American Express, Diners Club/Discover, JCB, Mastercard, UnionPay, and Visa general purpose credit, debit, and prepaid cards collectively generated purchase volume (spending for goods and services) of $20.60 trillion in 2016. These global brand cards are projected to generate $52.39 trillion by 2026. Projections include card-present and card-not-present payments generated by credit, debit, and prepaid cards as well as QR codes on mobile phones. Not included here are figures from more than 75 domestic-market-only general purpose card brands that function within single countries. They include El...