Only a small subset of Goldman’s clients qualified to buy investments linked to crypto through the bank, said Mary Athridge, a Goldman Sachs spokeswoman. Clients had to go through a “live training” session and attest to having received warnings from Goldman about the riskiness of the assets. Only then were they allowed to put money into “third party funds” that the bank had examined first.

Morgan Stanley clients couldn’t put more than 2.5 percent of their total net worth into such investments, and investors could invest in only two crypto funds — including the Galaxy Bitcoin Fund — run by outside managers with traditional banking backgrounds.

Still, those managers may not have escaped the crypto crash. Mike Novogratz, the chief executive of Galaxy Digital and a former Goldman banker and investor, told New York magazine last month that he had taken on too much risk. Galaxy Digital Asset Management’s total assets under management, which peaked at nearly $3.5 billion in November, fell to around $2 billion by the end of May, according to a recent disclosure by the firm. Had Galaxy not sold a major chunk of Luna three months before it collapsed, Mr. Novogratz would have been in worse shape.

But while Mr. Novogratz, a billionaire, and the wealthy bank clients can easily survive their losses or were saved by strict regulations, retail investors had no such safeguards.

Jacob Willette, a 40-year-old man in Mesa, Ariz. who works as a DoorDash delivery driver, stored his entire life savings in an account with Celsius that promised high returns. At its peak, the stored value was $120,000, Mr. Willette said.

He planned to use the money to buy a house. When crypto prices started to slide, Mr. Willette looked for reassurance from Celsius executives that his money was safe. But all he found online were evasive answers from company executives as the platform struggled, eventually freezing more than $8 billion in deposits.

Celsius representatives did not respond to requests for comment.

“I trusted these people,” Mr. Willette said. “I just don’t see how what they did is not illegal.”