Exhibit 99.21 MBNA MASTER CREDIT CARD TRUST II SERIES 1996-L KEY PERFORMANCE FACTORS SEPTEMBER, 1998 Expected B Maturity 12/15/99 Blended Coupon 5.7629% Excess Protection Level 3 Month Average 5.40% September, 1998 4.44% August, 1998 6.39% July, 1998 5.36% Cash Yield 17.38% Investor Charge Offs 5.18% Base Rate 7.76% Over 35 Day Delinquency 5.04% Seller's Interest 13.10% Total Payment Rate 13.10% Total Principal Balance $ 39,849,511,082.92 Investor Participation Amount $ 500,000,000.00 Seller Participation Amount $ 5,219,716,564.43