2008-08-16 00:50:04 -
- Fitch Ratings has taken various rating actions on the Alt-A RMBS transaction listed below:
--CWALT 2007-1T1
This transaction had previous rating actions published August 1, 2008.
The rating actions reflect the upgrade of 1 super-senior class which, upon a subsequent review of all super-seniors, were determined to be particularly sensitive to Fitch's cashflow assumption that the
servicer will not advance on defaulted loans in the month of liquidation. While Fitch uses a five-year mortgage default curve to assess the risk of a bond default for Alt-A super-seniors, shortfalls from liquidations without servicer advancing were projected to result in unrecovered principal under an 'AAA' stress at deal maturity for some super-senior classes despite having maintained credit protection at the end of the stressed five-year mortgage default period. Today's rating revision considers the class's sensitivity to that particular cashflow assumption. The super-senior class upgraded reverted to the initial 'AAA' rating. Additionally, one non-super senior class was downgraded to a level consistent with all other non-super senior classes with similar credit enhancement.
A spreadsheet detailing Fitch's rating actions on the transactions in question is available on the Fitch Ratings web site at www.fitchratings.com under the following headers:
Structured Finance then RMBS then Research Highlights then
The rating actions taken today reflect Fitch's analysis of expected default and loss from delinquent loans, in addition to projected losses from the currently performing pool. Fitch generates its expectations using its ResiLogic default and loss model. These expectations are adjusted based on actual performance to-date versus model projected performance. The model incorporates the impact of historical home price movements on mortgage performance, in addition to projecting further stress for many regions of the U.S. The model also reflects the demonstrated high default rates for loans that exhibit risk-layering.
Fitch is nearing completion of its review of the 2005-2007 Alt-A transactions. This review was completed in two separate phases. The first phase reviewed all mezzanine and subordinated bonds. The second phase, which is nearly completed, reviewed the senior bonds that, in many instances, required additional cash flow analysis to evaluate the risk of the various individual classes within the senior tranche. Most notably, the use of super-senior structures was considered in evaluating senior bonds.
Additional details are available in the following reports, also available at www.fitchratings.com under:
Structured Finance then RMBS then Special Reports
--'U.S. RMBS Alt-A Surveillance Criteria for Recent Vintages' (May 29, 2008):
--'Drivers of 2006-2007 Alt-A Collateral Performance' (May 7, 2008);
--'U.S. Alt-A RMBS Performance Deteriorating Rapidly, Fitch Initiates Extensive' (Mar. 6, 2008);
--'Alt A Bonds Placed on Rating Watch Negative - Amended' (Mar. 20, 2008).
Further information regarding current delinquency, loss, and credit enhancement statistics is also available at www.fitchratings.com.
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.
Fitch Ratings, New York
Tara Sweeney, 212-908-0347
Michele Patterson, 212-908-0779
Media Relations:
Sandro Scenga, 212-908-0278
