XLK gamma exposure: flip, call wall, put wall

Dealer gamma by strike for Technology Select Sector SPDR, 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 16:13:03 ET · not updating right now · replay XLK in the terminal
Spot
196.4
from put-call parity
Zero gamma flip
200.5
2.1% above spot
Call wall
198
0.8% above spot
Put wall
193
1.7% below spot
Net gamma, volume
-$3M
per 1% move
Net gamma, OI
+$15M
per 1% move
Price sits below the flip at 200.5: on this book dealer hedging adds to a move rather than leaning against it. The two books disagree: price is above one flip and below the other, and that split is the reading.
The session, 2026-10-07 priceflipcall wallput wall
205195206.1201.4 net gamma, volume book09:3010:3011:3012:3013:3014:3015:30
day10-1210-0910-0810-0710-0610-0510-0210-0109-3009-2909-2809-25 83 points · volume book · levels drawn as they stood
Strikes through the day levelchange since the open absorbs a movefeeds itprice
215212.5210207.5205202.5200199198197.5197196195194193192.5192191190189188187.518709:3010:3011:3012:3013:3014:3015:30
Gamma by strike, two books on one axis
OPEN INTEREST · last close
STRIKE
VOLUME · today
210
207.5
205
202.5
200
199
198
call wall
197.5
197
196
spot
195
194
193
put wall
192.5
192
191
190
189
188
187.5
187
186
185
184
183
182.5
182
181
By expiry, volume book
expiryflipcallputnet
2026-10-16196.2197.5193+$112K
2026-10-23197.6205195-$77K
2026-10-30205205197.5-$288K
2026-11-06n/a197.5199-$446K
2026-11-13n/a202.5199-$52K
2026-11-20n/a210190-$1M
How far to trust this bookB

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

Prints a second, regular session0.17
Strikes where the two books agree on the sign86%
Contracts traded today, expiries shown12,910

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.
  • XLK 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 XLK, 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 XLK 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.