Bloomberg, citing informed sources, reported that federal prosecutors are considering the possibility of violations of Iran’s Islamic Republic sanctions by Binance Holdings, the operator of the world’s largest cryptocurrency exchange.

According to Bloomberg’s sources, the Manhattan U.S. Attorney’s Office is examining whether Binance violated sanctions by failing to prevent certain transactions on its platform and knowingly allowed those transactions to take place. A criminal division of the U.S. Department of Justice is also participating in these investigations.

Bloomberg wrote that these investigations may end without formal charges being announced, and it is not yet clear on which transactions the prosecutors are focusing.

Binance said it has a “zero tolerance” policy toward sanctions violations and cooperates with law enforcement agencies.

About three years ago, the company agreed to pay a $4.3 billion fine after it accepted that it did not comply with U.S. banking and sanctions laws.