Does a stop-loss help the short straddle? Not the way you'd think

"Always use a stop-loss" is the first rule anyone learns. But on a short option straddle, a stop does something specific: it turns a temporary paper loss into a realised one. So we tested it honestly — the same NIFTY 9:45 ATM straddle, three exit rules — no stop (hold to 3:20), a fixed 40-point-per-leg stop, and a 40-point trailing stop. Stops are assumed to fill at the price that breached them, not at the level itself.

The stops cost more than they saved

No stop earned the most (+1,856) and had the best Sharpe. Both stops did trim the drawdown — from −686 to about −550 — but each gave up far more in return than it saved in risk. The trailing stop was worst of all, netting less than half of no-stop.

Takeaway

This is not "never use a stop" — an unhedged straddle with no risk control can still hand you a catastrophic day, and a single 40-point stop level on one window is a narrow test. But it is a warning: on a mean-reverting, premium-selling strategy, a tight stop is not free insurance. It has a real, measurable cost, and here that cost outweighed the protection. Size the position for the bad day instead of stopping into it.