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 15:57:45 ET · replay NDX in the terminal
Spot
30663
from put-call parity
Zero gamma flip
30661
0.0% below spot
Call wall
30670
0.0% above spot
Put wall
30650
0.0% below spot
Net gamma, volume
+$4.02B
per 1% move
Net gamma, OI
-$1.45B
per 1% move
Price sits above the flip at 30661: on this book dealer hedging leans against a move rather than adding to it. The two books disagree: price is above one flip and below the other, and that split is the reading.
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
30790
30780
30775
30770
30760
30750
30740
30730
30725
30720
30710
30700
30690
30680
30675
30670
call wall
30660
spot
30650
put wall
30640
30630
30625
30620
30610
30600
30590
30580
30575
30570
30560
30550
30540
By expiry, volume book
expiryflipcallputnet
2026-10-12 · 0DTE306613067030650+$4.09B
2026-10-13306453080030500+$164M
2026-10-14308603100030590-$191M
2026-10-15307563073030675-$25M
2026-10-16306063100029900+$49M
2026-10-19308923150030250-$71M
How far to trust this bookB

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

Prints a second, regular session1.22
Strikes where the two books agree on the sign75%
Contracts traded today, expiries shown54,291

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 above its flip?

Net dealer gamma on this book is positive, so hedging flows tend to lean against 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.