Phone Number:

(714) 247-6000

https://www.corporatetrust.db.com/invr

https://www.tss.db.com/invr

Page 1 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Certificate Payment Report

Current Period Distribution -

Prior

Current

Class

Original

Principal

Total

Realized

Deferred

Principal

Class

Type

Cur

Face Value

Balance

Interest

Principal

Distribution

Loss

Interest

Balance

(1)

(2)

(3)

(4)=(2)+(3)

(5)

(6)

(7)=(1)-(3)-(5)+(6)

A-1

PAC/SR

106,813,929.00

~~100~~96,~~855~~000,~~581~~993.6632

~~378~~360,~~208~~003.4372

1,~~821~~500,~~125~~250.5418

21,~~199~~860,~~333~~253.9790

0.00

9994,~~034~~500,~~456~~743.1214

A-2

PAC/SR

29,131,071.00

2726,~~506~~182,~~067~~088.2261

4555,~~041~~200.1957

~~496~~409,~~670~~159.5913

~~541~~464,~~711~~359.7870

0.00

2725,~~009~~772,~~396~~929.6348

A-3

INV/NTL

0.00

~~138~~119,~~332~~346.6069

0.00

~~138~~119,~~332~~346.6069

0.00

A-4

TAC/SR

73,048,000.00

7257,~~252~~779,~~175~~868.5509

~~316~~252,~~103~~786.2792

21,~~999~~749,~~470~~006.7794

32,~~315~~001,~~574~~793.0486

0.00

6956,~~252~~030,~~704~~861.7815

A-5

5,753,000.00

~~2,657,177~~0.8700

~~11,625~~0.1500

~~745,227~~0.0200

~~756,852~~0.1700

0.00

~~1,911,950~~0.8500

A-6

3,000,000.00

13,125.00

0.00

13,125.00

0.00

3,000,000.00

A-7

25,512,000.00

111,615.00

0.00

111,615.00

0.00

25,512,000.00

PO,RSTP

385,093.00

~~382~~328,~~762~~169.2619

0.00

~~25,125~~553.0005

0.00

~~357~~327,~~637~~616.2614

A-X

SR/NTL

0.00

9275,~~467~~424.1080

0.00

9275,~~467~~424.1080

0.00

A-R

SR/RES

100.00

0.00

B-1

SUB

6,122,000.00

65,~~096~~715,~~991~~170.5995

2625,~~674~~003.3487

5319,~~810~~170.4210

8044,~~484~~173.7697

0.00

65,~~043~~696,~~181~~000.1785

B-2

SUB

1,786,000.00

1,~~778~~667,~~704~~313.1884

7,~~781~~294.8350

155,~~698~~592.3758

2312,~~480~~887.2008

0.00

1,~~763~~661,~~005~~721.8126

B-3

SUB

1,276,000.00

1,~~270~~191,~~787~~205.5218

5,~~559~~211.7052

113,~~215~~995.6360

169,~~775~~207.3312

0.00

1,~~259~~187,~~571~~209.8958

B-4

SUB/NOF

893,000.00

~~889~~833,~~352~~656.0891

3,~~890~~647.9225

72,~~849~~796.1829

116,~~740~~443.1054

0.00

~~881~~830,~~502~~860.9062

B-5

SUB/NOF

383,000.00

~~381~~357,~~435~~548.4426

1,~~668~~564.7827

31,~~366~~199.4531

52,~~035~~763.2358

0.00

~~378~~356,~~068~~348.9995

B-6

SUB/NOF

1,020,571.00

1952,~~016,401~~750.9941

4,~~446~~168.7628

83,~~970~~195.4976

137,~~417~~364.2504

0.00

1949,~~007,431~~554.5065

NOF

100.00

~~4,766~~0.7200

0.00

~~4,766~~0.7200

0.00

100.00

Total

255,123,864.00

~~243~~219,~~599~~520,~~537~~864.3676

1,~~161~~034,~~306~~392.7939

63,~~188~~694,~~529~~918.4694

74,~~349~~729,~~836~~311.2533

0.00

~~237~~215,~~411~~825,~~007~~945.9082

Interest Accrual Detail Current Period Factor Information per $1,0000 of Original Face-

Interest Accrual Detail Current Period Factor Information per $1,000 of Original Face-

Orig. Principal

Prior

Current

Period

(with Notional)

Principal

Total

Principal

Class

Starting

Ending

Method

Cusip

Balance

Interest

Principal

Distribution

Balance

(1)

(2)

(3)

(4)=(2)+(3)

(5)

