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): ~~April~~September 2627, 2004 ~~INDYMAC~~(Date ~~MBS,~~of ~~INC.~~earliest asevent ~~Depositor,~~reported) ~~IndyMac~~Indymac ~~Bank,~~MBS ~~F.S.B.~~Inc (as ~~Seller~~Depositor ~~and as Master Servicer, and Deutsche Bank National Trust Company, as trustee~~ under the Pooling and Servicing Agreement, dated as of March 1, 2004, providing for the issuance of ~~IndyMac~~IndyMAc ~~MBS,~~INDX ~~Inc.~~Mortgage ~~Residential~~Loan ~~Asset-Securitization~~ Trust ~~Series~~ 2004-AR1 Mortgage Pass-Through Certificates, Series 2004-AR1.) ~~INDYMAC INDX MORTGAGE LOAN TRUST 2004-AR1~~ (Exact name of ~~Registrant~~registrant as specified in ~~its Charter~~charter) DELAWARE (State or Other Jurisdiction of Incorporation) 333-102888-18 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 58.01 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 79.01 Financial ~~Statement~~Statements and Exhibits (c) Exhibits: ~~(as~~Exhibit ~~noted~~No. inDescription ~~Item~~99.1 ~~5 above)~~ Monthly Remittance Statement to the Certificateholders dated as of ~~April~~September 2627, 2004. ~~SIGNATURE~~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, ~~not~~ in itits ~~individual~~ capacity, ~~but solely~~ as aTrustee ~~duly~~under ~~authorized agent of~~ the ~~Registrant pursuant to the~~ Pooling and Servicing Agreement, ~~dated~~on asbehalf of ~~March~~Indymac 1MBS Inc,~~2004.~~ Registrant Date: ~~Apr~~Sep 27, 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 ~~April~~September 2627, 2004.

	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	April 26, 2004 Distribution
	September 27, 2004 Distribution
	Contents
			TABLE OF CONTENTS
								Page
			1.	Contents				1
			2.	Certificate Payment Report				2
			3.	Collection Account Report				4
			4.	Credit Enhancement Report				7
			5.	Collateral Report				8
			6.	Delinquency Report				11
			7.	REO Report				14
			8.	Prepayment Report				15
			9.	Prepayment Detail Report				18
			10.	Realized Loss Report				19
			11.	Realized Loss Detail Report				22
			12.	Triggers, Adj. Rate Cert. and Miscellaneous Report				23
			13.	Other Related Information				24
			14.	Additional Certificate Report				25
				Total Number of Pages				25
			CONTACTS
				Administrator: Brent Hoyler
				Direct Phone Number: (714)247-6322
				Address: Deutsche Bank
				1761 E. St. Andrew Place, Santa Ana, CA 92705
				Web Site: https://www.corporatetrust.db.com/invr
				Factor Information: (800) 735-7777
				Main Phone Number: (714) 247-6000
ISSUANCE INFORMATION
	Seller:		IndyMac Bank					Cut-Off Date: March 1, 2004
	Certificate Insurer(s):							Closing Date: December 29, 2003
								First Payment Date: April 26, 2004
	Servicer(s):		IndyMac Bank Master Servicer
								Distribution Date: April 26, 2004
								Distribution Date: September 27, 2004
	Underwriter(s):		Goldman, Sachs & Co. Underwriter					Record Date: ~~March~~August 31, 2004
						Page 1 of 25					© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Certificate Payment Report for April 26, 2004 Distribution
	Certificate Payment Report for September 27, 2004 Distribution
	Distribution in Dollars - Current Period
					Prior						Current
	Class	Original			Principal			Total	Realized	Deferred	Principal
Class	Type	Face Value			Balance	Interest	Principal	Distribution	Losses	Interest	Balance
					(1)	(2)	(3)	(4)=(2)+(3)	(5)	(6)	(7)=(1)-(3)-(5)+(6)
1-A-1		219,843,000.00			~~219~~208,~~843~~408,~~000~~664.0067	~~254~~332,~~651~~585.4849	12,~~546~~836,~~225~~909.0096	13,~~800~~169,~~876~~495.4845	-	-	~~218~~205,~~296~~571,~~775~~754.0071
2-A-1		294,041,000.00			~~294~~278,~~041~~909,~~000~~399.0022	~~340~~445,~~597~~092.4992	24,~~812~~191,~~177~~106.4686	34,~~152~~636,~~774~~199.9578	-	-	~~291~~274,~~228~~718,~~822~~292.5435
A-X-1		-			-	~~342~~280,~~589~~327.3386	-	~~342~~280,~~589~~327.3386	-	-	-
A-X-2		-			-417,185.27	~~267~~458,~~102~~050.0293	-	~~267~~458,~~102~~050.0293	-	66123,~~810~~005.3392	66540,~~810~~191.3319
A-R		100.00			~~100.00~~-	0.2701	~~100.00~~-	~~100~~0.2701	-	-	-
B-1		15,388,000.00			15,~~388~~366,~~000~~903.0081	2027,~~645~~340.5728	131,~~463~~377.5312	3428,~~109~~717.1040	-	-	15,~~374~~365,~~536~~526.4768
B-2		7,144,000.00			7,~~144~~134,~~000~~205.0093	1316,~~335~~438.4740	~~6,250~~639.5534	1917,~~586~~077.0274	-	-	7,~~137~~133,~~749~~566.4559
B-3		4,121,000.00			4,~~121~~115,~~000~~350.0031	911,~~581~~368.3266	~~3,605~~368.6280	1311,~~186~~737.9446	-	-	4,~~117~~114,~~394~~981.3851
B-4		3,846,000.00			3,~~846~~840,~~000~~727.0032	810,~~941~~610.9501	~~3,365~~344.0119	1210,~~306~~954.9620	-	-	3,~~842~~840,~~634~~383.9913
B-5		3,022,000.00			3,~~022~~017,~~000~~856.0099	78,~~026~~336.1583	~~2,644~~270.0645	98,~~670~~607.2128	-	-	3,~~019~~017,~~355~~586.9454
B-6		2,205,478.27			2,~~205~~202,~~478~~454.2768	56,~~127~~084.7428	~~1,929~~197.6538	76,~~057~~281.3966	-	-	2,~~203~~202,~~548~~257.6230
