Jamie Dimon has made no secret of his skepticism about bitcoin, but he has given the technology behind it the sincerest form of praise: investment.

Under his leadership, New York-based JPMorgan Chase developed a variant of blockchain — a secure ledger with worldwide accessibility that has been used to generate cryptocurrency — then leveraged it to create not only the Interbank Information Network, a data-transfer service that can speed up payments, but its own digital coin.