Cryptocurrency exchange Binance is being investigated by the Commodity Futures Trading Commission to determine if U.S. residents traded derivatives on it in violation of U.S. rules, Bloomberg reported.

Binance hasn’t been accused of any wrongdoing and the CFTC may not bring an enforcement action, according to the report, which cited people familiar with the matter. Bloomberg also did not outline a time period for this alleged trading.

Spokespeople for Binance and the CFTC did not immediately return requests for comment. However, in a tweet posted after Bloomberg’s report ran, the exchange’s founder and CEO, Changpeng Zhao, appeared to call the report “FUD,” using an acronym for “fear, uncertainty and doubt” that is often used to refer to unwelcome news in the crypto industry.

The news comes a day after Binance announced it has hired former U.S. Senator and Ambassador to China Max Baucus as a policy adviser who would be able to navigate the exchange’s relationship with U.S. regulators. Baucus currently operates a consulting business.

Binance does not directly serve U.S. customers on paper, instead using a San Francisco entity operating as Binance.US for that purpose. Despite this, the parent exchange has announced at least twice in two years that it would be removing all U.S. customers from its platform.

The probe is another sign that regulators are trying to funnel U.S. investors into regulated channels.

Derivatives trading in the U.S. is strictly overseen by the CFTC. The agency brought an enforcement action last year against BitMEX, also on allegations that it allowed U.S. customers to trade derivatives products. That case, which is also being pursued by the Department of Justice, is ongoing.

UPDATE (March 12, 2021, 14:00 UTC): Updated with additional context throughout.