The biggest crypto exchange in the world by volume is under investigation by the US Justice Department and Internal Revenue Service

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, Bloomberg reports.

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.

While the Justice Department and IRS probe potential criminal violations, the specifics of what the agencies are examining couldn’t be determined, and not all inquiries lead to allegations of wrongdoing.

The officials involved include prosecutors within the Justice Department’s bank integrity unit, which probes complex cases targeting financial firms, and investigators from the U.S. Attorney’s Office in Seattle. The scrutiny by IRS agents goes back months, with their questions signaling that they’re reviewing both the conduct of Binance’s customers and its employees, another person said.

The U.S. Commodity Futures Trading Commission has also been investigating Binance over whether it permitted Americans to make illegal trades, Bloomberg reported in March. In that case, authorities have been examining whether Binance let investors buy derivatives that are linked to digital tokens. U.S. residents are barred from purchasing such products unless the firms offering them are registered with the CFTC.

Bitcoin losses accelerated Thursday after Bloomberg reported the investigation into Binance.