What is a Margin Account?

A margin account is an account that can be used for margin trading. When you open a margin account for US stocks, the securities and assets in your account (that is, the net assets of the account) will be regarded as collateral. When the "net worth" of the account is lower than the initial margin required for margin trading, you need to deposit more money, or you can close part of your position.

Note: after opening a margin account, you can still use your own cash for trading. As long as the market value of the order does not exceed your cash buying power, your account will not be charged any interest.