A-1

0811/01/04

0811/30/04

F-30/360

45660NE92

106,813,929.00

~~944~~898.~~217506~~768487

3.~~540816~~370382

1714.~~049514~~045455

2017.~~590329~~415836

~~927~~884.~~167992~~723032

A-2

0811/25/04

0912/24/04

A-30/360

45660NF26

29,131,071.00

~~944~~898.~~217506~~768487

1.~~546156~~894904

1714.~~049514~~045454

1815.~~595670~~940358

~~927~~884.~~167993~~723033

A-3

0811/25/04

0912/24/04

A-30/360

45660NF34

29,131,071.00

~~944~~898.~~217506~~768487

4.~~748627~~096886

0.000000

4.~~748627~~096886

~~927~~884.~~167993~~723033

A-4

0811/01/04

0811/30/04

F-30/360

45660NF42

73,048,000.00

~~989~~790.~~105459~~984943

43.~~327336~~460559

4123.~~061641~~943256

4527.~~388978~~403815

~~948~~767.~~043817~~041687

A-5

0811/01/04

0811/30/04

F-30/360

45660NF59

5,753,000.00

~~461~~0.~~876911~~000000

20.~~020711~~000000

~~129~~0.~~537115~~000000

~~131~~0.~~557825~~000000

~~332~~0.~~339797~~000000

A-6

0811/01/04

0811/30/04

F-30/360

45660NF67

3,000,000.00

1,000.000000

4.375000

0.000000

4.375000

1,000.000000

A-7

0811/01/04

0811/30/04

F-30/360

45660NF75

25,512,000.00

1,000.000000

4.375000

0.000000

4.375000

1,000.000000

0811/01/04

0811/30/04

F-30/360

45660NF83

385,093.00

~~993~~852.~~947592~~181655

0.000000

651.~~243980~~436147

~~928~~850.~~703612~~745508

A-X

0811/01/04

0811/30/04

F-30/360

45660NF91

235,616,408.78

~~951~~854.~~505491~~171871

0.~~392448~~320117

0.000000

0.~~392448~~320117

~~927~~838.~~453129~~598462

A-R

0811/01/04

0811/30/04

F-30/360

45660NG25

100.00

0.000000

B-1

0811/01/04

0811/30/04

F-30/360

45660NG33

6,122,000.00

~~995~~933.~~914993~~546382

4.~~357128~~084265

83.~~789680~~131346

137.~~146808~~215611

~~987~~930.~~125314~~415036

B-2

0811/01/04

0811/30/04

F-30/360

45660NG41

1,786,000.00

~~995~~933.~~914994~~546383

4.~~357128~~084267

83.~~789681~~131344

137.~~146809~~215610

~~987~~930.~~125314~~415039

B-3

0811/01/04

0811/30/04

F-30/360

45660NG58

1,276,000.00

~~995~~933.~~914984~~546379

4.~~357132~~084263

83.~~789679~~131348

137.~~146810~~215611

~~987~~930.~~125306~~415031

B-4

0811/01/04

0811/30/04

F-30/360

893,000.00

~~995~~933.~~914983~~546372

4.~~357133~~084267

83.~~789675~~131344

137.~~146809~~215610

~~987~~930.~~125308~~415028

B-5

0811/01/04

0811/30/04

F-30/360

383,000.00

~~995~~933.~~914987~~546371

4.~~357128~~084256

83.~~789687~~131358

137.~~146815~~215614

~~987~~930.~~125300~~415013

B-6

0811/01/04

0811/30/04

F-30/360

1,020,571.00

~~995~~933.~~915022~~546426

4.~~357129~~084263

83.~~789678~~131345

137.~~146807~~215608

~~987~~930.~~125345~~415081

0811/01/04

0811/30/04

30/360

100.00

1,000.000000

~~47,667~~0.~~200000~~000000

0.000000

~~47,667~~0.~~200000~~000000

1,000.000000

Page 2 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Distribution to Date -

Current

Original

Unscheduled

Scheduled

Total

Realized

Deferred

Principal

Class

Face Value

Interest

Principal

Distribution

Loss

Interest

Balance

(1)

(2)

(3)

(4)

(5)=(3)+(4)

(6)=(2)+(5)

(7)

(8)

(9)=(1)-(5)-(7)+(8)

