Margin trading: The maximum funds you can borrow to buy shares depend on the initial margin requirement and your account assets. The margin requirement may vary by stock.
To learn the maximum funds available on margin, please refer to the Max Qty to Buy field on the Trade page.
Short selling: The maximum number of shares you can borrow depends on the initial margin requirement and your account assets. When you do not have enough cash, the system will automatically calculate your account assets that can serve as collateral, including but not limited to cash, holdings, funds on hold.
To learn the maximum number of shares you can sell short, please refer to the Max Qty to Sell Short field on the Trade page.