P		100.00			100.00	-19,609.87	-	-19,609.87	-	-	100.00
Total		549,610,678.27			~~549~~523,~~610~~412,~~678~~848.2719	1,~~269~~615,~~598~~845.7854	47,~~389~~031,~~760~~214.8811	58,~~659~~647,~~359~~059.6665	-	66123,~~810~~005.3392	~~545~~516,~~287~~504,~~727~~640.7200
	Interest Accrual Detail				Current Period Factor Information per $1,000 of Original Face
						Orig. Principal	Prior				Current
	Period	Period				(with Notional)	Principal			Total	Principal
Class	Starting	Ending		Method	Cusip	Balance	Balance	Interest	Principal	Distribution	Balance
							(1)	(2)	(3)	(4)=(2)+(3)	(5)
1-A-1				A-30/360	45660NZX6	219,843,000.00	~~1,000~~947.~~000000~~988631	1.~~158333~~512832	712.~~033315~~904254	814.~~191648~~417086	~~992~~935.~~966685~~084377
2-A-1				A-30/360	45660NZY4	294,041,000.00	~~1,000~~948.~~000000~~539147	1.~~158333~~513710	914.~~563896~~253478	1015.~~722229~~767188	~~990~~934.~~436104~~285669
A-X-1				A-30/360	45660NZZ1	513,884,000.00	~~1,000~~818.~~000000~~262067	0.~~666667~~545508	-	0.~~666667~~545508	~~1,000~~785.~~000000~~843147
A-X-2				A-30/360	45660NA21	549,610,578.27	~~1,000~~952.~~000000~~333832	0.~~485984~~833410	-	0.~~485984~~833410	0939.~~121559~~764554
A-R				A-30/360	45660NA39	100.00	~~1,000.000000~~-	20.~~677000~~108000	~~1,000.000000~~-	~~1,002~~0.~~677000~~108000	-
B-1				A-30/360	45660NA47	15,388,000.00	~~1,000~~998.~~000000~~629049	1.~~341667~~776727	0.~~874937~~089493	21.~~216604~~866221	~~999~~998.~~125063~~539556
B-2				A-30/360	45660NA54	7,144,000.00	~~1,000~~998.~~000000~~629049	12.~~866667~~301008	0.~~874937~~089493	2.~~741603~~390501	~~999~~998.~~125063~~539556
B-3				A-30/360	45660NA62	4,121,000.00	~~1,000~~998.~~000000~~629049	2.~~324999~~758714	0.~~874937~~089493	32.~~199936~~848207	~~999~~998.~~125063~~539556
B-4				A-30/360	45660NA70	3,846,000.00	~~1,000~~998.~~000000~~629049	2.~~325001~~758713	0.~~874937~~089493	32.~~199938~~848206	~~999~~998.~~125063~~539556
B-5				A-30/360	45660NA88	3,022,000.00	~~1,000~~998.~~000000~~629049	2.~~324999~~758713	0.~~874937~~089493	32.~~199936~~848206	~~999~~998.~~125063~~539556
B-6				A-30/360	45660NA96	2,205,478.27	~~1,000~~998.~~000000~~629053	2.~~325000~~758712	0.~~874937~~089493	32.~~199937~~848206	~~999~~998.~~125063~~539560
P				F-30/360	IN040A1P1	100.00	1,000.000000	-196,098.700000	-	-196,098.700000	1,000.000000
							Page 2 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Certificate Payment Report for April 26, 2004 Distribution
	Certificate Payment Report for September 27, 2004 Distribution
	Distribution in Dollars - to Date
											Current
	Original				Unscheduled	Scheduled	Total	Total	Realized	Deferred	Principal
Class	Face Value		Interest		Principal	Principal	Principal	Distribution	Losses	Interest	Balance
	(1)		(2)		(3)	(4)	(5)=(3)+(4)	(6)=(2)+(5)	(7)	(8)	(9)=(1)-(5)-(7)+(8)
1-A-1	219,843,000.00		~~254~~1,~~651~~773,414.4898		-	114,~~546~~271,~~225~~245.0029	114,~~546~~271,~~225~~245.0029	116,~~800~~044,~~876~~660.4827	-	-	~~218~~205,~~296~~571,~~775~~754.0071
2-A-1	294,041,000.00		~~340~~2,~~597~~367,773.4941		-	219,~~812~~322,~~177~~707.4665	219,~~812~~322,~~177~~707.4665	321,~~152~~690,~~774~~481.9506	-	-	~~291~~274,~~228~~718,~~822~~292.5435
A-X-1	-		~~342~~1,~~589~~863,968.3354		-	-	-	~~342~~1,~~589~~863,968.3354	-	-	-
A-X-2	-		~~267~~2,~~102~~890,521.0277		-	-	-	~~267~~2,~~102~~890,521.0277	-	66540,~~810~~191.3319	66540,~~810~~191.3319
A-R	100.00		0.2730		-	100.00	100.00	100.2730	-	-	-
B-1	15,388,000.00		20144,~~645~~918.5755		-	1322,~~463~~473.5332	1322,~~463~~473.5332	34167,~~109~~391.1087	-	-	15,~~374~~365,~~536~~526.4768
B-2	7,144,000.00		1391,~~335~~012.4723		-	610,~~250~~433.5541	610,~~250~~433.5541	19101,~~586~~445.0264	-	-	7,~~137~~133,~~749~~566.4559
B-3	4,121,000.00		964,~~581~~451.3289		-	36,~~605~~018.6249	36,~~605~~018.6249	1370,~~186~~470.9438	-	-	4,~~117~~114,~~394~~981.3851
B-4	3,846,000.00		860,~~941~~150.9593		-	35,~~365~~616.0187	35,~~365~~616.0187	1265,~~306~~767.9680	-	-	3,~~842~~840,~~634~~383.9913
B-5	3,022,000.00		747,~~026~~263.1567		-	24,~~644~~413.0646	24,~~644~~413.0646	951,~~670~~677.2113	-	-	3,~~019~~017,~~355~~586.9454
B-6	2,205,478.27		534,~~127~~493.7439		-	13,~~929~~220.6597	13,~~929~~220.6597	737,~~057~~714.3936	-	-	2,~~203~~202,~~548~~257.6230
P	100.00		-154,764.16		-	-	-	-154,764.16	-	-	100.00
Total	549,610,678.27		19,~~269~~492,~~598~~733.7882		-	433,~~389~~646,~~760~~229.8846	433,~~389~~646,~~760~~229.8846	543,~~659~~138,~~359~~963.6628	-	66540,~~810~~191.3319	~~545~~516,~~287~~504,~~727~~640.7200
	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	Adjustments	Interest	Interest	Interest
					(1)	(2)	(3)	(4)	(5)=(1)-(2)+(3)+(4)	(6)	(7)=(5)-(6)
1-A-1	1.~~39000~~91500%	~~219~~208,~~843~~408,~~000~~664.0067			~~254~~332,~~651~~585.4849	-	-	-	~~254~~332,~~651~~585.4849	~~254~~332,~~651~~585.4849	-
2-A-1	1.~~39000~~91500%	~~294~~278,~~041~~909,~~000~~399.0022			~~340~~445,~~597~~092.4992	-	-	-	~~340~~445,~~597~~092.4992	~~340~~445,~~597~~092.4992	-
