Would negative SMA lead to a liquidation?

In order to avoid being subject to limited day trading, you will need to ensure your account Securities Net Liquidation Value has over USD 25,000 in value.

You can find an Overview of Pattern Day Trading ("PDT") Rules…

To avoid account liquidation, it is crucial to maintain positive balances and monitor key metrics in your Interactive Brokers (IBKR) account. Here is a comprehensive guide to help you prevent liquidation:

1. Understand Account-Specific Requirements:…

Market appreciation does add credit to a Reg T account's SMA. At the end of the regular trading day (normally 15:50 US/Eastern), there is a check for the amount of the Reg T Excess (Reg T Excess equals Reg T Equity less Reg T Margin). If the Reg T Excess of a margin account is greater than the previous end of day Reg T Excess then the account receives a credit and SMA and is set equal to the new amount of Reg T Excess. The change to SMA resulting from trades is effectively the change in Reg T Equity minus the change in Reg T Margin…

You can find the "SMA Rules" by going to the IBKR Margin Education page and scrolling down to “3. SMA and End of Day Calculations”. Once there, click on Real-Time SMA, End of Day SMA and SMA Rules…