IWM gamma exposure: flip, call wall, put wall

Dealer gamma by strike for iShares Russell 2000 ETF, 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 14:58:26 ET · replay IWM in the terminal
Spot
278
from put-call parity
Zero gamma flip
278.9
0.3% above spot
Call wall
279
0.4% above spot
Put wall
278
0.0% above spot
Net gamma, volume
-$3.72B
per 1% move
Net gamma, OI
-$4.60B
per 1% move
Price sits below the flip at 278.9: on this book dealer hedging adds to a move rather than leaning against it.
The session, 2026-10-09 priceflipcall wallput wall
280270278.8278.9 net gamma, volume book09:3010:3011:3012:3013:3014:3015:30
day10-1210-0910-0810-0710-0610-0510-0210-0109-3009-2909-2809-25 82 points · volume book · levels drawn as they stood
Strikes through the day levelchange since the open absorbs a movefeeds itprice
288287.5287286285284283282.5282281280279278277.5277276275274273272.527227127009:3010:3011:3012:3013:3014:3015:30
Gamma by strike, two books on one axis
OPEN INTEREST · last close
STRIKE
VOLUME · today
290
289
288
287.5
287
286
285
284
283
282.5
282
281
280
279
call wall
278
put wall · spot
277.5
277
276
275
274
273
272.5
272
271
270
269
268
267.5
267
266
265
By expiry, volume book
expiryflipcallputnet
2026-10-12 · 0DTEn/an/a278-$3.89B
2026-10-13276.6279277+$116M
2026-10-14274.8285275+$103M
2026-10-15274.5279277+$10M
2026-10-16277.5283275+$11M
2026-10-19282282279-$6M
How far to trust this bookB

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

Prints a second, regular session2.71
Strikes where the two books agree on the sign88%
Contracts traded today, expiries shown591,935

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.
  • IWM options are American style and the underlying may pay a dividend. Each expiry is priced off its own forward from put-call parity, and gamma is Black-Scholes on that forward. Deep in-the-money contracts near a dividend are the weak spot.
  • Every figure is dollars of dealer delta per 1% move in IWM, 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 IWM 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.