One Venue Carries the Book, and That Changes the Read

Deribit carries the overwhelming majority of crypto options open interest. For anyone computing dealer positioning that is a remarkable convenience: the chain is public, the API is open, and it is close to the whole market rather than a sample of it.

Equity market structure has no equivalent. There, open interest is distributed across many venues and the aggregate has to be assembled from a consolidated feed.

Why concentration helps the calculation

A gamma map multiplies open interest by gamma at each strike. If your open interest is a fraction of the real total, every figure is scaled wrong — and worse, wrong by an unknown factor that varies by strike.

When one venue holds nearly all of it, that error mostly disappears. The walls, the flip and the net figure computed from that one book are close to the market’s real structure rather than a partial view of it, which is what makes Bitcoin gamma exposure genuinely computable.

What concentration costs

A single point of failure in the read. An outage, an API change or a policy change at one venue and the map is not degraded — it is absent. There is no second source to fall back to that carries comparable open interest.

And it makes the dealer read a read on that venue’s participants. Its user base is not the whole market, so the positioning inferred is the positioning of the people who trade there. That is most of the options market, but it is not everyone, and the assumption is worth stating rather than forgetting.

The second book that is not on it

For BTC and ETH there is now a large options market that Deribit does not carry at all: the US-listed ETF book. It has real open interest, real hedging, and different participants — and it is a separate map, not an addition to this one, for the reasons in IBIT is not Bitcoin.

So “the crypto options market” for BTC now means two concentrated books, on two clocks, with two sets of participants. Reading either as the whole is the error.

Below the majors

The concentration argument weakens fast as you go down the list. On the smaller listed coins the book exists but is thin, and thin books misbehave in specific ways — see reading a thin options book. Everything else has no book at all, and there the structure to read is leverage, not gamma.