USO gamma exposure: flip, call wall, put wall

Dealer gamma by strike for United States Oil Fund, 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 45 days.

data as of 2026-09-18 16:00:02 ET · not updating right now
Spot
153.8
from put-call parity
Zero gamma flip
153
0.5% below spot
Call wall
160
4.0% above spot
Put wall
150
2.5% below spot
Net gamma, volume
+$3M
per 1% move
Net gamma, OI
-$15M
per 1% move
Price sits above the flip at 153: 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.
Gamma by strike, two books on one axis
OPEN INTEREST · last close
STRIKE
VOLUME · today
164
163
162.5
162
161
160
call wall
159
158
157.5
157
156
155
154
spot
153
152.5
152
151
150
put wall
149.5
149
148.5
148
147.5
147
146.5
146
145
144.5
144
143.5
143
By expiry, volume book
expiryflipcallputnet
2026-09-23154.1160150-$390K
2026-09-25148.6156155+$6M
2026-09-30143160150+$534K
2026-10-02153.3165148+$159K
2026-10-09155.5163153-$238K
2026-10-16n/a160145-$3M
How far to trust this bookB

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

Prints a second, regular session1.31
Strikes where the two books agree on the sign92%
Contracts traded today, expiries shown164,619

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.
  • USO 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 USO, 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 USO 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.