Fitch Downgrades 2 Classes of CSFB, Series 1999-C1.

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

-- $11.7 million class J to 'B+' from 'BB-';

-- $11.7 million class K to 'B-' from 'B' and removed from Rating Watch Negative.

In addition, Fitch affirms the following classes:

-- $79.4 million class A-1 'AAA';

-- $660.5 million class A-2 'AAA';

-- Interest-only class A-X 'AAA';

-- $52.6 million class B 'AA';

-- $58.5 million class C 'A';

-- $14.7 million class D 'A-';

-- $40.9 million class E 'BBB';

-- $20.5 million class F 'BBB-';

-- $32.2 million class G 'BB+';

-- $23.4 million class H 'BB'.

The $2 million class N certificates remain at 'C'. Fitch does not rate the $15.8 million class L, the $9.3 million class M, or class O, which has been reduced to zero due to realized losses.

The downgrades reflect the expected losses on the specially serviced loans. As of the March 2005 distribution date, the pool has paid down 11.7% to $1.03 billion from $1.17 billion at issuance.

Six assets (6.4%) are currently in special servicing: three real estate owned (REO) properties (6%); one loan that is 90+ days delinquent (0.1%); one loan that is 30 days delinquent (0.1%); and one loan that is current (0.2%). The largest REO property (3.1%) is an office located in Canton, MA. The property is being marketed for sale and current offers, as well as the October 2004 appraisal, indicate sizable losses are likely. The second largest REO property (2.4%) is an offsite airport parking facility located in Edmundson, MO. The property is expected to be sold as part of a portfolio, with the allocation toward this property expected to result in losses. Losses are also expected on the third largest REO property (0.4%); however, no losses are expected on the remaining three specially serviced loans (0.4%) at this time.

The Binnings Building loan, which was specially serviced and represented 0.6% of the pool, paid off in full in March 2005. Yield maintenance, default interest, and late charges, however, were waived as a condition of the payoff.

In addition to the specially serviced loans mentioned above, 33 loans (24.3%) are considered Fitch loans of concern due to decreases in DSCR and occupancy or other performance issues. These loans' higher likelihood of default was incorporated into Fitch's analysis. The largest of these loans is the Tallahassee Mall loan (4.4%), secured by a mall in Tallahassee, FL, which has seen a drop in net cash flow since issuance due to an increase in operating expenses.