S&P Raises, Afrms Rtgs on First Boston Mort SecCerts.

Business Editors

NEW YORK--(BUSINESS WIRE)--Standard & Poor's

July 12, 2000-- Standard & Poor's today raised its ratings on four classes of First Boston Mortgage Securities Corp. mortgage pass-through certificates (see list).

At the same time, Standard &

The raised ratings reflect actual and projected credit support percentages that are at least twice the levels required by Standard & Poor's for the higher ratings, more than seven years of seasoning and moderate losses to date.

As of the May 2000 remittance date, total delinquencies for series 1992-4 equaled 17.50%. Approximately 80% of those delinquent loans, by unpaid principal balance, however, were in the 30- to 59-day and 60- to 89-day delinquency categories. The remaining 20% were in the severely delinquent category.

Total delinquencies for series 1993-6 were only 4.36% during the same period. Cumulative losses as of May 2000 were 2.80% and 0.92% of the original pool balances of series 1992-4 and series 1993-6, respectively. Series 1992-1 had cumulative losses of 0.79% of its original pool balance for the same period.

As of the May 2000 remittance date, series 1992-1 was paid down to approximately 1.3% of its original pool balance. As of the same date, series 1992-4 and series 1993-6 were paid down to approximately 21.7% and 17.4% of their original pool balances, respectively. Series 1993-H1 was paid down to approximately 2% of its original pool balance.

Credit enhancement for series 1992-1 is provided by pool insurance. Series 1992-4 and series 1993-6 use the senior subordination structure. Credit enhancement for series 1993-H1 is provided by FHA Title I insurance, which covers up to 90% of the unpaid principal balance of the loan.

The collateral for series 1992-1, series 1992-4 and series 1993-6 consists primarily of 30-year, fixed-rate, fully amortizing, first lien mortgage loans secured by one- to four-family residential properties. The weighted average loan-to-value ratio (LTVR) at origination for series 1993-6 was greater than 90%. The weighted average LTVRs for series 1992-1 and series 1993-6 were approximately 71% and 80%, respectively. The collateral for series 1993-H1 consists of FHA title I home improvement loans, Standard & Poor's said.--CreditWire

    OUTSTANDING RATINGS RAISED

First Boston Mortgage Securities Corp.
Series     Class         Rating
                     To          From
1992-4     M         AAA         AA
1993-6     M         AAA         AA
1993-6     B-1       AAA         A
1993-6     B-2       AA+         BBB

   OUTSTANDING RATINGS AFFIRMED

First Boston Mortgage Securities Corp.
Series     Class              Rating
1992-1     1-E, 1-H, 1-M      AA-
1992-4     A-5, A-6, A-7      AAA
1993-6     A-2, A-3           AAA
1993-H1    A-IO               AA
1993-H1    B                  A