There is currently no margin trading (which may lead to debt) business. If he just uses his ID card to open a shareholder account and a third-party custody account, he can operate with his own funds. The risk is much smaller. It would be hard to say if he took the ID card to do other things (such as loans, futures speculation). Therefore, it is recommended that when providing a copy of your boyfriend's ID card, you should indicate the purpose of the copy (such as stock trading, third-party custody, etc.) and time on the photo of the ID card copy.