Exhibit 99.41 MBNA MASTER CREDIT CARD TRUST II SERIES 1999-B KEY PERFORMANCE FACTORS July 31, 1999 Expected B Maturity 3/16/2009 Blended Coupon 5.9788% Excess Protection Level 3 Month Average 6.13% July, 1999 6.11% June, 1999 5.07% May, 1999 7.20% Cash Yield18.70% Investor Charge Offs 4.97% Base Rate 7.62% 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$750,000,000.00 Seller Participation Amount$4,456,383,517.80