Trailing Stop Methods
Trailing stop methods are dynamic stop-loss techniques that move the exit level in the direction of a profitable trade to lock in gains progressively, while still allowing the trade room to continue developing in the favoured direction.
A trailing stop differs from a fixed stop-loss in that it moves in only one direction — in favour of the trade — as price advances. Once moved, it does not revert. This mechanism allowed practitioners to stay in profitable trends for extended periods while systematically protecting an increasing portion of accumulated gains.
The percentage trailing stop was the simplest implementation. A trader long on a stock at Rs 1,000 might set a 5% trailing stop. Initially the stop was at Rs 950. If the stock rose to Rs 1,200, the stop moved to Rs 1,140. If the stock then fell to Rs 1,100, the stop remained at Rs 1,140 and the trade would be exited at that level, locking in Rs 140 per share of gain. The limitation of percentage trailing was that it did not adapt to market volatility — a 5% trail was very tight for a high-ATR stock and very loose for a low-ATR stock.
ATR-based trailing stops addressed this limitation. The stop was set at a multiple of the ATR below the high of the trade. If the ATR was Rs 40 and the multiplier was 3, the stop trailed at the highest high minus Rs 120. As price made new highs, the stop automatically ratcheted up. When the price pulled back Rs 120 from its high, the stop was triggered. This system was popularised by systems traders including John Chandler, and the Chandelier Exit (developed by Charles Le Beau) used this ATR trailing approach.
Moving average trailing stops used a moving average as the stop level. A trader long on a stock might stay in as long as price remained above the 20-day EMA, trailing the stop just below the EMA. This approach was used in Indian momentum strategies — a stock breaking above a 200-day moving average and then being held until it closed below the 50-day EMA was a simple implementation. The limitation was that moving averages lagged price significantly and could give back a large portion of profits before triggering.
In Indian market conditions, trailing stops needed to account for overnight gaps. A stock that closed above the trailing stop level but opened the next morning below it due to adverse news would be exited at the gap-down open, not the intended stop price. F&O stops could also gap through, and this slippage risk was a real execution consideration that percentage trailing calculations often ignored.