Exhibit 99.40 MBNA MASTER CREDIT CARD TRUST II SERIES 1999-A KEY PERFORMANCE FACTORS August 31, 1999 Expected B Maturity 2/17/2004 Blended Coupon 5.5191% Excess Protection Level 3 Month Average 5.66% August, 1999 5.91% July, 1999 5.96% June, 1999 5.11% Cash Yield18.20% Investor Charge Offs 4.78% Base Rate 7.52% Over 30 Day Delinquency 4.81% Seller's Interest 7.19% Total Payment Rate14.37% Total Principal Balance$46,158,397,644.87 Investor Participation Amount$500,000,000.00 Seller Participation Amount$3,316,578,126.38