Fitch Upgrades 2 Classes of CSFB 1999-C1.

CHICAGO -- Fitch Ratings upgrades one class of Credit Suisse First Boston Mortgage Securities Corp.'s (CSFB) commercial mortgage pass-through certificates, series 1999-C1, as follows:

--$20.5 million class F to 'AAA' from 'AA';

Fitch has also upgrades the following class and removes from Ratings Watch Positive:

--$32.2 million class G to 'A' from 'BBB'.

In addition, Fitch affirms the following:

--$634.4 million class A-2 at 'AAA';

--Interest-only class A-X at 'AAA';

--$52.6 million class B at 'AAA';

--$58.5 million class C at 'AAA';

--$14.7 million class D at 'AAA';

--$40.9 million class E at 'AAA';

--$23.4 million class H at 'BB+';

--$11.7 million class J at 'BB-';

--$11.7 million class K at 'B-'.

Class A-1 has been paid in full. Fitch does not rate the $9.3 million class L certificates. Classes M, N, and O have been reduced to zero due to realized losses.

The rating upgrades are due to defeasance and paydown since Fitch's last ratings action. In addition, interest shortfalls incurred by class G have been recovered. The interest shortfalls were incurred partially due to fees associated with ongoing litigation with the borrower of an asset disposed of in May 2005.

Twenty-four loans (33.6%) have defeased, including the largest loan in the pool, the Exchange Apartments (5.8%). As of the January 2007 distribution date, the pool has paid down 22.2% to $909.9 million from $1.17 billion at issuance.

One loan (0.3%) is in special servicing; however, the non-rated class L is sufficient to absorb any potential losses.

Fitch continues to monitor legal fees associated with the ongoing litigation as well as the overall performance of the transaction. In addition, Fitch will revisit the ratings when the litigation is resolved.

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.