BIN sponsorship is the arrangement under which a bank or other licensed institution that is a principal member of a card network allows a company without that membership, typically a fintech, neobank or expense-management platform, to issue cards using the bank's network membership and bank identification number (BIN) ranges. The bank stays the legal issuer and answers to the network and its regulators, while the sponsored company designs and markets the cards.
The term describes the relationship; the bank on the other side of it is the BIN sponsor, and that entry explains the parties, economics and compliance duties in full. In practice the sponsor is often the same institution described as a sponsor bank, and the sponsored company usually acts as the program manager.
BIN sponsorship is narrower than banking-as-a-service, which can also cover accounts, deposits and payments. On the acquiring side, a similar sponsorship lets a payment facilitator board merchants under an acquirer's membership, but that is not usually called BIN sponsorship.