As part of the inquiry, officials who probe money laundering and tax offenses have sought information from individuals with insight into Binance's business, according to people with knowledge of the matter who asked not to be named because the probe is confidential. Led by Changpeng Zhao, a charismatic tech executive who relishes promoting tokens on Twitter and in media interviews, Binance has leap-frogged rivals since he co-founded it in 2017.

The firm, like the industry it operates in, has succeeded largely outside the scope of government oversight. Binance is incorporated in the Cayman Islands and has an office in Singapore but says it lacks a single corporate headquarters. Chainalysis Inc., a blockchain forensics firm whose clients include U.S. federal agencies, concluded last year that among transactions that it examined, more funds tied to criminal activity flowed through Binance than any other crypto exchange.