South Korean authorities are recommending illegal gambling charges be filed against the CoinOne cryptocurrency exchange for its margin trading service.

In January, the Gyeonggi Nambu Provincial Police Agency announced that it was conducting an investigation into CoinOne’s margin trading service, which allowed customers to speculate on whether the value of a particular cryptocurrency would rise or fall.

On Thursday, Yonhap News reported that the Gyeonggi Nambu investigators had recommended bringing charges of illegal gambling against three CoinOne execs, including CEO Chae Myung-hoon. The company said it is cooperating with the investigation and would continue to do so should charges be forthcoming.

Charges may also be filed against 20 high-volume users who handled over KRW3b (US$2.8m) in margin trades via CoinOne. Approximately 19k CoinOne users made use of the margin trading product before it was shut down.