A-1

106,813,929.00

13,~~948~~045,~~054~~108.8656

68,~~557~~645,~~363~~194.0142

13,~~222~~667,~~109~~991.8744

712,~~779~~313,~~472~~185.8886

915,~~727~~358,~~527~~294.7442

0.00

9994,~~034~~500,~~456~~743.1214

A-2

29,131,071.00

~~195~~350,~~652~~729.7189

12,~~788~~357,~~371~~780.6924

~~333~~1,~~302~~000,361.6828

23,~~121~~358,~~674~~141.3752

23,~~317~~708,~~327~~871.0841

0.00

2725,~~009~~772,~~396~~929.6348

A-3

0.00

~~748~~1,~~858~~125,686.7439

0.00

~~748~~1,~~858~~125,686.7439

0.00

A-4

73,048,000.00

12,~~586~~418,~~279~~839.6366

27,~~732~~475,~~628~~208.6704

19,~~062~~541,~~666~~930.5581

317,~~795~~017,~~295~~138.2285

519,~~381~~435,~~574~~978.8551

0.00

6956,~~252~~030,~~704~~861.7815

A-5

5,753,000.00

8492,~~233~~597.1795

34,~~438~~076,~~086~~855.6543

~~402~~1,~~962~~676,144.5057

35,~~841~~753,~~049~~000.1500

35,~~925~~845,~~282~~597.3295

0.00

~~1,911,950~~0.8500

A-6

3,000,000.00

65105,~~625~~000.00

0.00

65105,~~625~~000.00

0.00

3,000,000.00

A-7

25,512,000.00

~~558~~892,~~075~~920.00

0.00

~~558~~892,~~075~~920.00

0.00

25,512,000.00

385,093.00

0.00

2555,~~217~~238.7991

2,237.95

2757,~~455~~476.7486

0.00

~~357~~327,~~637~~616.2614

A-X

0.00

~~483~~725,~~103~~889.2896

0.00

~~483~~725,~~103~~889.2896

0.00

A-R

100.00

0.44

0.00

100.00

100.44

0.00

B-1

6,122,000.00

~~133~~210,~~646~~760.0866

0.0001

78425,~~818~~999.8314

78425,~~818~~999.8315

~~212~~636,~~464~~759.9181

0.00

65,~~043~~696,~~181~~000.1785

B-2

1,786,000.00

3861,~~989~~486.20

0.00

22124,~~994~~278.1974

61185,~~983~~764.3994

0.00

1,~~763~~661,~~005~~721.8126

B-3

1,276,000.00

2743,~~855~~928.6755

0.00

1688,~~428~~790.1142

44132,~~283~~718.7897

0.00

1,~~259~~187,~~571~~209.8958

B-4

893,000.00

1930,~~494~~743.6112

0.00

1162,~~497~~139.1038

3092,~~991~~882.7150

0.00

~~881~~830,~~502~~860.9062

B-5

383,000.00

813,~~361~~185.0745

0.00

426,~~931~~651.0105

1339,~~292~~836.0850

0.00

~~378~~356,~~068~~348.9995

B-6

1,020,571.00

2235,~~279~~134.5496

0.00

1371,~~139~~016.5035

35106,~~419~~151.0431

0.00

1949,~~007,431~~554.5065

100.00

9,671.09

0.00

9,671.09

0.00

100.00

Total

255,123,864.00

59,~~930~~161,~~180~~682.0988

1422,~~541~~610,~~667~~277.8105

316,~~171~~687,~~188~~641.2913

1739,~~712~~297,~~856~~918.1018

2348,~~643~~459,~~036~~601.1906

0.00

~~237~~215,~~411~~825,~~007~~945.9082

Interest Detail -

Pass

Prior Principal

Non-

Prior

Unscheduled

Paid or

Current

Through

(with Notional)

Accrued

Supported

Unpaid

Interest

Optimal

Deferred

Unpaid

Class

Rate

Balance

Interest

Interest SF

Interest

Adjustment

Interest

(1)

(2)

(3)

(4)

(5)=(1)-(2)+(3)+(4)

(6)

(7)=(5)-(6)

A-1

4.50000%

~~100~~96,~~855~~000,~~581~~993.6632

~~378~~360,~~208~~003.4372

0.00

~~378~~360,~~208~~003.4372

0.00

A-2

12.~~96500~~53000%

2726,~~506~~182,~~067~~088.2261

4555,~~041~~200.1957

0.00

4555,~~041~~200.1957

0.00

A-3

65.~~03500~~47000%

2726,~~506~~182,~~067~~088.2261

~~138~~119,~~332~~346.6069

0.00

~~138~~119,~~332~~346.6069

0.00

A-4

5.25000%

7257,~~252~~779,~~175~~868.5509

~~316~~252,~~103~~786.2792

0.00

~~316~~252,~~103~~786.2792

0.00

A-5

50.~~25000~~00000%

~~2,657,177~~0.8700

~~11,625~~0.1500

0.00

~~11,625~~0.1500

0.00

A-6

5.25000%

3,000,000.00

13,125.00

0.00

13,125.00

0.00

A-7

5.25000%

25,512,000.00

111,615.00

0.00

111,615.00

0.00

0.00000%

~~382~~328,~~762~~169.2619

0.00

A-X

0.~~49494~~44972%

~~224~~201,~~190~~256,~~306~~908.7580

9275,~~467~~424.1078

0.00

9275,~~467~~424.1078

9275,~~467~~424.1080

0.00

A-R

0.00000%

0.00

B-1

5.25000%

65,~~096~~715,~~991~~170.5995

2625,~~674~~003.3487

0.00

2625,~~674~~003.3487

0.00

B-2

5.25000%

1,~~778~~667,~~704~~313.1884

7,~~781~~294.8350

0.00

7,~~781~~294.8350

0.00

B-3

5.25000%

1,~~270~~191,~~787~~205.5218

5,~~559~~211.7052

0.00

5,~~559~~211.7052

0.00

B-4

5.25000%

~~889~~833,~~352~~656.0891

3,~~890~~647.9225

0.00

3,~~890~~647.9225

0.00

B-5

5.25000%

~~381~~357,~~435~~548.4426

1,~~668~~564.7827

0.00

1,~~668~~564.7827

0.00

B-6

5.25000%

1952,~~016,401~~750.9941

4,~~446~~168.7628

0.00

4,~~446~~168.7628

0.00

0.00000%

100.00

0.00

~~4,766~~0.7200

0.00

Total

~~495~~446,~~295~~959,~~911~~862.3317

1,~~156~~034,~~540~~392.0737

0.00

1,~~156~~034,~~540~~392.0737

1,~~161~~034,~~306~~392.7939

0.00

Page 3 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Collection Account Report

