Exhibit 99.42 MBNA MASTER CREDIT CARD TRUST II SERIES 1999-D KEY PERFORMANCE FACTORS July 31, 1999 Expected B Maturity 6/15/2006 Blended Coupon 5.5733% Excess Protection Level 3 Month Average 4.96% July, 1999 5.85% June, 1999 4.07% May, 1999 N/A Cash Yield18.70% Investor Charge Offs 4.97% Base Rate 7.88% Over 30 Day Delinquency 4.84% Seller's Interest 9.75% Total Payment Rate14.54% Total Principal Balance$45,698,903,036.29 Investor Participation Amount$500,000,000.00 Seller Participation Amount$4,456,383,517.80