The Department of Justice is investigating the market-rattling meltdown of Bill Hwang’s Archegos Capital Management in March, a debacle that left big banks in Europe, Asia and the U.S. nursing more than US$10 billion in losses.

Federal prosecutors in Manhattan sent requests for information to at least some of the banks that dealt with the firm, according to people with knowledge of the matter, who asked not to be identified discussing the confidential probe. It’s unclear what potential violations or entities authorities are examining.

A spokesperson for prosecutors declined to comment, a spokesperson for Archegos didn’t immediately respond to a request for comment.

Banks raced to sell off Archegos’ holdings in March after the family office made massive, highly leveraged bets on companies including ViacomCBS Inc. and was unable to meet margin calls as the positions soured. The episode contributed to losses for banks including Credit Suisse Group AG, Nomura Holdings Inc. and Morgan Stanley that had helped to finance the wagers through prime brokerage units, which lend money to hedge funds and other private investment firms.

While authorities haven’t accused Archegos or its banks of breaking any laws in their dealings, the episode has drawn public criticism from regulators, as well as some inquiries behind the scenes from watchdogs around the world. The implosion shows Wall Street has grown too complacent about potential threats building up in the economy, Michael Hsu, the new acting chief of the Office of the Comptroller of the Currency, said last week.

The Securities and Exchange Commission launched a preliminary investigation into Hwang in March, a person familiar with the matter said at the time. The agency has since explored how to increase transparency for the types of derivative bets that sank the firm.

And in the U.K., the Prudential Regulation Authority has been asking firms including Credit Suisse, Nomura and UBS Group AG to hand over information related to their lending to Archegos, people familiar with the matter have said.

No bank suffered heavier losses on Archegos than Credit Suisse, and most of the leverage the bank extended was booked in London. The regulator is taking the lead on positions held by the U.K. entities of foreign banks and is coordinating with U.S., Swiss and Japanese watchdogs, the people said.

--With assistance from Christian Berthelsen and Katherine Burton.