SUMMARY

Total

Principal Collections

63,~~188~~694,~~529~~918.4694

Principal Withrawals

0.00

Principal Other Accounts

0.00

TOTAL NET PRINCIPAL

63,~~188~~694,~~529~~918.4694

Interest Collections

1,~~174~~045,~~191~~715.6089

Interest Withdrawals

-0.00

Interest Other Accounts

~~4,766~~0.7200

Interest Fees

-1711,~~651~~323.5350

TOTAL NET INTEREST

1,~~161~~034,~~306~~392.7939

TOTAL AVAILABLE FUNDS FOR DISTRIBUTION

74,~~349~~729,~~836~~311.2533

PRINCIPAL - COLLECTIONS

Total

Scheduled Principal Received

~~251~~233,~~232~~904.7524

Curtailments

5528,~~292~~669.1618

Prepayments In Full

32,~~986~~930,~~137~~516.6749

Repurchased/Substitutions

1501,~~895,866~~829.8803

Liquidations

0.00

Insurance Principal

0.00

Other Additional Principal

0.00

Delinquent Principal

-~~191~~195,~~156~~675.5181

Realized Losses

-0.00

Advanced Principal

~~191~~195,~~156~~675.5181

TOTAL PRINCIPAL COLLECTED

63,~~188~~694,~~529~~918.4694

PRINCIPAL - WITHDRAWALS

SPACE INTENTIONALLY LEFT BLANK

PRINCIPAL - OTHER ACCOUNTS

Total

TOTAL PRINCIPAL OTHER ACCOUNTS

0.00

Page 4 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

INTEREST - COLLECTIONS

Total

Scheduled Interest

1,~~211~~091,~~593~~056.0510

Repurchased/Substitution Interest

102,~~936~~770.3551

Liquidation Interest

0.00

Insurance Interest

0.00

Other Additional Interest

0.00

Prepayment Interest Shortfalls

-2,~~902~~381.2717

Delinquent Interest

-~~922~~912,~~767~~700.1963

Compensating Interest

2,~~902~~381.2717

Civil Relief Act Shortfalls

-0.00

Interest Advanced

~~874~~864,~~429~~589.3891

TOTAL INTEREST COLLECTED

1,~~174~~045,~~191~~715.6089

INTEREST - WITHDRAWALS

Total

TOTAL INTEREST WITHDRAWALS

0.00

INTEREST - OTHER ACCOUNTS

Total

Prepayment Charges

~~4,766~~0.7200

TOTAL INTEREST OTHER ACCOUNTS

~~4,766~~0.7200

INTEREST - FEES

Total

Current Servicing Fees

159,~~621~~494.5416

Trustee Fees

21,~~029~~829.9934

TOTAL INTEREST FEES

1711,~~651~~323.5350

Page 5 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Credit Enhancement Report

ACCOUNTS

SPACE INTENTIONALLY LEFT BLANK

INSURANCE

SPACE INTENTIONALLY LEFT BLANK

STRUCTURAL FEATURES

SPACE INTENTIONALLY LEFT BLANK

Page 6 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Collateral Report

COLLATERAL

Total

Loan Count:

Original

771

Prior

~~737~~633

Prefunding

Scheduled Paid Offs

-0

Full Voluntary Prepayments

-1511

Repurchases

-101

Liquidations

-0

Current

~~712~~621

Principal Balance:

