NEW YORK (Standard&Poor's CreditWire) April 22, 1999--Standard&Poor's today assigned its preliminary ratings to American Express Credit Account Master Trust Series 1999-1 as follows: -- $865 million class A 5.6% asset-backed certificates at triple-'A'; -- $60 million class B 5.85% asset-backed certificates at single-'A'; -- $75 million collateral interest at NR. The preliminary ratings reflect: -- Credit enhancement levels of 13.5% for class A and 7.5% for class B; -- Strong historical portfolio performance; and -- Structural considerations, including subordination of interest payable to the collateral interest holders. Standard&Poor's ratings address the timely payment of interest on the fifteenth of each month on class A and class B and the ultimate payment of principal by