Exhibit 99.21 MBNA MASTER CREDIT CARD TRUST II SERIES 1996-L KEY PERFORMANCE FACTORS JULY, 1999 Expected B Maturity 12/15/99 Blended Coupon 5.0937% Excess Protection Level 3 Month Average 6.44% July, 1999 6.37% June, 1999 5.31% May, 1999 7.64% Cash Yield 18.74% Investor Charge Offs 4.97% Base Rate 7.40% Over 30 Day Delinquency 4.84% Seller's Interest 9.75% Total Payment Rate 14.54% Total Principal Balance $ 45,698,903,036.29 Investor Participation Amount $ 500,000,000.00 Seller Participation Amount $ 4,456,383,517.80