What figures should I review to ensure I avoid a liquidation?

Any open position can be closed by the IBKR Liquidation system when an account is in a margin deficit. To avoid a Liquidation a Reg T Margin account must have positive Excess Liquidity at all times and Positive SMA starting at 15:50 EST which is the start of the Reg T check period. A Margin or Portfolio Margin account must have positive Excess Liquidity at all times. A Cash account must have a positive cash balance at all times.

You can monitor your account's margin compliance in real time in the Account Window in TWS, on the Portfolio - Positions page in Client Portal or on the Account-Funds screen in IBKR Mobile.

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How can I avoid account liquidation?
How do I choose between a Cash, Reg T Margin or Portfolio Margin account?
Does SMA increase when the value of my Reg T account increases?
How much stock do I need to sell in order to meet IBKR's liquidity standards?