Vanna is the sensitivity of an option’s delta to a change in implied volatility. A dealer hedged on delta must re-hedge when volatility moves, even if spot has not — the mechanic in charm and vanna.
It only produces a systematic flow where volatility and price are systematically related. In equity indices they are, strongly and negatively: falling prices lift implied volatility, which is what makes vanna flow a recognisable force there.
The crypto relationship is weaker and less signed
Crypto volatility rises on large moves in either direction. A violent rally lifts implied volatility much as a decline does, because the market is not primarily hedging downside — the call-heavy book again.
So the tidy equity relationship — down means vol up — does not hold. Vanna flow still exists and its sign is less predictable, which makes it a weaker input rather than an inverted one.
Where it shows up anyway
Around events. When implied volatility collapses after a scheduled catalyst resolves, that repricing forces vanna-driven re-hedging across the whole book at once — the collapse described in scheduled catalysts.
That is the one moment where crypto vanna flow is concentrated enough to be worth naming, and it is predictable in timing if not in direction.
The honest weighting
Lower than in equities, and for two compounding reasons: the underlying vol-spot relationship is less reliable, and the book generating the flow is small against the market absorbing it. Reading vanna as a primary driver here imports an equity model into a market whose participants are doing something else.
It belongs in the same category as charm — a mechanism worth understanding, not a level worth trading.