IBIT is the largest regulated bitcoin options book and it behaves nothing like CME crypto. Live gamma, the overwriting dynamic that keeps dealers long gamma, and where the walls actually sit.
When bitcoin ETF options were approved, the assumption was that they would be a smaller mirror of the CME book. They are not. IBIT's options book has a different shape because it has a different owner: people who hold the ETF as a long-term position and sell calls against it. That single behavioural fact drives most of what the gamma profile looks like.
Read before the US open on 17 August 2026, on settled open interest:
Measure
Value
Spot
35.93
Gamma flip
35.90
Net GEX
+$3.98M
Regime
Positive gamma - dealers dampen
Distance to flip
+0.06%
Spot is sitting essentially on the flip. That is the least stable configuration a book can be in: the sign of dealer hedging inverts on a six-basis-point move. Above 35.90, dealers sell into strength and buy into weakness. Below it, they do the opposite and every move gets a push.
Where The Walls Are
The strike map is lopsided in a very specific way:
Strike
Net GEX
Call OI
Put OI
Reading
38.5
+$1.00M
12,406
648
Upper call shelf
37.5
+$5.71M
31,279
2,457
Largest call OI in the book
36.5
+$9.74M
24,582
12,003
Call wall
36.0
+$0.27M
3,619
1,847
Thin
35.5
−$6.48M
1,416
24,112
Put wall
34.5
−$5.38M
191
27,148
Largest put OI in the book
33.0
−$0.43M
101
4,646
Lower put shelf
Two things stand out. First, the call wall at 36.5 carries $9.74M of positive gamma, the largest single concentration in the book, and it sits about 1.6% above spot. Second, the put side is not a hedging wall in the usual sense - 27,148 puts at 34.5 against just 191 calls is not a two-way strike, it is a floor of protective puts bought outright.
Note the asymmetry in open interest. The 37.5 calls (31,279 contracts) and 34.5 puts (27,148) are the two largest lines in the book, and they sit on opposite sides of spot roughly equidistant. That is the fingerprint of a collar: long holders selling upside and buying downside against an existing ETF position. It is the single most important structural fact about this book.
Why Dealers Stay Long Gamma Here
The mechanism is simple and it repeats. An investor holds IBIT as a core position. They sell a covered call to generate yield. The dealer on the other side is long that call, which means long gamma. Repeat across thousands of accounts and the aggregate dealer book tilts persistently long gamma.
A dealer who is long gamma hedges by selling as price rises and buying as it falls. That is a mean-reverting force. It is why IBIT often grinds where the underlying asset lurches, and why realised volatility on the ETF can print below what the same exposure delivers on CME or offshore.
The dynamic has a limit. Once spot pushes decisively through the call wall - here 36.5 - those short calls go in the money, the overwriters get assigned or roll, and the gamma that was dampening the move disappears. That is the point at which IBIT stops behaving like a mean-reverting instrument and starts tracking bitcoin move-for-move.
How This Differs From CME
At the same instant, CME BTC=F showed −$0.85M net gamma with spot 0.1% below its flip - dealers short gamma, amplifying. IBIT showed +$3.98M with spot just above its flip - dealers long gamma, dampening.
That is the same asset, at the same moment, with opposite dealer behaviour. It is not an arbitrage: the CME book is hedged in CME futures by funds and basis desks, the IBIT book is hedged in ETF shares against overwriting flow. The flows do not net against each other because they never meet.
The practical rule: if you hold IBIT, IBIT gamma is your tape. CME gamma tells you what a different set of people are doing in a different instrument.
Reading It Day To Day
Check the flip first. Distance to flip matters more than the headline GEX number. At 0.06% you are in a regime that can invert intraday.
Treat the call wall as a friction level, not a ceiling. 36.5 is where dampening is strongest, not where price is forbidden to go.
Watch for the wall breaking. Sustained trade above the call wall removes the dampening and changes the character of the tape.
Do not read the put wall as support. When put OI dwarfs call OI at a strike, it is protection buying, not two-way dealer positioning. It does not create the same hedging bid.
Re-read after monthly expiry. Overwriting flow is monthly. The strike map resets and the walls move.
Pulling It
GET /v1/exposure/gex/IBIT # full-chain gamma - Growth plan
GET /v1/exposure/gex/IBIT?expiration=2026-09-18 # single expiry - all plans
GET /v1/exposure/summary/IBIT # net GEX/DEX/VEX/CHEX - Growth plan
GET /v1/levels/IBIT # key levels incl. max pain
GET /v1/stock/IBIT/summary # incl. IV term structure
IBIT is an ordinary equity symbol, so unlike BTC=F it needs no %3D encoding and carries no futures entitlement. Tiering still applies by endpoint rather than by symbol: full-chain GEX and the exposure summary require the Growth plan, while filtering to a single expiry with ?expiration= works on lower plans. The same shape works for ETHA, MSTR and COIN.
IBIT is not a smaller copy of the CME bitcoin book. It is structurally long dealer gamma because it is structurally overwritten, which makes it a dampened, mean-reverting expression of bitcoin for as long as spot stays below the call wall. Read the distance to flip before the headline number, treat the 36.5 call wall as the level where that dampening is strongest, and recognise that the heavy put open interest below spot is protection rather than support. When spot clears the call wall, the instrument changes character - that transition is the thing worth watching.
