Exhibit 99.21 MBNA MASTER CREDIT CARD TRUST II SERIES 1997-C KEY PERFORMANCE FACTORS December 31, 1999 Expected B Maturity 3/15/04 Blended Coupon 6.6235% Excess Protection Level 3 Month Average 5.57% December, 1999 4.65% November, 1999 5.85% October, 1999 6.21% Cash Yield 19.14% Investor Charge Offs 5.04% Base Rate 9.45% Over 30 Day Delinquency 4.63% Seller's Interest 11.35% Total Payment Rate 14.35% Total Principal Balance $49,947,826,881.37 Investor Participation Amount $750,000,000.00 Seller Participation Amount $5,671,007,362.88