DBRS Rates Credit Suisse First Boston Mortgage Securities Corp., CSMC Series 2010-12R

DBRS has today assigned the following ratings to the Credit Suisse First Boston Mortgage Securities Corp., CSMC Series 2010-12R Securities issued by CSMC Series 2010-12R (the Trust).

-- $83.3 million Class 3-A-1 rated at AAA
-- $8.8 million Class 11-A-1 rated at AAA
-- $50.9 million Class 13-A-1 rated at AAA
-- $24.0 million Class 14-A-1 rated at AAA
-- $6.4 million Class 15-A-1 rated at AAA

There are a total of 15 groups in this resecuritization trust. DBRS rates five groups, each backed by one seasoned senior residential mortgage-backed security (RMBS). The AAA ratings on the Class A-1 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 securities will generally be made one business day following the underlying distribution date (the 25th of each month), commencing in June 2010. 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.

Any losses realized from the underlying securities will be allocated in a reverse sequential order to the notes.

This Trust is a resecuritization consisting of five seasoned senior RMBS, represented by various real estate mortgage investment conduits (REMICs). 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.