NIFTY expiry 21 July 2026: what the 24,200 options did in the last 30 minutes
On Tuesday 21 July 2026 the NIFTY strike nearest the index at 15:00 was 24,200. The index went from 24,195 at 15:00 to 24,193 at 15:30, down 2 points across the settle walk.
The at-the-money legs, 15:00 to 15:30
| Leg | 15:00 | High | Low | 15:30 | End vs 15:00 | Open interest |
|---|---|---|---|---|---|---|
| 24,200 CE | ₹12.0 | ₹12.0 15:00 | ₹0.1 15:22 | ₹0.1 | worthless | 66.9M → 45.5M |
| 24,200 PE | ₹15.4 | ₹18.8 15:01 | ₹10.2 15:03 | ₹12.2 | 0.8× | 34.3M → 17.0M |
Premium of the strike nearest the index at 15:00, sampled every ten seconds from the NSE option chain. Index values are the chain's own quote. Dotted verticals mark a pin-book flip on Gamma Terrain.
What happened
The 24,200 call was ₹12.0 at 15:00. It never traded meaningfully above its 15:00 price. Its low was ₹0.1 at 15:22, less than half of where it started the half hour. It ended at ₹0.1, worthless. Open interest at the strike went from 66.9 million to 45.5 million, so positions were closed through the window.
The 24,200 put was ₹15.4 at 15:00. Its high was ₹18.8 at 15:01. It ended at ₹12.2, 0.8× the 15:00 price. Open interest at the strike went from 34.3 million to 17.0 million, so positions were closed through the window.
Gamma Terrain's pin-book read flipped: at 15:21 the resting depth read the put strikes below the pin thinning (puts 37 %, calls 85 % of their baseline); at 15:30 the resting depth read the call strikes above the pin thinning (puts 93 %, calls 18 % of their baseline). A flip names the side whose book is emptying. Across 45 sessions it has not been a direction tell, it is a vacuum tell.
Chain quotes were missing 15:00–15:01, 15:01–15:02, 15:02–15:03, 15:03–15:04, 15:04–15:05, 15:05–15:06, 15:06–15:07, 15:07–15:08, 15:08–15:09, 15:09–15:10, 15:10–15:11, 15:11–15:12, 15:12–15:13, 15:13–15:14, 15:14–15:15, 15:15–15:16, 15:16–15:17, 15:17–15:18, 15:18–15:19, 15:19–15:20, 15:20–15:21, 15:21–15:22, 15:22–15:23, 15:23–15:24, 15:24–15:25, 15:25–15:26, 15:26–15:27, 15:27–15:28, 15:28–15:29, 15:29–15:30: the exchange rate-limited the poll in the endgame, so the chart shows a hole there rather than a line. Highs and lows inside a hole are not known.
For context, across 21 NIFTY and SENSEX expiries measured to 2026-09-08, 15 of 42 at-the-money legs doubled at some point in this window, 26 lost half, and 13 ended at or above their 15:00 price. This page states what the tape did. It is not a recommendation to buy or sell anything.
Gamma Terrain shows the pin, the walls, the book read and every large print, tick by tick, on NIFTY and SENSEX.
The recap is the after-photo. The terrain is the window while it happens.
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