Visa and Mastercard combined represent 83% of the number of credit cards in circulation, and 100% of the number of debit cards in circulation. That last one, t

Visa and Mastercard combined represent 83% of the number of credit cards in circulation, and 100% of the number of debit cards in circulation. That last one, too, is probably a big part of the reason for the classification. There are more Visa/MC debit cards out there than their are credit cards.