TSM gamma exposure: flip, call wall, put wall

Dealer gamma by strike for Taiwan Semiconductor, 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 16:00:03 ET · not updating right now
Spot
434.3
from put-call parity
Zero gamma flip
426.7
1.7% below spot
Call wall
450
3.6% above spot
Put wall
425
2.1% below spot
Net gamma, volume
+$20M
per 1% move
Net gamma, OI
+$52M
per 1% move
Price sits above the flip at 426.7: on this book dealer hedging leans against a move rather than adding to it.
Gamma by strike, two books on one axis
OPEN INTEREST · last close
STRIKE
VOLUME · today
472.5
470
467.5
465
462.5
460
457.5
455
452.5
450
call wall
447.5
445
442.5
440
437.5
435
spot
432.5
430
427.5
425
put wall
422.5
420
417.5
415
412.5
410
407.5
405
402.5
400
397.5
By expiry, volume book
expiryflipcallputnet
2026-09-25424.9435425+$19M
2026-10-02434.5452.5425-$44K
2026-10-09433450380+$190K
2026-10-16427.3450430+$1M
2026-10-23465.4430435-$460K
2026-10-30480.2445420-$411K
How far to trust this bookD

a single stock with a thin tape; read the shape, not the sign.

Prints a second, regular session0.56
Strikes where the two books agree on the sign92%
Contracts traded today, expiries shown56,641

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.
  • TSM 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 TSM, 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 TSM 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.