Fill Price

The fill price is the actual price at which a buy or sell order for a security is executed — the price at which the trade is confirmed and the transaction is recorded in the exchange's matching engine. For market orders, the fill price is the best available price in the order book at the moment the order reaches the exchange — which may differ slightly from the last traded price visible to the investor at the time of order placement, due to the time lag between order entry and execution. For limit orders, the fill price is either the specified limit price or better — a buy limit order fills at the limit price or lower, while a sell limit order fills at the limit price or higher. In fast-moving markets — particularly during Nifty 50 or Bank Nifty options expiry sessions, post-result gap moves, or circuit-hit situations — significant differences between the expected price and the actual fill price (slippage) can occur, particularly for large orders or illiquid securities. Understanding fill prices and potential slippage is critical for traders accurately calculating their actual returns, brokerage costs, and the viability of short-term trading strategies in Indian equity and derivatives markets.