Fitch Rates $516.2MM Morgan Stanley Mortgage Loan Trust Mtge P-T Cfts, Series 2007-12

NEW YORK--(BUSINESS WIRE)--Fitch rates Morgan Stanley Mortgage Loan Trust mortgage pass-through certificates, Series 2007-12 as follows:

-$497.6 million classes 1-A-1, 1-A-2, 1-A-3, 1-A-P, 2-A-1, 2-A-2, 2-A-3, 2-A-X, 3-A-1 through 3-A-42, 3-A-P, 4-A-1 through 4-A-5, 4-A-X, and A-R 'AAA'

The 'AAA' rating on the senior certificates reflects the 3.60% total credit enhancement provided by the 1.75% class B1, the 0.65% class B2, the 0.30% class B3, the privately offered 0.30% class B4, the privately offered 0.35% class B5 and the privately offered 0.25% class B6. The subordinate certificates, classes B1 through B6, are not rated by Fitch.

Fitch believes that the amount of credit enhancement will be sufficient to cover credit losses, including limited bankruptcy, fraud and special hazard losses. In addition, the ratings reflect the quality of the mortgage collateral, the strength of the legal and financial structures, the master servicing capabilities of Wells Fargo Bank, National Association (rated 'RMS1' by Fitch).

This transaction contains certain classes designated as exchangeable certificates and others as regular certificates. Classes 1-A-2, 1-A-3, 2-A-2, 2-A-3, 3-A-9, 3-A-14, 3-A-15, 3-A-19 through 3-A-42, and the 4-A-3 through 4-A-5 are the exchangeable certificates. Classes 1-A-1, 2-A-1, 3-A-7, 3-A-8, 3-A-11, 3-A-12, 3-A-13, 3-A-16, 3-A-17, 3-A-18, and 4-A-1 are the depositable certificates.

All or a portion of certain classes of offered certificates may be exchanged for a proportionate interest in the related exchangeable certificates. All or a portion of the exchangeable certificates may also be exchanged for the related offered certificates in the same manner. This process may occur repeatedly. The classes of offered certificates and of exchangeable certificates that are outstanding at any given time, and the outstanding principal balances and notional amounts of these classes, will depend upon any related distributions of principal, as well as any exchanges that occur. Offered certificates and exchangeable certificates in any combination may be exchanged only in the proportions shown in the governing documents. Holders of exchangeable certificates will be the beneficial owners of a proportionate interest in the certificates in the related combination group and will receive a proportionate share of the distributions on those certificates.

On each distribution date when exchangeable certificates are outstanding, principal distributions from the applicable related certificates are allocated to the related exchangeable certificates that are entitled to principal. The payment characteristics of the classes of exchangeable certificates will reflect the payment characteristics of their related classes of regular certificates.

The aggregate mortgage pool trust consists of 819 fixed-rate, conventional, first lien residential mortgage loans, substantially all of which have original terms to stated maturity of 30 years. As of the cut-off date (July 1, 2007), the mortgages have an aggregate principal balance of approximately $516,179,002. The mortgage pool has a weighted average original loan-to-value ratio (OLTV) of 69.18%, a weighted average coupon (WAC) of 6.414%, and a weighted average remaining term (WAM) of 343 months.

None of the mortgage loans are 'high cost' loans as defined under any local, state or federal laws. For additional information on Fitch's rating criteria regarding predatory lending legislation, please see the press release issued May 1, 2003 entitled 'Fitch Revises Rating Criteria in Wake of Predatory Lending Legislation' available on the Fitch Ratings web site at www.fitchratings.com.

The mortgage loans were primarily originated or acquired by Morgan Stanley Credit Corporation, GreenPoint Mortgage Funding, Inc., and IndyMac Bank, FSB.

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