The NIFTY expiry-day straddle with a 30% stop: busy, popular, and not clearly better than luck

The idea

Expiry day is when weekly options lose the last of their time value. A strategy popular with traders sells the at-the-money call and put of the expiring NIFTY weekly early in the morning, collects the premium, and buys both back in the afternoon, when much of that premium should have melted away. Because an at-the-money straddle loses money quickly if NIFTY trends, the popular version adds a stop on the combined premium: if the call and the put together cost 30% more than they were sold for, close both.

It is a short straddle without any protective options. The stop is an instruction to exit, not a limit on the loss.

The rules

• Days: every NIFTY weekly expiry day: Thursdays until August 2025, Tuesdays from September 2025, and the day before when the expiry fell on a holiday.
• Entry: at 9:20 am, sell one call and one put of the expiring weekly at the at-the-money strike (NIFTY at 9:20 am rounded to the nearest 50).
• Stop: close both legs the first minute the two options together close 30% above what they were sold for. Checked on every 1-minute close.
• Exit: otherwise, buy both back at 3:15 pm.
• Cost: built up from the published charge schedule at ten lots per order: ₹20 brokerage on each of the four orders, STT of 0.15% on the premium sold, exchange charges, SEBI fees, stamp duty and GST, plus a flat 0.25 point of slippage per option on each side. That comes to about 1.4 points per trade, round trip, of which 1.0 point is slippage. See Wrong costs, in either direction.

The backtest

Data: 1-minute NIFTY weekly option prices, 281 expiry days from April 2021 to August 2026 (5.4 years); every expiry day in the period was priced. Fills are taken at the 1-minute closes. All figures are per lot in NIFTY points (one lot = 65 units, today’s lot size, applied throughout).

(t measures whether the average trade is distinguishable from zero; around 2 or more is needed before we call a result more than luck.)

How a typical expiry day goes

• The stop fires more often than not. 153 of the 281 trades (54%) were stopped out. The average premium collected was about 111 points, so a stop costs roughly 33 points plus costs.
• The winners pay for it. The average win was +64 points, the average loss −36. A day on which NIFTY stays near the strike lets most of the premium decay: the best day, 3 February 2026, made +190 points on a 311-point straddle.
• The stop holds reasonably well. Because it is checked every minute and the trade never runs overnight, a stopped trade filled on average only about 4% of the premium beyond the 30% level. The worst single trade lost 89 points (30 March 2026, stopped at 9:36 am).

Losses include costs.

Where it falls short

The edge is thin. Costs of 1.4 points a trade took about a fifth of the gross profit, and what was left, about 5 points a trade, has a t of only 1.50. A strategy with no edge at all would produce a record like this about one time in seven.

Two good years. Year by year, per lot:

*From April 2021; 2026 up to 11 August.

2022 and 2023 together made 6 points. Almost all the profit came from 2024 and 2025, when expiry-day premiums were larger: the average straddle sold for 84 points in 2023 and 135 in 2024.

The Tuesday era so far. NIFTY’s weekly expiry moved from Thursday to Tuesday in September 2025. The 231 Thursday-era trades made +1,236 points (t 1.44); the 50 Tuesday-era trades made +201 (t 0.47). Premiums were higher in the Tuesday era (128 points against 108), but a year of trades is too short to say whether anything has changed.

What it takes in capital. A short straddle needs about ₹2.25 lakh of margin per lot. Losses on sold options arrive during the day, so we size the buffer on the worst intraday drawdown: 574 points × 65 ≈ ₹0.37 lakh, from January to June 2022. That makes the capital about ₹2.6 lakh, on which the average profit of about ₹17,400 a year is a return of about 6.6% a year, just short of a deposit. That drawdown took about 14% of the capital.

Robustness tests

The pessimistic row is a worst case, not a forecast: it assumes both options hit their highs of the minute at the same time and the stop fills there. It shows how much of this strategy depends on getting filled close to the price on the screen.

Changing one setting at a time:

• Every nearby setting made money, but the plateau is uneven. Entering ten minutes later, at 9:30 am, almost doubled the profit and cleared our bar; the stop and exit changes stayed near the original. A result that swings this much with a ten-minute shift is a reason for caution, not a reason to choose 9:30 am after the fact: that would be fitting the rule to the past.
• Only 16 of 22 quarters were profitable, well short of the 85% we expect from option selling. The worst quarter (July to September 2023, −367 points) was about 2½ times a typical good one.
• Not carried by a few trades. Without its five best trades it still made +555 points, and no quarter made more than a fifth of the profit.

A popular filter. A variant that also circulates only trades when the straddle’s premium is above its average of the previous 20 expiries. From August 2021 it traded 109 of 261 expiry days and made +1,681 points (t 2.19), against +1,330 for the unfiltered rule over the same days. That looks better, but premiums rose steadily over the period, so “above the recent average” mostly picked the later, better years. One test of one filter is not enough to rely on.

Risks

• No ceiling on a bad day. Nothing is bought to cap the loss. The stop is a market exit; a sudden jump in NIFTY, or a frozen or illiquid moment near the strike, can fill well beyond 30%.
• Fills. The profit per trade is small enough that a point of slippage matters. Assuming worse fills than the 1-minute close turned the result negative.
• Margin. Expiry-day margins and rules have been tightened repeatedly; the capital needed today may differ from what we assumed.
• Rule changes. The weekly expiry day, the number of weekly expiries and the lot size have all changed in recent years and may change again.
• A short Tuesday record. Only a year of trades since the expiry moved to Tuesday.

Pros & cons

Pros

• Simple and mechanical: one entry, one stop, one exit, every week.
• Intraday only: no overnight or weekend gaps.
• The stop, checked every minute, kept losses close to the planned size.
• Every nearby setting we tried was profitable.

Cons

• After costs, the profit is not distinguishable from luck (t 1.50).
• Loses on about six trades in ten; long losing runs are normal.
• 2022 and 2023 made almost nothing; most of the profit came from 2024 and 2025.
• About 6.6% a year on capital, below a deposit.
• Very sensitive to fills and to the exact entry time.

Our verdict

It passed three of our eight checks: it held up in both halves of the test, the profit was not carried by a few trades, and there were plenty of them. But after realistic costs the edge was too small to tell apart from luck, its return on capital fell just short of a deposit, it was profitable in only 16 of 22 quarters, and doubling the costs or assuming worse fills took much of the profit away.

The idea is not empty: before costs it made money, and a slightly later entry did better. But as specified, a 9:20 am straddle with a 30% stop is a busy way to earn little, with the uncapped risk of a naked short option every week.