Exhibit 99.21 MBNA MASTER CREDIT CARD TRUST II SERIES 1996-L KEY PERFORMANCE FACTORS JUNE, 1999 Expected B Maturity 12/15/99 Blended Coupon 5.0774% Excess Protection Level 3 Month Average 6.07% June, 1999 5.31% May, 1999 7.64% April, 1999 5.24% Cash Yield 17.46% Investor Charge Offs 5.06% Base Rate 7.08% Over 30 Day Delinquency 4.82% Seller's Interest 11.01% Total Payment Rate 13.71% Total Principal Balance $ 44,380,968,357.42 Investor Participation Amount $ 500,000,000.00 Seller Participation Amount $ 4,888,448,838.93