Original

255,123,765.35

Prior

~~243~~219,~~599~~520,~~438~~766.6807

Prefunding

0.00

Scheduled Principal

-~~251~~233,~~232~~904.7524

Partial Prepayments

-5528,~~292~~669.1618

Full Voluntary Prepayments

-32,~~986~~930,~~137~~516.6749

Repurchases

-1501,~~895,866~~829.8803

Liquidations

-0.00

Current

~~237~~215,~~410~~825,~~909~~847.2213

PREFUNDING

SPACE INTENTIONALLY LEFT BLANK

Page 7 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

CHARACTERISTICS

Total

Weighted Average Coupon Original

6.04407%

Weighted Average Coupon Prior

65.~~02712~~98978%

Weighted Average Coupon Current

65.~~02233~~97935%

Weighted Average Months to Maturity Original

354

Weighted Average Months to Maturity Prior

~~351~~348

Weighted Average Months to Maturity Current

~~350~~347

Weighted Avg Remaining Amortization Term Original

354

Weighted Avg Remaining Amortization Term Prior

~~351~~348

Weighted Avg Remaining Amortization Term Current

~~350~~347

Weighted Average Seasoning Original

3.64

Weighted Average Seasoning Prior

69.4041

Weighted Average Seasoning Current

710.3040

Page 8 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

ARM CHARACTERISTICS

Total

Weighted Average Margin Original

0.00000%

Weighted Average Margin Prior

0.00000%

Weighted Average Margin Current

0.00000%

Weighted Average Max Rate Original

0.00000%

Weighted Average Max Rate Prior

0.00000%

Weighted Average Max Rate Current

0.00000%

Weighted Average Min Rate Original

0.00000%

Weighted Average Min Rate Prior

0.00000%

Weighted Average Min Rate Current

0.00000%

Weighted Average Cap Up Original

0.00000%

Weighted Average Cap Up Prior

0.00000%

Weighted Average Cap Up Current

0.00000%

Weighted Average Cap Down Original

0.00000%

Weighted Average Cap Down Prior

0.00000%

Weighted Average Cap Down Current

0.00000%

SERVICING FEES & ADVANCES

Total

Current Servicing Fees

159,~~621~~494.5416

Delinquent Servicing Fees

48,~~337~~110.8172

TOTAL SERVICING FEES

6357,~~959~~604.3688

Total Servicing Fees

6357,~~959~~604.3688

Compensating Interest

-2,~~902~~381.2717

Delinquent Servicing Fees

-48,~~337~~110.8172

COLLECTED SERVICING FEES

127,~~719~~113.2800

Total Advaced Interest

~~874~~864,~~429~~589.3891

Total Advaced Principal

~~191~~195,~~156~~675.5181

Aggregate Advances with respect to this Distribution

1,~~065~~060,~~585~~265.8972

ADDITIONAL COLLATERAL INFORMATION

Total

Prepayment Interest Shortfall (PPIS)

2,~~902~~381.2717

Compensating Interest

-2,~~902~~381.2717

Net Prepayment Interest Shortfall (PPIS)

