Here’s a ‘Master Charge’ card from up in the rafters in my home’s garage here in Seattle, found during a clean-up effort. This is the forerunner to what later became the ubiquitous Mastercard.
The original Interbank/ Master Charge card was created by several California banks as a competitor to the BankAmericard issued by Bank of America (later to became the Visa credit card issued by Visa Inc.).
So how many Mastercards are in peoples’ wallets all around the world? It’s actually very hard to pin the number down. Banks issue and manage their individually branded cards while using the MasterCard company only as a “switch” to process transactions. Also : depending on the country, MasterCard might not ‘see’ any transactions on a MasterCard branded card. Quite a few countries require that national credit card network (not MasterCard) process domestic transactions, leaving only international transactions to be processed by MasterCard.