A-X-1	0.80000%	~~513~~420,~~884~~491,~~000~~784.00			~~342~~280,~~589~~327.3386	-	-0.01	-	~~342~~280,~~589~~327.3387	~~342~~280,~~589~~327.3386	-0.01
A-X-2	01.~~74417~~33216%	~~549~~523,~~610~~412,~~578~~748.2718			~~340~~581,~~834~~056.3585	-	-	-	~~340~~581,~~834~~056.3585	~~333~~581,~~912~~056.3585	-
A-R	3.~~00309~~98145%	~~100.00~~-			~~0.25~~-	-	-	-	~~0.25~~-	0.2701	-
B-1	12.~~61000~~13500%	15,~~388~~366,~~000~~903.0081			2027,~~645~~340.5728	-	-	-	2027,~~645~~340.5728	2027,~~645~~340.5728	-
B-2	2.~~18840~~76500%	7,~~144~~134,~~000~~205.0093			1316,~~028~~438.2840	-	-	-	1316,~~028~~438.2840	1316,~~335~~438.4740	-
B-3	23.~~18840~~31500%	4,~~121~~115,~~000~~350.0031			711,~~515~~368.3366	-	-	-	711,~~515~~368.3366	911,~~581~~368.3266	-
B-4	23.~~18840~~31500%	3,~~846~~840,~~000~~727.0032			710,~~013~~610.8301	-	-	-	710,~~013~~610.8301	810,~~941~~610.9501	-
B-5	23.~~18840~~31500%	3,~~022~~017,~~000~~856.0099			58,~~511~~336.1283	-	-	-	58,~~511~~336.1283	78,~~026~~336.1583	-
B-6	23.~~18840~~31500%	2,~~205~~202,~~478~~454.2768			46,~~022~~084.0628	-	-	-	46,~~022~~084.0628	56,~~127~~084.7428	-
P		100.00			-	-	-	-	-	-19,609.87	-
Total		1,~~613~~466,~~105~~900,~~256~~195.5410			1,~~336~~719,~~409~~241.0958	-	-0.01	-	1,~~336~~719,~~409~~241.0959	1,~~336~~738,~~409~~851.1146	-0.01
							Page 3 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Collection Account Report for April 26, 2004 Distribution
	Collection Account Report for September 27, 2004 Distribution
	Collection Account Report
SUMMARY						GROUP 2	GROUP 1	TOTAL
	Principal Collections					24,~~790~~124,~~775~~075.4716	12,~~532~~784,~~175~~133.0803	46,~~322~~908,~~950~~208.5519
	Principal Withdrawals					0.00	0.00	0.00
	Principal Other Accounts					0.00	0.00	0.00
	TOTAL PRINCIPAL					24,~~790~~124,~~775~~075.4716	12,~~532~~784,~~175~~133.0803	46,~~322~~908,~~950~~208.5519
	Interest Collections					~~847~~996,~~964~~593.2670	~~662~~761,~~903~~402.1240	1,~~510~~757,~~867~~996.3810
	Interest Withdrawals					0.00	0.00	0.00
	Interest Other Accounts					0.00	019,609.0087	019,609.0087
	Interest Fees					(9920,~~979~~067.4987)	(7418,~~478~~686.7865)	(~~174~~38,~~458~~754.2751)
	TOTAL INTEREST					~~747~~976,~~984~~525.7783	~~588~~762,~~424~~325.3462	1,~~336~~738,~~409~~851.1146
	TOTAL AVAILABLE FUNDS TO BONDHOLDERS					35,~~538~~100,~~760~~600.2499	23,~~120~~546,~~599~~458.4265	58,~~659~~647,~~359~~059.6665
	Interest Payable to Bondholders					~~747~~976,~~984~~525.7783	~~588~~762,~~424~~325.3462	1,~~336~~738,~~409~~851.1146
PRINCIPAL - COLLECTIONS						GROUP 2	GROUP 1	TOTAL
	Scheduled Principal					~~223~~26,~~570~~525.7012	~~152~~20,~~303~~381.2110	246,~~943,078~~906.6822
	Curtailments					8599,~~320~~704.9412	~~132~~118,~~699~~136.2554	~~356~~217,~~269~~840.9566
	Prepayments in Full					23,~~481~~997,~~883~~845.8392	12,~~142~~645,~~172~~615.6239	16,~~227~~643,~~493~~461.5631
	Repurchases/Substitutions					0.00	~~105,000~~0.00	~~2,586,883~~0.8300
	Liquidations					0.00	0.00	0.00
	Insurance Principal					0.00	0.00	0.00
	Other Additional Principal					0.00	0.00	0.00
	LESS: Delinquent Principal					0(18,675.0018)	(9215,840.0439)	(9234,515.0457)
	LESS: Realized Losses					0.00	0.00	0.00
	PLUS: Recoveries					0.00	0.00	0.00
	PLUS: Substitution Shortfall Principal					0.00	0.00	0.00
	PLUS: Principal Loan Adjustments					0.00	0.00	0.00
	PLUS: Principal Advanced					018,675.0018	9215,840.0439	9234,515.0457
	TOTAL PRINCIPAL					24,~~790~~124,~~775~~075.4716	12,~~532~~784,~~175~~133.0803	46,~~322~~908,~~950~~208.5519
				Page 4 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Collection Account Report for April 26, 2004 Distribution
	Collection Account Report for September 27, 2004 Distribution
	Collection Account Report
PRINCIPAL - WITHDRAWALS						GROUP 2	GROUP 1	TOTAL
SPACE INTENTIONALLY LEFT BLANK
PRINCIPAL - OTHER ACCOUNTS						GROUP 2	GROUP 1	TOTAL
	TOTAL PRINCIPAL OTHER ACCOUNTS					0.00	0.00	0.00
INTEREST - COLLECTIONS						GROUP 2	GROUP 1	TOTAL
	Scheduled Interest					~~847~~1,~~964~~071,760.2694	~~663~~813,~~004~~882.5828	1,~~510~~885,~~968~~643.8422
	Repurchases/Substitutions					0.00	~~170~~0.6300	~~170~~0.6300
	Liquidations					0.00	0.00	0.00
	Insurance Interest					0.00	0.00	0.00
	Other Additional Interest					0.00	0.00	0.00
	LESS: Prepayment Interest Shortfalls					(2,~~225~~115.5997)	(~~2,022~~737.9378)	(2,~~022~~853.9375)
	LESS: Delinquent Interest					0(861,364.0048)	(2611,~~894~~210.4448)	(21,~~894~~472,574.4496)
	LESS: Interest Realized Losses					0.00	0.00	0.00
	PLUS: Compensating Interest					2,~~225~~115.5997	~~2,022~~737.9378	42,~~248~~853.5275
	LESS: Civil Relief Act Shorfalls					0.00	0.00	0.00
	PLUS: Substiution Shortfall Interest					0.00	0.00	0.00
	PLUS: Interest Loan Adjustments					0.00	0.00	0.00
	LESS: Excess, Special Hazard, Fraud, & Bankruptcy Interest Losses					0.00	0.00	0.00
