Investing.com -- Futu, a Hong Kong-based online broker, will stop allowing Chinese mainland investors to open or add to positions and transfer funds into accounts starting June 12, the company said Thursday. The move follows China's regulatory crackdown on cross-border securities trading.

Tiger and Longbridge, two other brokerages, released similar statements earlier this week.

Chinese regulators announced a crackdown on cross-border investment on May 22, targeting overseas firms and their local partners operating without approval.

The China Securities Regulatory Commission said on May 22 that it would penalize Futu, Tiger and Longbridge for conducting securities business services in China without regulatory approval or license. The regulator said it would confiscate all illegal gains from the three companies.

The service halts align with regulators' requirements for overseas institutions to wind down prohibited activities in a two-year grace period. During this time, customers can only sell existing holdings and withdraw funds. No new investments will be allowed.