Fitch Rates IndyMac ABS Home Equity Mtge Loan A-B Trust, SPMD 2004-B.

NEW YORK -- IndyMac Home Equity Mortgage Loan Asset-Backed Trust, series SPMD 2004-B is rated by Fitch Ratings as follows:

-- $817.5 million class A-I, A-II-1, A-II-2, A-II-3 certificates 'AAA';

-- $27.5 million class M-1 certificates 'AA';

-- $28 million class M-2 certificates 'AA';

-- $16 million class M-3 certificates 'AA';

-- $14.5 million class M-4 certificates 'A';

-- $14.5 million class M-5 certificates 'A';

-- $15 million class M-6 certificates 'A';

-- $13 million class M-7 certificates 'BBB+';

-- $10.5 million class M-8 certificates 'BBB';

-- $10 million class M-9 certificates 'BBB-';

-- $2.5 million class M-10 certificates 'BBB-'.

Credit enhancement for the 'AAA' rated class A certificates reflects the 15.15% subordination provided by classes M-1, M-2, M-3, M-4, M-5, M-6, M-7, M-8, M-9, M-10, monthly excess interest, and initial overcollateralization (OC) of 3.10%. Credit enhancement for the 'AA' rated class M-1 certificates reflects the 12.40% subordination provided by classes M-2, M-3, M-4, M-5, M-6, M-7, M-8, M-9, M-10, monthly excess interest, and initial OC. Credit enhancement for the 'AA' rated class M-2 certificates reflects the 9.60% subordination provided by classes M-3, M-4, M-5, M-6, M-7, M-8, M-9, M-10 monthly excess interest, and initial OC. Credit enhancement for the 'AA' rated class M-3 certificates reflects the 8% subordination provided by classes M-4, M-5, M-6, M-7, M-8, M-9, M-10, monthly excess interest, and initial OC. Credit enhancement for the 'A' rated class M-4 certificates reflects the 6.55% subordination provided by classes M-5, M-6, M-7, M-8, M-9, M-10, monthly excess interest, and initial OC. Credit enhancement for the 'A' rated class M-5 certificates reflects the 5.10% subordination provided by classes M-6, M-7, M-8, M-9, M-10, monthly excess interest, and initial OC. Credit enhancement for the 'A' rated class M-6 certificates reflects the 3.60% subordination provided by class M-7, M-8, M-9, M-10, monthly excess interest, and initial OC.

Credit enhancement for the 'BBB+' rated class M-7 certificates reflects the 2.30% subordination provided by class M-8, M-9, M-10, monthly excess interest, and initial OC. Credit enhancement for the 'BBB' rated class M-8 certificates reflects the 1.25% subordination provided by classes M-9, M-10, monthly excess interest, and initial OC. Credit enhancement for the 'BBB-' rated class M-9 certificates reflects the 0.25% subordination provided by class M-10, monthly excess interest, and initial OC. Credit enhancement for the 'BBB-' rated class M-10 certificates reflects monthly excess interest and initial OC. In addition, the ratings reflect the integrity of the transaction's legal structure, as well as the capabilities of IndyMac Bank, F.S.B. as master servicer. Deutsche Bank National Trust Company will act as trustee.

On the closing date, the depositor will place approximately $102,522,657, which will be held by the trustee in a prefunding account relating to mortgage loans in group I and approximately $47,477,343 relating to the mortgage loans in group II. The amount on deposit in each account will be used to purchase subsequent mortgage loans during the period from the closing date up to and including Oct. 30, 2004.

The certificates are supported by two groups of mortgage loans. The group 1 mortgage pool consists of first lien fixed-rate and adjustable-rate mortgage loans with a statistical date pool balance of $487,672,348. Approximately 23.24% of the group 1 mortgage loans are fixed-rate mortgage loans and approximately 76.76% of the group 1 mortgage loans are adjustable-rate mortgage loans. The weighted average loan rate is approximately 7.353%. The weighted average remaining term to maturity is 355 months. The average principal balance of the loans is approximately $164,089. The weighted average original loan-to-value ratio is 76.93%, and the weighted average FICO score is 598. The properties are primarily located in California (20.24%), New York (10.51%), and New Jersey (8.13%).

The group 2 mortgage pool consists of first lien fixed-rate and adjustable-rate mortgage loans with a statistical date pool balance of $220,449,112. Approximately 21.70% of the group 2 mortgage loans are fixed-rate mortgage loans and approximately 78.30% of the group 2 mortgage loans are adjustable-rate mortgage loans. The weighted average loan rate is approximately 6.888%. The weighted average remaining term to maturity is 359 months. The average principal balance of the loans is approximately $395,070. The weighted average original loan-to-value ratio is 76.48%, and the weighted average FICO is 625. The properties are primarily located in California (44.26%), New York (10.75%), and New Jersey (6.56%).

IndyMac ABS, Inc., the depositor, purchased the mortgage loans from IndyMac Bank, F.S.B., the mortgage loan seller, and caused the mortgage loans to be assigned to the trustee for the benefit of holders of the certificates. For federal income tax purposes, an election will be made to treat the trust fund as multiple real estate mortgage investment conduits (REMICs).