	Interest Advanced					0786,197.0024	2558,~~622~~730.3560	21,~~622~~344,927.3584
	TOTAL INTEREST					~~847~~996,~~964~~593.2670	~~662~~761,~~903~~402.1240	1,~~510~~757,~~867~~996.3810
				Page 5 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Collection Account Report for April 26, 2004 Distribution
	Collection Account Report for September 27, 2004 Distribution
	Collection Account Report
INTEREST - WITHDRAWALS						GROUP 2	GROUP 1	TOTAL
SPACE INTENTIONALLY LEFT BLANK
INTEREST - OTHER ACCOUNTS						GROUP 2	GROUP 1	TOTAL
	Prepayment Penalties					0.00	019,609.0087	019,609.0087
	TOTAL INTEREST OTHER ACCOUNTS					0.00	019,609.0087	019,609.0087
INTEREST - FEES						GROUP 2	GROUP 1	TOTAL
	Current Servicing Fees					9818,~~276~~445.0425	7317,~~205~~474.1711	~~171~~35,~~481~~919.2136
	Trustee Fees					1,~~703~~622.4562	1,~~273~~212.6154	2,~~977~~835.0615
	PMI Fees					0.00	0.00	0.00
	TOTAL INTEREST FEES					9920,~~979~~067.4987	7418,~~478~~686.7865	~~174~~38,~~458~~754.2751
				Page 6 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Credit Enhancement Report for April 26, 2004 Distribution
	Credit Enhancement Report for September 27, 2004 Distribution
	Credit Enhancement Report
ACCOUNTS						GROUP 2	GROUP 1	TOTAL
SPACE INTENTIONALLY LEFT BLANK
INSURANCE						GROUP 2	GROUP 1	TOTAL
SPACE INTENTIONALLY LEFT BLANK
STRUCTURAL FEATURES						GROUP 2	GROUP 1	TOTAL
SPACE INTENTIONALLY LEFT BLANK
				Page 7 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Collateral Report for April 26, 2004 Distribution
	Collateral Report for September 27, 2004 Distribution
	Collateral Report
COLLATERAL						GROUP 2	GROUP 1	TOTAL
	Loan Count:
	Original					800	1196	1996
	Prior					-764	-1,146	-1,910
	Prefunding					-	-	-
	Scheduled Paid Offs					-	-	-
	Full Voluntary Prepayments					(610)	(513)	(1123)
	Repurchases					-	~~(1)~~-	~~(1)~~-
	Liquidations					-	-	-
	Current					~~794~~754	1,~~190~~133	1,~~984~~887
	Principal Balance:
	Original					314,483,322.16	235,127,256.11	549,610,578.27
	Prior					-299,559,981.97	-223,852,766.21	-523,412,748.18
	Prefunding					-	-	-
	Scheduled Principal					(~~223~~26,~~570~~525.7012)	(~~152~~20,~~303~~381.2110)	(~~375~~46,~~873~~906.9122)
	Partial and Full Voluntary Prepayments					(24,~~567~~097,~~204~~550.7704)	(12,~~274~~763,~~871~~751.8793)	(36,~~842~~861,~~076~~301.6497)
	Repurchases					-	~~(105,000.00)~~-	~~(105,000.00)~~-
	Liquidations					-	-	-
	Current					~~311~~295,~~692~~435,~~546~~906.6981	~~233~~221,~~595~~068,~~081~~633.0318	~~545~~516,~~287~~504,~~627~~539.7299
PREFUNDING						GROUP 2	GROUP 1	TOTAL
SPACE INTENTIONALLY LEFT BLANK
	Group 1
	Group 2
Current Prin Balance by Groups (in millions of dollars)					Total Current Principal Balance (in millions of dollars)
				Page 8 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Collateral Report for April 26, 2004 Distribution
	Collateral Report for September 27, 2004 Distribution
	Collateral Report
CHARACTERISTICS						GROUP 2	GROUP 1	TOTAL
	Weighted Average Coupon Original					3.235647%	3.384594%	3.299368%
	Weighted Average Coupon Prior					4.200630%	4.271385%	4.230921%
	Weighted Average Coupon Current					34.~~235647~~293341%	34.~~384594~~362951%	34.~~299368~~323112%
	Weighted Average Months to Maturity Original					359	359	359
	Weighted Average Months to Maturity Prior					-355	-355	-355
	Weighted Average Months to Maturity Current					~~359~~354	~~359~~354	~~359~~354
	Weighted Avg Remaining Amortization Term Original					358	358	358
	Weighted Avg Remaining Amortization Term Prior					-354	-354	-354
	Weighted Avg Remaining Amortization Term Current					~~358~~353	~~358~~353	~~358~~353
	Weighted Average Seasoning Original					1.79	1.81	1.80
	Weighted Average Seasoning Prior					-5.79	-5.80	-5.79
	Weighted Average Seasoning Current					16.79	16.8180	16.8079
Note: Original information refers to deal issue.
	Group 1
	Group 2
WAC by Groups					Total WAC
WARAT by Groups					Total WARAT
Note: Dates correspond to distribution dates.
				Page 9 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Collateral Report for April 26, 2004 Distribution
	Collateral Report for September 27, 2004 Distribution
	Collateral Report
ARM CHARACTERISTICS						GROUP 2	GROUP 1	TOTAL
	Weighted Average Margin Original					2.905%	2.986%
	Weighted Average Margin Prior					2.909%	2.984%
	Weighted Average Margin Current					2.~~905~~909%	2.~~986~~982%
	Weighted Average Max Rate Original					9.126%	9.230%
	Weighted Average Max Rate Prior					9.137%	9.227%
	Weighted Average Max Rate Current					9.~~126~~137%	9.~~230~~228%
	Weighted Average Min Rate Original					1.250%	1.250%
	Weighted Average Min Rate Prior					1.250%	1.250%
	Weighted Average Min Rate Current					1.250%	1.250%
	Weighted Average Cap Up Original
	Weighted Average Cap Up Prior
	Weighted Average Cap Up Current
	Weighted Average Cap Down Original
	Weighted Average Cap Down Prior
	Weighted Average Cap Down Current
Note: Original information refers to deal issue.
