DBRS Rates Credit Suisse First Boston Mortgage Securities Corp., CSMC Series 2010-1R

DBRS has today assigned the following ratings to the Credit Suisse First Boston Mortgage Securities Corp., CSMC Series 2010-1R Notes issued by CSMC Series 2010-1R (the Trust).

-- $23.3 million Class 1-A-1 rated at AAA
-- $18.6 million Class 8-A-1 rated at AAA
-- $11.2 million Class 13-A-1 rated at AAA
-- $7.7 million Class 14-A-1 rated at AAA
-- $5.8 million Class 15-A-1 rated at AAA
-- $3.3 million Class 19-A-1 rated at AAA
-- $112.2 million Class 25-A-1 rated at AAA
-- $27.7 million Class 26-A-1 rated at AAA
-- $34.0 million Class 28-A-1 rated at AAA
-- $17.2 million Class 31-A-1 rated at AAA
-- $12.6 million Class 32-A-1 rated at AAA
-- $6.9 million Class 34-A-1 rated at AAA
-- $9.1 million Class 38-A-1 rated at AAA
-- $8.8 million Class 39-A-1 rated at AAA
-- $4.9 million Class 40-A-1 rated at AAA
-- $7.0 million Class 45-A-1 rated at AAA
-- $7.4 million Class 46-A-1 rated at AAA
-- $22.2 million Class 51-A-1 rated at AAA

There are a total of 51 groups in this resecuritization trust. DBRS rates bonds from eighteen groups, each consisting of one to three seasoned senior residential mortgage-backed securities (RMBS). Within the DBRS-rated groups, the AAA ratings on the notes reflect the credit enhancement provided by subordination. The ratings also reflect the quality of the underlying securities.

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

Interest and principal payments on the notes will be made generally on the second business day following the 25th day of each month commencing in February 2010. Within each group, interest and then principal will be distributed on a sequential basis to the notes, in the order of priority specified in the private placement memorandum, until the principal balances thereof are reduced to zero. Groups 32 and 51 are Turbo Note Groups and excess interest for these groups will be distributed as principal to the notes on a sequential basis until the principal balances thereof are reduced to zero.

Any losses realized from the underlying securities will first be allocated to the Owner Trust Certificate and then, within each group, will be allocated in a reverse sequential order to the notes.

The Trust is a resecuritization consisting of fifty-four senior RMBS, represented by various real estate mortgage investment conduits (REMICs). Within the DBRS-rated groups, the REMICs are backed by pools of prime and Alt-A, fixed- and adjustable-rate, first-lien, one- to four-family residential mortgages.

Notes:
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.