0.00

Weighted Average Net Mortgage Rate

5.~~697255~~654458%

Page 9 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Delinquency Report

TOTAL

< 1 PAYMENT

1 PAYMENT

2 PAYMENTS

3+ PAYMENTS

TOTAL

DELINQUENT

Balance

32,~~602~~574,~~182~~961.3639

~~154~~1,~~867~~594,687.1218

~~143~~705,~~934~~615.4732

34,~~900~~875,~~983~~263.9589

% Balance

1.5219%

0.0774%

0.0633%

12.6426%

# Loans

109

1315

% # Loans

1.4045%

0.1464%

0.2832%

12.8342%

FORECLOSURE

Balance

0.00

0248,211.0023

% Balance

0.00%

0.0012%

# Loans

% # Loans

0.00%

0.0032%

BANKRUPTCY

Balance

0.00

% Balance

0.00%

# Loans

% # Loans

0.00%

REO

Balance

0.00

% Balance

0.00%

# Loans

% # Loans

0.00%

TOTAL

Balance

0.00

32,~~602~~574,~~182~~961.3639

~~154~~1,~~867~~594,687.1218

~~143~~953,~~934~~826.4755

35,~~900~~123,~~983~~475.9512

% Balance

0.00%

1.5219%

0.0774%

0.0644%

12.6437%

# Loans

109

1317

% # Loans

0.00%

1.4045%

0.1464%

0.2864%

12.8374%

Page 10 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

REO Report

Loan Number

Original

Stated

Current

State &

First

Principal

Paid to

Note

LTV at

Original

Payment

Loan Group

Balance

Date

Rate

Origination

Term

Date

SPACE INTENTIONALLY LEFT BLANK

TOTAL

Page 11 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Foreclosure Report

Loan Number

Original

Stated

Current

State &

First

Principal

Paid to

Note

LTV at

Original

Payment

Loan Group

Balance

Date

Rate

Origination

Term

Date

TOTAL

323522 1

100,800.00

93,703.01

01-Apr-2004

7.000%

OR - 80.00%

360

01-Jun-1998

2155643 1

156,560.00

154,508.22

01-Jun-2004

7.875%

CT - 95.00%

360

01-Jul-2003

TOTAL

257,360.00

248,211.23

Page 12 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Prepayment Report

VOLUNTARY PREPAYMENTS

Total

Current

Number of Paid in Full Loans

1511

Number of Repurchased Loans

101

Total Number of Loans Prepaid in Full

2512

Curtailments Amount

5528,~~292~~669.1618

Paid in Full Balance

32,~~986~~930,~~137~~516.6749

Repurchased Loans Balance

1501,~~895,866~~829.8803

Total Prepayment Amount

53,~~937~~461,~~296~~014.7170

Cumulative

Number of Paid in Full Loans

4976

Number of Repurchased Loans

1074

Total Number of Loans Prepaid in Full

59150

Paid in Full Balance

1422,~~123~~119,~~689~~507.1665

Repurchased Loans Balance

114,~~895~~701,~~866~~745.8894

Curtailments Amount

~~417~~488,~~534~~810.1280

Total Prepayment Amount

1637,~~437~~310,~~090~~064.1639

Page 13 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

VOLUNTARY PREPAYMENTS RATES

Total

SMM

21.4458%

3 Months Avg SMM

13.2403%

12 Months Avg SMM

1.3397%

Avg SMM Since Cut-off

1.3397%

CPR

2517.6538%

3 Months Avg CPR

1330.8784%

12 Months Avg CPR

1421.8222%

Avg CPR Since Cut-off

1421.8222%

PSA

~~1,755~~835.9048%

3 Months Avg PSA Approximation

1,~~088~~642.8659%

12 Months Avg PSA Approximation

1,~~360~~532.7554%

Avg PSA Since Cut-off Approximation

1,~~360~~532.7554%

Page 14 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

PREPAYMENT CALCULATION METHODOLOGY

Single Monthly Mortality (SMM): (Voluntary partial and full prepayments + Repurchases + Liquidations )/(Beg Principal Balance - Sched Principal)

Conditional Prepayment Rate (CPR): 1-((1-SMM)^12)

PSA Standard Prepayment Model: CPR/(0.002*min(30,WAS))

Average SMM over period between nth month and mth month (AvgSMMn,m): [(1-SMMn)*(1-SMMn+1)*...*(1-SMMm)]^(1/months in period n,m)

Average CPR over period between the nth month and mth month (AvgCPRn,m): 1-((1-AvgSMMn,m)^12)

Average PSA Approximation over period between the nth month and mth month: AvgCPRn,m/(0.002*Avg WASn,m))

Average WASn,m: (min(30,WASn)+min(30,WASn+1)+...+min(30,WASm)/(number of months in the period n,m)

Weighted Average Seasoning (WAS)

Note: Prepayment rates are calculated since deal issue date and include partial and full voluntary prepayments, liquidations, and repurchases.

Dates correspond to distribution dates.

Page 15 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Prepayment Detail Report

Prepayment Detail Report - Mortgage Loans Prepaid in Full During Current Distribution

