Fitch Downgrades 2 RMBS Classes from 2 Ameriquest NIM Trusts

NEW YORK--(BUSINESS WIRE)--Fitch Ratings has taken the following rating actions on the two Ameriquest Net Interest Margin (NIM) Trusts listed below:

Series 2005-RN4:

--$7.4 million class A downgraded to 'BBB' from 'AAA'.

Underlying Transaction: Ameriquest Mortgage Securities Inc., series 2005-R4

Series 2005-RN5:

--$503,000 class A downgraded to 'BBB' from 'AAA'.

Underlying Transaction: Ameriquest Mortgage Securities Inc., series 2005-R5

Both classes listed above have a financial guarantee provided by Radian Guaranty Inc. (not rated by Fitch) and backup guarantee Financial Guaranty Insurance Company (IFS rated 'BBB' by Fitch).

The rating actions reflect actual pay-down performance of the NIM securities to date compared to initial projections, as well as, changes that Fitch previously made to its subprime loss forecasting assumptions for the underlying transactions.

Additional details are available in the following research, available at www.fitchratings.com

--'Fitch Places $139B U.S. Subprime RMBS On Watch Negative on Worsening Mortgage Performance' (Feb. 1, 2008);

--'U.S. Subprime RMBS/HEL Upgrade/Downgrade Criteria' (June 12, 2007);

--'Downgrade Criteria for Recent Vintage U.S. Subprime RMBS' (Aug. 8, 2007)

--'U.S. Rating Criteria for Net Interest Margin Securitizations: Updated' (Feb. 6, 2007).

All of Fitch's ratings criteria for US subprime RMBS are also available at www.fitchratings.com/subprime.

Fitch's rating definitions and the terms of use of such ratings are available on the agency's public site, www.fitchratings.com. Published ratings, criteria and methodologies are available from this site, at all times. Fitch's code of conduct, confidentiality, conflicts of interest, affiliate firewall, compliance and other relevant policies and procedures are also available from the 'Code of Conduct' section of this site.