SERVICING FEES / ADVANCES						GROUP 2	GROUP 1	TOTAL
	Current Servicing Fees					9818,~~276~~445.0425	7317,~~205~~474.1711	~~171~~35,~~481~~919.2136
	Delinquent Servicing Fees					075,167.0024	~~272~~52,479.0988	~~272~~127,647.0912
	TOTAL SERVICING FEES					9893,~~276~~612.0449	7369,~~477~~953.2699	~~171~~163,~~753~~566.3048
	Total Servicing Fees					9893,~~276~~612.0449	7369,~~477~~953.2699	~~171~~163,~~753~~566.3048
	Compensating Interest					(2,~~225~~115.5997)	(~~2,022~~737.9378)	(42,~~248~~853.5275)
	Delinquent Servicing Fees					0(75,167.0024)	(~~272~~52,479.0988)	(~~272~~127,647.0912)
	COLLECTED SERVICING FEES					9616,~~050~~329.4528	7116,~~182~~736.2433	~~167~~33,~~232~~065.6961
	Total Advanced Principal For Current Payment Date					018,675.0018	9215,840.0439	9234,515.0457
	Total Advanced Interest For Current Payment Date					0786,197.0024	2558,~~622~~730.3560	21,~~622~~344,927.3584
	TOTAL ADVANCES FOR CURRENT PERIOD					0804,872.0042	2574,~~714~~570.3999	21,~~714~~379,443.3941
ADDITIONAL COLLATERAL INFORMATION						GROUP 2	GROUP 1	TOTAL
	Prepayment Interest Shortfall (PPIS)					2,~~225~~115.5997	~~2,022~~737.9378	42,~~248~~853.5275
	Compensating Interest					(2,~~225~~115.5997)	(~~2,022~~737.9378)	(42,~~248~~853.5275)
	Net Prepayment Interest Shortfall (Net PPIS)					0.00	0.00	0.00
	Weighted Average Net Mortgage Rate					23.~~854147~~911841%	3.~~003094~~981451%	23.~~917868~~941612%
				Page 10 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Delinquency Report for April 26, 2004 Distribution
	Delinquency Report for September 27, 2004 Distribution
	Delinquency Report - Total
				<1 PAYMENT	1 PAYMENT	2 PAYMENTS	3+ PAYMENTS	TOTAL
DELINQUENT		Balance		-###########	~~768~~4,~~771~~205,923.3206	~~101,839.52~~-	-	~~870~~4,~~610~~205,923.8406
		% Balance		078.0015%	0.1481%	0.0200%	0.00%	0.1681%
		# Loans		-1,434	315	1-	-	415
		% # Loans		075.0099%	0.1579%	0.0500%	0.00%	0.2079%
FORECLOSURE		Balance		-	-	-	-	-
		% Balance		0.00%	0.00%	0.00%	0.00%	0.00%
		# Loans		-	-	-	-	-
		% # Loans		0.00%	0.00%	0.00%	0.00%	0.00%
BANKRUPTCY		Balance		-552,106.02	-	-	-	-552,106.02
		% Balance		0.0011%	0.00%	0.00%	0.00%	0.0011%
		# Loans		-3	-	-	-	-3
		% # Loans		0.0016%	0.00%	0.00%	0.00%	0.0016%
REO		Balance		-	-	-	-	-
		% Balance		0.00%	0.00%	0.00%	0.00%	0.00%
		# Loans		-	-	-	-	-
		% # Loans		0.00%	0.00%	0.00%	0.00%	0.00%
TOTAL		Balance		-552,106.02	~~768~~4,~~771~~205,923.3206	~~101,839.52~~-	-	~~870~~4,~~610~~758,029.8408
		% Balance		0.0011%	0.1481%	0.0200%	0.00%	0.1692%
		# Loans		-3	315	1-	-	418
		% # Loans		0.0016%	0.1579%	0.0500%	0.00%	0.2095%
Note: <1 Payment = 1-30days, 1 Payment = 31-60days, 2 Payments = 61-90days, 3+ Payments = 91+
								6 Months Moving Average
1 or 2 Payments Delinquent					3 or More Payments Delinquent
Total Foreclosure					Total Bankruptcy and REO
Note: Dates correspond to distribution dates.
				Page 11 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Delinquency Report for April 26, 2004 Distribution
	Delinquency Report for September 27, 2004 Distribution
	Delinquency Report - Group 1 Group
				<1 PAYMENT	1 PAYMENT	2 PAYMENTS	3+ PAYMENTS	TOTAL
DELINQUENT		Balance		-###########	~~768~~1,~~771~~541,467.3239	~~101,839.52~~-	-	~~870~~1,~~610~~541,467.8439
		% Balance		075.0023%	0.3370%	0.0400%	0.00%	0.3770%
		# Loans		-838	39	1-	-	49
		% # Loans		073.0096%	0.2579%	0.0800%	0.00%	0.3479%
FORECLOSURE		Balance		-	-	-	-	-
		% Balance		0.00%	0.00%	0.00%	0.00%	0.00%
		# Loans		-	-	-	-	-
		% # Loans		0.00%	0.00%	0.00%	0.00%	0.00%
BANKRUPTCY		Balance		-106,862.46	-	-	-	-106,862.46
		% Balance		0.0005%	0.00%	0.00%	0.00%	0.0005%
		# Loans		-1	-	-	-	-1
		% # Loans		0.0009%	0.00%	0.00%	0.00%	0.0009%
REO		Balance		-	-	-	-	-
		% Balance		0.00%	0.00%	0.00%	0.00%	0.00%
		# Loans		-	-	-	-	-
		% # Loans		0.00%	0.00%	0.00%	0.00%	0.00%
TOTAL		Balance		-106,862.46	~~768~~1,~~771~~541,467.3239	~~101,839.52~~-	-	~~870~~1,~~610~~648,329.8485
		% Balance		0.0005%	0.3370%	0.0400%	0.00%	0.3775%
		# Loans		-1	39	1-	-	410
		% # Loans		0.0009%	0.2579%	0.0800%	0.00%	0.3488%
Note: <1 Payment = 1-30days, 1 Payment = 31-60days, 2 Payments = 61-90days, 3+ Payments = 91+
								6 Months Moving Average
1 or 2 Payments Delinquent					3 or More Payments Delinquent
Total Foreclosure					Total Bankruptcy and REO
Note: Dates correspond to distribution dates.
