Expiry Day Pinning — Does NIFTY Really Settle at Max Pain?

Every expiry morning someone posts the max pain level and calls it the target. The claim is testable, so we tested it against our own logged option chain snapshots. The magnet is real in a much weaker sense than the folklore suggests — and the evidence usually offered for it is measured in a way that cannot fail.

The Claim, and Why It Is Seductive

Max pain is the strike at which option buyers collectively lose the most, and therefore where writers pay out the least. Our max pain guide covers the calculation in full. The trading folklore built on top of it goes further: because writers are large, well-capitalised and motivated, the index is said to gravitate toward that strike as expiry approaches.

It is an appealing story because it has a mechanism. Writers do hedge, hedging flow does concentrate around heavy open interest, and a delta-hedged book genuinely does buy weakness and sell strength near the strikes it is short. None of that is imaginary.

The question is not whether that force exists. It is whether the force is large enough to be worth trading — and whether the evidence normally cited for it actually measures anything.

The Measurement That Cannot Fail

The usual demonstration is a screenshot: here is where max pain was, here is where the index closed, look how close. We can run that test properly. Across 37 expiry sessions where we captured a snapshot on the expiry date itself, the gap between the last captured spot and the max pain at that same moment had a median of 0.06% — and every single session came in under 0.25%.

That looks like overwhelming confirmation. It is close to meaningless, for two reasons.

Max pain is recomputed from live open interest

Max pain is not a fixed level set in the morning. It is recalculated from whatever open interest currently exists. As expiry day progresses, positions at distant strikes settle or are unwound, so the strikes still carrying meaningful open interest are increasingly the ones near spot. The calculation therefore drifts toward the index on its own.

Comparing end-of-day max pain with end-of-day spot compares a number derived largely from current prices against current prices. It confirms the arithmetic, not the theory.

The answer can only be a strike

Max pain is evaluated per strike, so the output is always one of the listed strikes. NIFTY strikes are 50 points apart; SENSEX strikes 100. By construction the nearest strike to spot is never more than half an interval away — 25 points on NIFTY.

A median gap of 0.06% on a 24,000 NIFTY is about 15 points. That is smaller than half a strike interval, which means the statistic is largely measuring the coarseness of the strike grid. Any level that snaps to the nearest strike would score similarly well.

The Honest Test

So we ran it the other way. Take the max pain from our first snapshot of the expiry session — the morning reading, before the day has resolved anything — and compare it against where the index actually ended up in our last snapshot of that session. That is a real forecast: fixed in advance, judged afterwards.

Nineteen sessions qualified, meaning we had both a morning capture and a later one at least 90 minutes apart: nine NIFTY, eight SENSEX and two BankNifty expiries between May and August 2026.

The level that writers are supposedly dragging the index toward was a worse predictor than assuming the index would stay exactly where it opened. It beat that baseline in 8 of 19 sessions — slightly worse than a coin flip.

The direction test is no kinder. In each session we asked whether the index moved toward the morning max pain or away from it. It moved toward in 8 sessions and away in 11.

Why the Illusion Is So Convincing

The median move between our first and last capture of an expiry session was about 0.20%. On a 24,000 NIFTY that is roughly 48 points — around one strike.

That is the whole trick. When the index typically travels about one strike over the session, every level within a strike or two of spot will look prescient most of the time. Max pain is near spot by construction. So is the previous close. So is any round number nearby. All of them will produce impressive-looking screenshots, and none of them are forecasting anything.

This is also why the folklore is so resistant to correction. The failures are memorable but rare, and each one gets explained away as a news day. The successes are frequent, unremarkable, and quietly attributed to the magnet.

What Max Pain Is Still Good For

None of this makes the number worthless. It makes it a different kind of number than advertised — a description of positioning rather than a forecast of price.

• It marks where writer exposure is concentrated. The strikes around max pain are where hedging flow is densest, which makes them the levels most likely to produce a reaction — not the levels the index must reach.
• It frames a range, not a target. Read alongside the heavy call and put open interest walls, it helps define where the session is likely to be contained. A range is a defensible read; a point is not.
• A large gap is the informative case. When max pain sits far from spot, that gap says positioning and price disagree. That is worth noticing precisely because it is unusual — and it still does not tell you which one moves.
• Its movement matters more than its level. Max pain shifting up through the session means fresh put writing below; shifting down means call writing above. The direction of the change carries more information than the number.

How to Use the Expiry Session Instead

• Start from the range, not the point. Take the nearest heavy call OI above and put OI below. That band is the day's likely container, and it is falsifiable — if the index leaves it, your read was wrong and you know immediately.
• Expect a small day and size for a large one. A typical expiry session moves about a fifth of a percent. The occasional session that moves five times that is what determines whether the strategy survives the year.
• Watch where OI is being added, not where it already sits. Existing open interest is history. Fresh build-up during the session is the live signal — our OI build-up guide covers the four signatures and when each one lies.
• Respect the new closing mechanics. With the Closing Auction Session in force, cash settles via auction between 3:15 and 3:30 PM while derivatives run to 3:40 PM. Rules written around the old continuous 3:30 close need rechecking.
• Decide the exit before the entry. On expiry day the position that was comfortable at 2 PM can be unrecognisable at 3 PM. Nothing about max pain protects you from that.

What This Study Does Not Prove

Being honest about the evidence cuts both ways, so the limits are worth stating plainly.

• Nineteen sessions is a small sample. It covers roughly four months of 2026 across three indices. It is enough to show the effect is not the reliable magnet it is sold as; it is not enough to rule out a weak effect.
• Our snapshots are not the official close. We capture the chain periodically through the session, so the "end of session" here is our last capture, which in some sessions lands well before 3:30 PM. The comparison is consistent across predictors, but it is not settlement data.
• One market regime. May to August 2026 was not an especially volatile stretch. Pinning behaviour could genuinely differ when volatility is high — though that is also when the strategies built on it fail hardest.
• This is not a backtest of a strategy. It tests one claim: whether max pain forecasts where the session ends. It says nothing about intraday paths, or whether the level acts as short-term support and resistance along the way.

Where to Go Next

• Max Pain — how the level is calculated, step by step
• Gamma — why expiry-day moves accelerate the way they do
• Theta — the decay that makes the final session different from every other
• OI Build-up Patterns — reading fresh positioning as it forms
• Put-Call Ratio — the other number that gets over-read on expiry day