KuCoin is a subsidiary of a Seychelles-registered company called MEK Global Limited (MGL), the bank said in a statement.

MGL "is acting in violation of the law on preventing money laundering and financing terrorism and offering illegal services," De Nederlandsche Bank said.

KuCoin did not immediately respond to an emailed request for comment.

Customers of the exchange are not breaking the law, the DNB said, "but they may have a heightened risk of becoming involved in money laundering and terrorism financing."

In August 2021, the DNB issued a similar warning that Binance Holdings Ltd. was operating in the Netherlands without a license. That led to the company setting up an entity in the country and paying a $3.3 million fine in April 2022.

(Reporting by Toby Sterling;Editing by Elaine Hardcastle)