Loan Number

Original

Current

State &

Type Prepayment

First

Loan

Principal

Prepayment

Note

LTV at

Payment

Loan Group

Status

Balance

Amount

Date

Rate

Origination

Original Term

Date

239425 1

103,600.00

91,144.78

17-Aug-2004

6.875%

NY - 70.00%

Paid Off - 360

01-Jul-1997

606131 1

175,500.00

161,824.15

02-Dec-2004

7.625%

CA - 90.00%

Paid Off - 360

8/1/2000

257842 1

58,500.00

39,718.82

14-Sep-2004

7.875%

NY - 90.00%

Paid Off - 180

01-Oct-1997

3157680 1

135,000.00

133,713.65

01-Dec-2004

7.125%

FL - 45.00%

Paid Off - 360

1/1/2004

3068072 1

507,000.00

495,765.30

20-Aug-2004

5.250%

CA - 65.76%

Paid Off - 360

01-Oct-2003

3160084 1

390,000.00

386,757.25

29-Nov-2004

6.500%

MA - 77.38%

Paid Off - 360

3/1/2004

3153604 1

167,000.00

166,836.96

23-Aug-2004

6.875%

RI - 69.87%

Paid Off - 360

01-Mar-2003

3160634 1

442,100.00

438,431.67

29-Nov-2004

5.875%

PA - 75.57%

Paid Off - 360

4/1/2004

3154359 1

151,000.00

149,631.63

31-Aug-2004

7.125%

ME - 83.43%

Paid Off - 360

01-Oct-2003

3292589 1

80,000.00

79,600.77

22-Nov-2004

7.000%

NH - 19.09%

Paid Off - 360

6/1/2004

3160086 1

476,000.00

470,212.37

13-Sep-2004

6.125%

CA - 74.96%

Paid Off - 360

01-Mar-2004

3421535 1

210,000.00

208,549.20

24-Nov-2004

6.125%

CA - 64.62%

Paid Off - 360

5/1/2004

3160637 1

520,000.00

515,742.44

19-Aug-2004

5.750%

VA - 66.67%

Paid Off - 360

01-Apr-2004

3546801 1

136,200.00

135,211.59

02-Dec-2004

5.875%

MD - 66.44%

Paid Off - 360

5/1/2004

3236873 1

251,750.00

250,611.34

10-Sep-2004

7.500%

DC - 95.00%

Paid Off - 360

01-Mar-2004

3610349 1

452,000.00

449,573.97

19-Nov-2004

6.625%

DC - 80.00%

Paid Off - 360

6/1/2004

3308432 1

578,000.00

573,536.90

01-Sep-2004

5.750%

CT - 85.00%

Paid Off - 360

01-Feb-2004

3628424 1

476,000.00

472,320.29

06-Dec-2004

6.250%

CA - 80.00%

Paid Off - 360

4/1/2004

3434653 1

125,500.00

125,094.96

03-Sep-2004

7.125%

FL - 59.20%

Paid Off - 360

01-May-2004

3628837 1

390,000.00

389,976.96

18-Nov-2004

6.000%

CA - 60.00%

Paid Off - 360

4/1/2004

3591176 1

155,100.00

154,384.12

27-Aug-2004

6.375%

TX - 94.98%

Paid Off - 360

01-May-2004

3660148 1

75,000.00

74,556.99

01-Dec-2004

6.125%

FL - 39.27%

Paid Off - 360

6/1/2004

3596124 1

115,369.00

114,938.18

19-Aug-2004

6.375%

VA - 42.89%

Paid Off - 360

01-May-2004

3485961 1

505,000.00

501,829.03

30-Nov-2004

6.625%

NY - 51.79%

Repur/Subs - 360

5/1/2004

3611770 1

206,157.00

205,303.89

01-Sep-2004

6.500%

CA - 62.28%

Paid Off - 360

01-May-2004

TOTAL

3,466,800.00

3,432,345.52

3652229 1

157,000.00

156,550.75

01-Sep-2004

6.250%

NY - 46.18%

Paid Off - 360

01-Jun-2004

3704775 1

477,000.00

476,665.23

27-Aug-2004

7.875%

MI - 90.00%

Paid Off - 360

01-May-2004

278128 1

166,800.00

155,136.21

31-Aug-2004

8.250%

ID - 80.00%

Repur/Subs - 360

01-Nov-1997

2904509 1

304,000.00

316,288.46

31-Aug-2004

6.750%

NY - 80.00%

Repur/Subs - 360

01-Sep-2003

3156978 1

110,000.00

109,263.79

31-Aug-2004

7.000%

NH - 40.74%

Repur/Subs - 360

01-Jan-2004

3156979 1

110,000.00

109,263.79

31-Aug-2004

7.000%

NH - 40.74%

Repur/Subs - 360

01-Jan-2004

3429026 1

110,000.00

109,627.17

31-Aug-2004

6.875%

FL - 64.33%

Repur/Subs - 360

01-May-2004

3454583 1

147,124.00

146,409.96

31-Aug-2004

7.000%

CA - 48.72%

Repur/Subs - 360

01-Apr-2004

3477565 1

350,000.00

348,543.43

31-Aug-2004

6.625%

AZ - 70.00%

Repur/Subs - 360

01-May-2004

3544418 1

210,000.00

209,270.63

31-Aug-2004

6.750%

CA - 51.85%

Repur/Subs - 360

01-May-2004

3589011 1

260,447.00

259,564.22

31-Aug-2004

6.875%

MA - 65.94%

Repur/Subs - 360

01-May-2004

3591909 1

132,961.00

132,499.22

31-Aug-2004

6.750%

AZ - 64.23%

Repur/Subs - 360

01-May-2004

TOTAL

5,950,308.00

5,882,004.55

Page 16 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Realized Loss Report

COLLATERAL REALIZED LOSSES

Total

Current

Number of Loans Liquidated

Collateral Principal Realized Loss/(Gain) Amount

0.00

Collateral Interest Realized Loss/(Gain) Amount

0.00

Net Liquidation Proceeds

0.00

Cumulative

Number of Loans Liquidated

Collateral Realized Loss/(Gain) Amount

0.00

Net Liquidation Proceeds

0.00

Special Hazard Loss Coverage Amt

2,500,000.00

Fraud Loss Coverage Amt

2,500,000.00

Bankrupt Loss Coverage Amt

100,000.00

Class B-1 Writedown Amount

0.00

Class B-2 Writedown Amount

0.00

Class B-3 Writedown Amount

0.00

Class B-4 Writedown Amount

0.00

Class B-5 Writedown Amount

0.00

Class B-6 Writedown Amount

0.00

Page 17 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

DEFAULT SPEEDS

Total

MDR

0.00%

3 Months Avg MDR

0.00%

12 Months Avg MDR

0.00%

Avg MDR Since Cut-off

0.00%

CDR

0.00%

3 Months Avg CDR

0.00%

12 Months Avg CDR

0.00%

Avg CDR Since Cut-off

0.00%

SDA

0.00%

3 Months Avg SDA Approximation

0.00%

12 Months Avg SDA Approximation

0.00%

Avg SDA Since Cut-off Approximation

0.00%

Loss Severity Approximation for Current Period

0.00%

3 Months Avg Loss Severity Approximation

0.00%

12 Months Avg Loss Severity Approximation

0.00%

Avg Loss Severity Approximation Since Cut-off

0.00%

Page 18 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

COLLATERAL REALIZED LOSS CALCULATION METHODOLOGY

Monthly Default Rate (MDR): (Beg Principal Balance of Liquidated Loans)/(Total Beg Principal Balance)

Conditional Default Rate (CDR): 1-((1-MDR)^12)

SDA Standard Default Assumption: CDR/IF(WAS<61,MIN(30,WAS)*0.02,MAX(0.03,MIN(30,WAS)*0.02-0.0095*(WAS-60)))

Average MDR over period between nth month and mth month (AvgMDRn,m): [(1-MDRn)*(1-MDRn+1)*...*(1-MDRm)]^(1/months in period n,m)