				Page 12 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Delinquency Report for April 26, 2004 Distribution
	Delinquency Report for September 27, 2004 Distribution
	Delinquency Report - Group 2 Group
				<1 PAYMENT	1 PAYMENT	2 PAYMENTS	3+ PAYMENTS	TOTAL
DELINQUENT		Balance		-###########	-2,664,455.67	-	-	-2,664,455.67
		% Balance		080.0034%	0.0090%	0.00%	0.00%	0.0090%
		# Loans		-596	-6	-	-	-6
		% # Loans		079.0005%	0.0080%	0.00%	0.00%	0.0080%
FORECLOSURE		Balance		-	-	-	-	-
		% Balance		0.00%	0.00%	0.00%	0.00%	0.00%
		# Loans		-	-	-	-	-
		% # Loans		0.00%	0.00%	0.00%	0.00%	0.00%
BANKRUPTCY		Balance		-445,243.56	-	-	-	-445,243.56
		% Balance		0.0015%	0.00%	0.00%	0.00%	0.0015%
		# Loans		-2	-	-	-	-2
		% # Loans		0.0027%	0.00%	0.00%	0.00%	0.0027%
REO		Balance		-	-	-	-	-
		% Balance		0.00%	0.00%	0.00%	0.00%	0.00%
		# Loans		-	-	-	-	-
		% # Loans		0.00%	0.00%	0.00%	0.00%	0.00%
TOTAL		Balance		-445,243.56	-2,664,455.67	-	-	-3,109,699.23
		% Balance		0.0015%	0.0090%	0.00%	0.00%	01.0005%
		# Loans		-2	-6	-	-	-8
		% # Loans		0.0027%	0.0080%	0.00%	0.00%	01.0006%
Note: <1 Payment = 1-30days, 1 Payment = 31-60days, 2 Payments = 61-90days, 3+ Payments = 91+
								6 Months Moving Average
1 or 2 Payments Delinquent					3 or More Payments Delinquent
Total Foreclosure					Total Bankruptcy and REO
Note: Dates correspond to distribution dates.
				Page 13 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	REO Report for April 26, 2004 Distribution
	REO Report for September 27, 2004 Distribution
	REO Report - Mortgage Loans that Become REO During Current Distribution
SUMMARY				LOAN GROUP
Total Loan Count = 0				Loan Group 1 = Group 1; REO Book Value = 000.00
Total Original Principal Balance = 000.00				Loan Group 2 = Group 2; REO Book Value = 000.00
Total Current Balance = 000.00
REO Book Value = 000.00
REO Book Value reported corresponds to total REO loans, including loans that become REO during current distribution.
Loan Number		Original	Stated		Current	State &
&		Principal	Principal	Paid to	Note	LTV at	Original	Origination
Loan Group		Balance	Balance	Date	Rate	Origination	Term	Date
SPACE INTENTIONALLY LEFT BLANK
				Page 14 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Prepayment Report for April 26, 2004 Distribution
	Prepayment Report for September 27, 2004 Distribution
	Prepayment Report - Voluntary Prepayments
VOLUNTARY PREPAYMENTS						GROUP 2	GROUP 1	TOTAL
	Current
	Number of Paid in Full Loans					610	513	1123
	Number of Repurchased Loans					-	1-	1-
	Total Number of Loans Prepaid in Full					610	613	1223
	Paid in Full Balance					23,~~481~~997,~~883~~845.8392	12,~~142~~645,~~172~~615.6239	36,~~624~~643,~~056~~461.4531
	Repurchased Loans Balance					-	~~105,000.00~~-	~~105,000.00~~-
	Curtailments Amount					8599,~~320~~704.9412	~~132~~118,~~699~~136.2554	~~218~~217,~~020~~840.1966
	Total Prepayment Amount					24,~~567~~097,~~204~~550.7704	12,~~379~~763,~~871~~751.8793	36,~~947~~861,~~076~~301.6497
	Cumulative
	Number of Paid in Full Loans					646	562	11108
	Number of Repurchased Loans					-	1	1
	Total Number of Loans Prepaid in Full					646	663	12109
	Paid in Full Balance					217,~~481~~769,~~883~~199.8398	112,~~142~~804,~~172~~394.6294	330,~~624~~573,~~056~~594.4592
	Repurchased Loans Balance					-	105,000.00	105,000.00
	Curtailments Amount					85874,~~320~~553.9497	~~132~~862,~~699~~917.25	~~218~~1,~~020~~737,471.1922
	Total Prepayment Amount					218,~~567~~643,~~204~~753.7795	113,~~379~~772,~~871~~312.8719	332,~~947~~416,~~076~~066.6414
SPACE INTENTIONALLY LEFT BLANK
Total Prepayments by Groups (in thousands of dollars)					Total Prepayments (in thousands of dollars)
				Page 15 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Prepayment Report for April 26, 2004 Distribution
	Prepayment Report for September 27, 2004 Distribution
	Prepayment Report - Voluntary Prepayments
VOLUNTARY PREPAYMENT RATES						GROUP 2	GROUP 1	TOTAL
	SMM					01.8237%	01.5923%	01.7231%
	3 Months Avg SMM					1.16%	1.22%	1.19%
	12 Months Avg SMM
	Avg SMM Since Cut-off					01.8201%	01.5900%	01.7201%
	CPR					915.3724%	613.8285%	814.2965%
	3 Months Avg CPR					13.10%	13.65%	13.34%
	12 Months Avg CPR
	Avg CPR Since Cut-off					911.3752%	611.8238%	811.2946%
	PSA					~~2617~~1121.7899%	~~1886~~1018.49%	~~2305~~1077.3187%
	3 Months Avg PSA Approximation					1131.30%	1176.79%	1150.84%
	12 Months Avg PSA Approximation
	Avg PSA Since Cut-off Approximation					~~2617~~1342.7867%	~~1886~~1322.4956%	~~2305~~1334.3105%
	Group 1
	Group 2
CPR by Groups					Total CPR
PSA by Groups					Total PSA
				Page 16 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Prepayment Report for April 26, 2004 Distribution
	Prepayment Report for September 27, 2004 Distribution
	Prepayment Report - Voluntary Prepayments
	Group 1
	Group 2
CPR Avg since Cut-Off by Groups					Total CPR Avg since Cut-Off
PSA Avg since Cut-Off by Groups					Total PSA Avg since Cut-Off
PREPAYMENT CALCULATION METHODOLOGY
Single Monthly Mortality (SMM): (Voluntary partial and full prepayments + Repurchases)/(Beg Principal Balance - Sched Principal)
Conditional Prepayment Rate (CPR): 1-((1-SMM)^12)
PSA Standard Prepayment Model: CPR/(0.02*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/(0.02*Avg WASn,m))
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 and repurchases.
Dates correspond to distribution dates.
