DBRS Rates Credit Suisse First Boston Mortgage Securities Corp., CSMC Series 2009-2R

DBRS has today assigned the following ratings to the Credit Suisse First Boston Mortgage Securities Corp. (CSMC) Series 2009-2R certificates issued by CSMC Series 2009-2R (the Trust).

• $30.0 million Class 2-A-1* rated at AAA
• $3.3 million Class 2-A-2* rated at AAA
• $3.3 million Class 2-A-3* rated at AAA
• $36.7 million Class 2-A-5** rated at AAA
• $33.4 million Class 2-A-6** rated at AAA
• $50 Class 2-R rated at AAA

DBRS rates the Group 2 certificates in this resecuritization trust. The AAA ratings on the Class 2-A-1, 2-A-2, 2-A-3 certificates reflect the 45% of credit enhancement provided by subordination. The ratings also reflect the quality of the underlying asset, which is a super senior residential mortgage pass-through certificate. The Class 2-A-1, 2-A-2 and 2-A-3 certificates (Exchangeable REMIC Certificates) are exchangeable for certain other classes of certificates (Exchangeable Certificates) and vice versa, in the combinations described in Annex II of the offering memorandum.

DBRS does not rate the Class 2-A-4, 2-A-7 and 2-A-8 certificates or any certificates in Group 1 and Groups 3 through 10.

Interest and principal payments on the Group 2 certificates will be made generally on the 26th day of each month commencing in May 2009. Interest payments will be distributed on a pro rata basis to the certificates. Principal will be distributed on a sequential basis to the certificates, in numerical order, until the certificate principal balances thereof are reduced to zero.

Any losses realized from the Group 2 underlying securities will be allocated in a reverse numerical order to the certificates.

The Trust is a resecuritization of a residential mortgage pass-through certificate, WaMu Asset Acceptance Corp., 2007-HY6 Class 1-A1, which is backed by a pool of primarily Alt-A adjustable-rate mortgages secured by first liens on one- to four-family properties.

Notes:

• Denotes Exchangeable REMIC Certificate.
  ** Denotes Exchangeable Certificate.

All figures are in U.S. dollars unless otherwise noted.

The applicable methodology is Rating U.S. Residential Mortgage-Backed Securities Transactions, which can be found on our website under Methodologies.

This is a Structured Finance rating.