Why is my trading-account balance negative?

A negative balance most commonly happens when charges, like brokerage, taxes, or an auto square-off fee, get deducted after you’ve already used most or all of your available funds for a trade, pushing the account below zero once the exact charge amount is applied. It can also happen with F&O positions if a mark-to-market loss on an open position exceeds the margin you had available, particularly overnight positions where the market moves against you before you can add funds or exit. A failed or reversed transaction, like a bounced fund transfer that had already been treated as usable, can also leave a temporary negative balance once the reversal processes. You check the ledger statement for the specific transaction that pushed the balance negative, since the fix (adding funds versus disputing an incorrect charge) depends entirely on the cause, and you add funds promptly if it’s a genuine shortfall, since a negative balance can restrict further trading until resolved.