Impact Cost and Slippage in Trading

1. What is Impact Cost? Impact Cost is the cost incurred due to the market movement caused by your own trade. It reflects how much your order moves the price of a stock due to liquidity constraints. In simple terms, it is the difference between the ideal price (based on bid-ask spread) and the actual execution price you get when placing a large order. 2. Real-Life Example Suppose the best buy price (bid) of a stock is ₹100, and the best sell price (ask) is ₹101. If you want to buy a large quantity, but there's not enough stock available at ₹101, your order might be partially filled at higher prices like ₹101.10, ₹101.30, etc. This extra amount paid above the ideal price (₹101) is your impact cost. 3. What is Slippage? Slippage refers to the difference between the expected price of a trade and the actual price at which the trade is executed. Slippage can occur during: • High volatility (price moves quickly) • Low liquidity (not enough buyers/sellers at expected levels) • Slow order execution (like during news events or network lag) 4. How It Affects Your Trading • In intraday or short-term trading, even small slippages or impact costs can ruin your risk-reward ratio. • For options or illiquid small-cap stocks, slippage can be significantly high. • Limit orders can help control slippage but may not always execute. 5. SEBI and NSE’s Use of Impact Cost NSE uses impact cost as a liquidity measure for stocks. A stock is considered liquid if it has an impact cost of less than 1% for ₹1 lakh order size. This is also used in deciding whether a stock can be included in derivatives (F&O) segment. 6. How to Minimize Impact Cost and Slippage • Use limit orders instead of market orders. • Avoid trading during opening or closing minutes when volatility is high. • Break large orders into smaller chunks using algo trading or manual staging. • Trade during high volume hours for better execution. • Use brokers that offer faster execution platforms.