				Page 17 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Prepayment Detail Report for April 26, 2004 Distribution
	Prepayment Detail Report for September 27, 2004 Distribution
	Prepayment Detail Report - Loans Prepaid in Full During Current Distribution
SUMMARY						LOAN GROUP
Total Loan Count = 12						Loan Group 1 = Group 1
Total Loan Count = 23						Loan Group 1 = Group 1
Total Original Principal Balance = 3,729,056.45						Loan Group 2 = Group 2
Total Original Principal Balance = 6,654,855.63						Loan Group 2 = Group 2
Total Prepayment Amount = 3,729,056.45
Total Prepayment Amount = 6,643,461.31
Loan Number			Original			Current	State &	Type Prepayment
&		Loan	Principal	Prepayment	Prepayment	Note	LTV at	&	Origination
Loan Group		Status	Balance	Amount	Date	Rate	Origination	Original Term	Date
3275787 1			186,811.06	186,811.06	Mar-22-04	1.250%	CA - 80.00%	Paid Off - 360	Jan-09-04
3173968 1			259,404.38	259,387.55	Aug-26-04	4.131%	NJ - 79.75%	Paid Off - 360	Jan-12-04
3322616 1			123,440.56	123,440.56	Mar-07-04	4.334%	WI - 80.00%	Paid Off - 360	Jan-05-04
3273134 1			148,060.03	148,020.87	Aug-30-04	4.481%	CA - 74.95%	Paid Off - 360	Jan-23-04
3329631 1			314,050.50	314,050.50	Mar-05-04	4.634%	CA - 76.83%	Paid Off - 360	Dec-26-03
3294151 1			164,722.95	164,898.16	Aug-26-04	4.881%	OR - 75.00%	Paid Off - 360	Dec-26-03
3349585 1			275,367.73	275,367.73	Mar-14-04	4.084%	OR - 80.00%	Paid Off - 360	Jan-23-04
3306483 1			154,731.73	154,281.74	Sep-02-04	4.481%	IL - 93.94%	Paid Off - 360	Jan-14-04
3443738 1			242,502.77	242,502.77	Mar-23-04	4.234%	CA - 31.11%	Paid Off - 360	Jan-30-04
3325809 1			159,672.60	159,356.99	Aug-18-04	4.381%	CA - 48.48%	Paid Off - 360	Jan-16-04
3272469 2			566,000.00	566,000.00	Mar-29-04	1.250%	CA - 68.61%	Paid Off - 360	Feb-03-04
3340640 1			250,424.99	250,408.69	Sep-07-04	4.131%	CA - 66.05%	Paid Off - 360	Dec-31-03
3282705 2			367,156.96	367,156.96	Mar-11-04	3.734%	CA - 72.87%	Paid Off - 360	Jan-09-04
3362558 1			300,000.00	299,119.07	Aug-31-04	4.081%	CA - 80.00%	Paid Off - 360	Feb-10-04
3343915 2			355,271.54	355,271.54	Mar-15-04	4.434%	CA - 64.38%	Paid Off - 360	Jan-07-04
3366848 1			215,505.18	215,717.27	Aug-30-04	4.381%	CA - 54.00%	Paid Off - 360	Jan-12-04
3367155 2			810,638.68	810,638.68	Mar-22-04	1.250%	CA - 65.00%	Paid Off - 360	Dec-16-02
3367846 1			139,408.30	138,827.61	Sep-01-04	4.181%	AZ - 95.00%	Paid Off - 360	Jan-22-04
3370512 2			152,295.95	152,295.95	Mar-19-04	3.784%	NV - 80.00%	Paid Off - 360	Jan-28-04
3392000 1			251,422.71	249,718.38	Aug-23-04	4.481%	VA - 73.90%	Paid Off - 360	Jan-26-04
3409330 2			230,520.70	230,520.70	Mar-02-04	3.184%	CA - 75.00%	Paid Off - 360	Jan-22-04
3399006 1			240,506.86	240,333.47	Sep-13-04	4.381%	CA - 57.38%	Paid Off - 360	Jan-23-04
3391033 1			105,000.00	105,000.00	Mar-31-04	1.950%	FL - 75.00%	Repur/Subs - 360	Feb-17-04
3427246 1			220,000.00	218,659.85	Sep-15-04	4.481%	CA - 74.58%	Paid Off - 360	Feb-02-04
3429591 1			147,320.00	146,885.74	Sep-10-04	4.281%	NV - 80.00%	Paid Off - 360	Feb-04-04
3204092 2			362,916.71	362,032.36	Sep-08-04	4.481%	CA - 75.00%	Paid Off - 360	Jan-16-04
3304683 2			598,625.49	599,843.08	Aug-23-04	4.631%	GA - 79.05%	Paid Off - 360	Jan-14-04
3319899 2			397,337.67	393,842.67	Sep-07-04	4.531%	CA - 75.00%	Paid Off - 360	Jan-08-04
3336605 2			235,708.78	235,693.46	Aug-31-04	4.131%	CA - 67.50%	Paid Off - 360	Dec-31-03
3378610 2			510,000.00	510,003.29	Aug-16-04	4.831%	CA - 85.00%	Paid Off - 360	Feb-05-04
3387619 2			374,140.94	374,666.23	Aug-24-04	4.481%	CA - 75.00%	Paid Off - 360	Jan-16-04
3393057 2			644,054.40	643,452.28	Aug-27-04	4.331%	CA - 75.00%	Paid Off - 360	Jan-21-04
3408911 2			174,641.91	173,449.39	Aug-30-04	4.481%	CA - 46.67%	Paid Off - 360	Jan-23-04
3410939 2			356,000.00	355,151.95	Sep-14-04	4.381%	FL - 80.00%	Paid Off - 360	Feb-04-04
3467168 2			350,250.00	349,711.21	Aug-31-04	4.481%	CA - 75.00%	Paid Off - 360	Feb-19-04
					Page 18 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Realized Loss Report for April 26, 2004 Distribution
	Realized Loss Report for September 27, 2004 Distribution
	Realized Loss Report - Collateral
COLLATERAL REALIZED LOSSES						GROUP 2	GROUP 1	TOTAL
	Current
	Number of Loans Liquidated					-	-	-
	Collateral Realized Loss/(Gain) Amount					-	-	-
	Net Liquidation Proceeds					-	-	-
	Cumulative
	Number of Loans Liquidated					-	-	-
	Collateral Realized Loss/(Gain) Amount					-	-	-
	Net Liquidation Proceeds					-	-	-
	Note: Collateral Realized Loss Amount may include adjustments to loans liquidated in prior periods.
