$95 Million

The collapse of a little-known company that operated banking software for fast-growing online start-ups has claimed tens of thousands of unsuspecting victims — depositors in the start-ups whose accounts are frozen.

About $300 million in deposits have been affected, though some of that money has already been released to customers, according to filings in the bankruptcy case involving the software company, Synapse Financial Technologies. But Synapse’s court-appointed trustee has said there is as much as a $95 million “shortfall” in the funds that Synapse handled for lenders.

Deposits of up to $250,000 are typically insured by the Federal Deposit Insurance Corporation. So even if the bank fails, you can access your money.

But the problem is that these online lenders are technically not banks. They simply collect your money and pass it along to actual banks using intermediaries like Synapse.

“It’s really unprecedented,” said Jason Mikula, a former Goldman Sachs product manager who now writes a financial newsletter. “There is no direct, legal authority for the F.D.I.C. or any other agency to intervene.”

The start-ups, including the companies Juno, Yotta and Yieldstreet, have the backing of Silicon Valley venture capitalists. Account holders at these companies did not know about Synapse, which said it had around $2 million of cash on hand when it filed for bankruptcy.

“I didn’t play with this money,” said Mark Hingle, 33, a paramedic in Louisiana who has $60,000 frozen. “I thought this was a bank that was F.D.I.C. insured.”