In terms of total world trade turnover, China UnionPay is the leader in debt cards, with over $5.3 trillion in payments, or about 47 percent of the market share, whereas Visa has 40.6 percent, and MasterCard only 12.2 percent, according to the Nilson Report.

In overall transactions, Visa is still the leader with $4.6 trillion, and China UnionPay comes in second with $2.5 trillion in transactions in the first half of last year.