	Current Realized Losses							0.00
	Supplemental Losses (Recoveries)							0.00
	Current Net Realized Losses (Recoveries)							0.00
	Prior Cumulative Realized Loss							0.00
	Current Net Realized Loss (Recoveries)							0.00
	Current Cumulative Realized Loss							0.00
	Current Special Hazard Loss Coverage Amount							5,~~496~~234,~~105~~127.0048
	Current Fraud Loss Coverage Amount							16,488,317.00
	Current Bankruptcy Loss Coverage Amount							150,000.00
	Class B-1 Write Down Amount							0.00
	Class B-2 Write Down Amount							0.00
	Class B-3 Write Down Amount							0.00
	Class B-4 Write Down Amount							0.00
	Class B-5 Write Down Amount							0.00
	Class B-6 Write Down Amount							0.00
	Group 1						3 Months Moving Average
	Group 2
Collateral Loss Severity Approximation by Groups					Collateral Loss Severity Approximation
				Page 19 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Realized Loss Report for April 26, 2004 Distribution
	Realized Loss Report for September 27, 2004 Distribution
	Realized Loss Report - Collateral
DEFAULT SPEEDS						GROUP 2	GROUP 1	TOTAL
	MDR					0.00%	0.00%	0.00%
	3 Months Avg MDR					0.00%	0.00%	0.00%
	12 Months Avg MDR
	Avg MDR Since Cut-off					0.00%	0.00%	0.00%
	CDR					0.00%	0.00%	0.00%
	3 Months Avg CDR					0.00%	0.00%	0.00%
	12 Months Avg CDR
	Avg CDR Since Cut-off					0.00%	0.00%	0.00%
	SDA					0.00%	0.00%	0.00%
	3 Months Avg SDA Approximation					0.00%	0.00%	0.00%
	12 Months Avg SDA Approximation
	Avg SDA Since Cut-off Approximation					0.00%	0.00%	0.00%
	Loss Severity Approximation for Current Period
	3 Months Avg Loss Severity Approximation
	12 Months Avg Loss Severity Approximation
	Avg Loss Severity Approximation Since Cut-off
	Group 1
	Group 2
CDR by Groups					Total CDR
SDA by Groups					Total SDA
				Page 20 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Realized Loss Report for April 26, 2004 Distribution
	Realized Loss Report for September 27, 2004 Distribution
	Realized Loss Report - Collateral
	Group 1
	Group 2
CDR Avg since Cut-Off by Groups					Total CDR Avg since Cut-Off
SDA Avg since Cut-Off by Groups					Total SDA Avg since Cut-Off
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 21 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Realized Loss Detail Report for April 26, 2004 Distribution
	Realized Loss Detail Report for September 27, 2004 Distribution
	Realized Loss Detail Report - Loans Liquidated During Current Distribution
SUMMARY							LOAN GROUP
Total Loan Count Current Losses = 0
Total Loan Count Revisions = 0						Loan Group 1 = Group 1
Total Prior Principal Balance = 0.00						Loan Group 2 = Group 2
Total Current Realized Loss Amount = 0.00
Total Revisions Amount = 0.00
Total Realized Loss Amount = 0.00
Total Net Liquidation Proceeds = 0.00
Note: Total Realized Loss Amount may include adjustments to loans liquidated in prior periods.
Loan Number			Current	State &		Prior	Realized		Cumulative
&		Loan	Note	LTV at	Original	Principal	Loss/(Gain)	Realized	Realized
Loan Group		Status	Rate	Origination	Term	Balance	Revisions	Loss/(Gain)	Loss/(Gain)
SPACE INTENTIONALLY LEFT BLANK
					Page 22 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Triggers, Adj. Rate Cert. and Miscellaneous Report for April 26, 2004 Distribution
	Triggers, Adj. Rate Cert. and Miscellaneous Report for September 27, 2004 Distribution
	Triggers, Adj. Rate Cert. and Miscellaneous Report
TRIGGER EVENTS						GROUP 2	GROUP 1	TOTAL
	Has the Optional Termination Date been reached?							No
	Have the Sr. Prepay Step Down Cond been satisfied?							NoYes
	Has the Sr. Credit Supp. Depletion Date been reached?							No
	Has the Spec. Haz. Coverage Term Date been reached?							No
	Has the Fraud LossCoverage Term. Date been reached?							No
	Has the Bank LossCoverage Term. Date been reached?							No
ADJUSTABLE RATE CERTIFICATE INFORMATION						GROUP 2	GROUP 1	TOTAL
SPACE INTENTIONALLY LEFT BLANK
ADDITIONAL INFORMATION						GROUP 2	GROUP 1	TOTAL
	Current Senior Percentage					93.~~499712~~184140%	93.~~499624~~183060%	93.~~499657~~257991%
	Next Senior Percentage					0.000000%	0.000000%	0.000000%
	Current Subordinate Percentage					6.~~500288~~815860%	6.~~500376~~816940%	6.~~500343~~742009%
	Next Subordinate Percentage					0.000000%	0.000000%	0.000000%
	Current Senior Prepayment Percentage					100.000000%	100.000000%	0.000000%
	Next Projected Senior Prepayment Percentage					0.000000%	0.000000%	0.000000%
	Current Subordinated Prepayment Percentage					0.000000%	0.000000%	0.000000%
	Next Projected Subordinated Prepayment Percentage					0.000000%	0.000000%	0.000000%
								0.000000%
								0.000000%
				Page 23 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Other Related Information for April 26, 2004 Distribution
	Other Related Information for September 27, 2004 Distribution
	Other Related Information
ADDITIONAL INFORMATION						GROUP 2	GROUP 1	TOTAL
	Scheduled Principal
	1 Month Prior							~~375~~46,~~873~~906.9122
	2 Months Prior							060,166.0045
	3 Months Prior							067,577.0030
	4 Months Prior							069,663.0060
	5 Months Prior							069,784.0066
	6 Months Prior							0375,873.0091
	7 Months Prior							0.00
	8 Months Prior							0.00
	9 Months Prior							0.00
	10 Months Prior							0.00
	11 Months Prior							0.00
	12 Months Prior							0.00
	Scheduled Principal on 60+ Day Delinquent Loans
	1 Month Prior							~~(36~~0.~~24)~~00
	2 Months Prior							015.0071
	3 Months Prior							083.0036
	4 Months Prior							0.00
	5 Months Prior							0.00
	6 Months Prior							0(36.0024)
	7 Months Prior							0.00
	8 Months Prior							0.00
	9 Months Prior							0.00
	10 Months Prior							0.00
	11 Months Prior							0.00
	12 Months Prior							0.00
				Page 24 of 25				© COPYRIGHT 2004 Deutsche Bank
	IndyMac INDX Mortgage Loan Trust 2004-AR1
	Mortgage Pass-Through Certificates
	Additional Certificate Report for April 26, 2004 Distribution
	Additional Certificate Report for September 27, 2004 Distribution
	Additional Certificate Report
	CLASS	Net PPIS & Relief Act Shortfall Allocation	Unpaid Interest Amount Due	Unpaid Interest Paid	~~Net~~Remaining ~~PPIS~~Unpaid &Interest ~~Relief Act Shortfall Allocation~~Amount	~~Unpaid~~Carryover ~~Interest~~ Amount Due	~~Unpaid~~Carryover ~~Interest~~Amount Paid	Remaining ~~Unpaid~~Risk ~~Interest Amount~~Carryover
	1-A-1	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	2-A-1	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	A-X-1	0.00	0.00	0.00	0.0001	0.00	0.00	0.00
	A-X-2	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	A-R	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	B-1	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	B-2	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	B-3	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	B-4	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	B-5	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	B-6	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	P	0.00	0.00	0.00	0.00	0.00	0.00	0.00
				Page 25 of 25				© COPYRIGHT 2004 Deutsche Bank

Filing Compare · INDYMAC INDX MORTGAGE LOAN TRUST 2004-AR1