Average CDR over period between the nth month and mth month (AvgCDRn,m): 1-((1-AvgMDRn,m)^12)

Average SDA Approximation over period between the nth month and mth month:

AvgCDRn,m/IF(Avg WASn,m<61,MIN(30,Avg WASn,m)*0.02,MAX(0.03,MIN(30,Avg WASn,m)*0.02-0.0095*(Avg WASn,m-60)))

Average WASn,m: (WASn + WASn+1 +...+ WASm )/(number of months in the period n,m)

Loss Severity Approximation for current period: sum(Realized Loss Amount)/sum(Beg Principal Balance of Liquidated Loans)

Average Loss Severity Approximation over period between nth month and mth month: Avg(Loss Severityn,m)

Note: Default rates are calculated since deal issue date and include realized gains and additional realized losses and gains from prior periods.

Dates correspond to distribution dates.

Page 19 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Realized Loss Detail Report

Loan Number

~~Original~~Current

~~Prior~~State &

~~Current~~Prior

~~State &~~Realized

Cumulative

First

Loan

Note

LTV at

Original

Principal

Loss/(Gain)

Realized

Principal

Realized

Note

LTV at

Original

Payment

Loan Group

Status

Rate

Origination

Term

Balance

Revision

Loss/(Gain)

Loan Group

Balance

Loss/(Gain)

Rate

Origination

Term

Date

SPACE INTENTIONALLY LEFT BLANK

TOTAL

Page 20 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Triggers and Adj. Cert. Report

TRIGGER EVENTS

Total

Has Optional Termination Date Reached (0=No,1=Yes)

Has Sr. Prepay Stepdown Condition Occurred (0=No,1=Yes)

Has Sr. Credit Supp. Depletion Date Occured (0=No,1=Yes)

Have all Prepayment Penalties Expired? (0=No,1=Yes)

Has Special Haz. Cov. Term Date Occured (0=No,1=Yes)

Has Fraud Loss Coverage Term Date Occured (0=No,1=Yes)

Has BK Loss Cov. Term Date Occured (0=No,1=Yes)

ADJUSTABLE RATE CERTIFICATE INFORMATION

SPACE INTENTIONALLY LEFT BLANK

ADDITIONAL INFORMATION

Total

Current Senior Percentage

95.~~298976~~110397%

Next Senior Percentage

95.~~219318~~043256%

Current Subordinate Percentage

4.~~701024~~889603%

Next Subordinate Percentage

4.~~780682~~956744%

Senior Prepayment Percentage

100.000000%

Next Senior Prepayment Percentage

100.000000%

Subordinate Prepayment Percentage

0.000000%

Next Subordinate Prepayment Percentage

0.000000%

Page 21 of 22

IndyMac Residential Asset Securitization Trust 2004-A3

Mortgage Pass-Through Certificates

REMIC 2004-A3

2004-A3

September 27, 2004 Distribution

December 27, 2004 Distribution

Other Related Information

ADDITIONAL INFORMATION

Total

Current Scheduled Payments

1,~~462~~324,~~825~~960.8034

Current Scheduled Payments 1 Month Prior

1,~~491~~339,~~453~~840.3490

Current Scheduled Payments 2 Month Prior

1,~~497~~394,~~469~~927.0446

Current Scheduled Payments 3 Month Prior

1,~~526~~462,~~246~~825.3080

Current Scheduled Payments 4 Month Prior

1,~~544~~491,~~635~~453.4334

Current Scheduled Payments 5 Month Prior

01,497,469.0004

Current Scheduled Payments 6 Month Prior

01,526,246.0030

Current Scheduled Payments 7 Month Prior

01,544,635.0043

Current Scheduled Payments 8 Month Prior

0.00

Current Scheduled Payments 9 Month Prior

0.00

Current Scheduled Payments 10 Month Prior

0.00

Current Scheduled Payments 11 Month Prior

0.00

Delinquent 60+ Scheduled Payments

216,~~151~~088.1012

Delinq. 60+ Sched. Pmnts, 1 Month Prior

916,~~061~~392.4175

Delinq. 60+ Sched. Pmnts, 2 Month Prior

710,~~634~~412.6512

Delinq. 60+ Sched. Pmnts, 3 Month Prior

62,~~415~~151.5710

Delinq. 60+ Sched. Pmnts, 4 Month Prior

19,~~135~~061.1741

Delinq. 60+ Sched. Pmnts, 5 Month Prior

07,634.0065

Delinq. 60+ Sched. Pmnts, 6 Month Prior

06,415.0057

Delinq. 60+ Sched. Pmnts, 7 Month Prior

01,135.0017

Delinq. 60+ Sched. Pmnts, 8 Month Prior

0.00

Delinq. 60+ Sched. Pmnts, 9 Month Prior

0.00

Delinq. 60+ Sched. Pmnts, 10 Month Prior

0.00

Delinq. 60+ Sched. Pmnts, 11 Month Prior

0.00

Page 22 of 22

Filing Compare · Residential Asset Securitization Trust 2004-A3