They are profitable for a few years now, afaik visa/master pays you a share of their profit each time customer makes a transaction(i.e. share of merchant fee).

They are profitable for a few years now, afaik visa/master pays you a share of their profit each time customer makes a transaction(i.e. share of merchant fee). There are also credits, loans, exchange fees, subscription fees i.e. a lot products that make them money.