NDX gamma exposure: flip, call wall, put wall

Dealer gamma by strike for Nasdaq-100 index, from the option chain itself: two books, the level where net gamma changes sign, and the two strikes that carry the most. Expiries out to 120 days.

data as of 2026-10-12 14:57:45 ET · replay NDX in the terminal
Spot
30629
from put-call parity
Zero gamma flip
30672
0.1% above spot
Call wall
30700
0.2% above spot
Put wall
30600
0.1% below spot
Net gamma, volume
-$41.35B
per 1% move
Net gamma, OI
-$1.25B
per 1% move
Price sits below the flip at 30672: on this book dealer hedging adds to a move rather than leaning against it.
The session, 2026-10-09 priceflipcall wallput wall
31000307003082830884 net gamma, volume book09:3010:3011:3012:3013:3014:3015:30
day10-1210-0910-0810-0710-0610-0510-0210-0109-3009-2909-2809-25 84 points · volume book · levels drawn as they stood
Strikes through the day levelchange since the open absorbs a movefeeds itprice
309753097030960309503094030930309253092030910309003089030880308753087030860308503084030830308253082030810308003079009:3010:3011:3012:3013:3014:3015:30
Gamma by strike, two books on one axis
OPEN INTEREST · last close
STRIKE
VOLUME · today
30750
30740
30730
30725
30720
30710
30700
call wall
30690
30680
30675
30670
30660
30650
30640
30630
spot
30625
30620
30610
30600
put wall
30590
30580
30575
30570
30560
30550
30540
30530
30525
30520
30510
30500
By expiry, volume book
expiryflipcallputnet
2026-10-12 · 0DTE306723070030600-$41.06B
2026-10-13306323080030650-$18M
2026-10-14308493072530590-$164M
2026-10-15307203073030675-$20M
2026-10-16306433100030800-$11M
2026-10-19308963060030700-$74M
How far to trust this bookB

an index or an ETF; the convention holds, the tape is thinner.

Prints a second, regular session1.66
Strikes where the two books agree on the sign81%
Contracts traded today, expiries shown76,481

What this page assumes

  • Calls count as dealer-long gamma and puts as dealer-short. That is a convention, not a measurement: open interest does not say who holds a contract.
  • The volume book signs today's traded contracts. The open-interest book uses positions as of the last close and does not move inside the day.
  • Spot is derived from the option quotes by put-call parity, so it can sit a few cents from the last trade in the underlying.
  • Two roots of the index, the daily and the monthly, are added together on the dates they share.
  • Every figure is dollars of dealer delta per 1% move in NDX, the unit that compares across symbols.
  • There is no tape-signed book on this page. That book exists only where a live engine runs.

Questions

What does it mean that NDX is below its flip?

Net dealer gamma on this book is negative, so hedging flows tend to add to a move. It says nothing about direction.

Why are there two books?

Open interest is positioning as it stood at the last close. Volume is what traded today. When they disagree, that split is the reading.

Is this a trading signal?

No. We tested wall touches and flip crosses on SPX across more than a thousand sessions and found no edge that survives costs. These are measurements of where hedging concentrates.

How is this different from the SPX terminal?

SPX runs on a live engine: every second, with a third book signed print by print from the trade tape. This page is rebuilt from chain snapshots and carries the two conventional books only.