S&P Global Ratings assigned its preliminary 'AAA (sf)' rating to BA Credit Card Trust's (BACCT) $500 million class A(2021-1) BAseries notes. The preliminary rating reflects: The 31.75% credit support that the outstanding class B and C notes, as well as the class D certificate, provide. However, we only consider 21.25% as available to the class A notes under our 'AAA' stress scenario because we assume the class D certificate (10.50% credit support) is completely written down. We believe that the 21.25% available credit support is sufficient to withstand the simultaneous stresses we apply to our 6.5% base-case loss rate, 13.0% base-case payment rate, 15.0% base-case yield, and 3.0% purchase rate assumptions for the notes. In addition, we used stressed excess