DBRS Rates Credit Suisse First Boston Mortgage Securities Corp., CSMC Series 2009-8R

DBRS has today assigned the following ratings to the Credit Suisse First Boston Mortgage Securities Corp., CSMC Series 2009-8R Certificates issued by CSMC Series 2009-8R (the Trust).

-- $50.2 million Class 5-A-1* rated at AAA
-- $35.9 million Class 5-A-3** rated at AAA
-- $7.2 million Class 5-A-4** rated at AAA
-- $7.2 million Class 5-A-5** rated at AAA
-- $43.0 million Class 5-A-8* rated at AAA
-- $50 Class 5-R rated at AAA

DBRS rates Group 5 in this resecuritization trust, which consists of one seasoned senior residential mortgage-backed security (RMBS). Within Group 5, the AAA ratings reflect the credit enhancement provided by subordination. The ratings also reflect the quality of the underlying securities. Certain classes of 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 private placement memorandum.

Other than the specified classes above, DBRS does not rate any other certificates in this transaction.

Interest and principal payments on the certificates will be made generally on the 26th day of each month commencing in July 2009. Interest payments will be distributed on a pro rata basis to the certificates, and principal will be distributed on a sequential basis to the certificates, in the order of priority specified in the private placement memorandum, until the certificate principal balances thereof are reduced to zero.

Any losses realized from the underlying securities within each group will be allocated in a reverse numerical order to the certificates.

The Trust is a resecuritization consisting of eight senior RMBS, represented by various real estate mortgage investment conduits (REMICs). The REMICs are backed by pools of first-lien one- to four-family residential mortgages.

Notes:

• Denotes Exchangeable Certificate.
  ** Denotes Exchangeable REMIC 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.