Vanna & Charm · Foundations

Dealer Vanna & Charm, Explained

Gamma is the hedging flow everyone watches — the one that reacts to price. Vanna and charm are the two it misses: the flows that fire when volatility moves and when time passes.

A dealer hedges to stay delta-neutral, and that delta changes for three reasons, not one. Gamma is how delta moves with price. Vanna is how delta moves with implied volatility. Charm is how delta moves with the passage of time. Watch only gamma and you see a third of the hedging picture — and you miss the flows that quietly drive markets on days when price barely moves.

Vanna — the volatility flow

Vanna is why a quiet, drifting market can melt up for no obvious reason. When implied vol falls — say, after a feared event passes — the deltas on the protection dealers are short change, and they must buy the underlying to stay hedged. That buying lifts price even though nothing happened on the tape. It's the engine of the post-event vanna rally: vol down, dealers buy, market grinds higher.

Charm — the time flow

Charm is the delta decay of options as expiration approaches. As time passes, out-of-the-money options bleed delta and dealers re-hedge accordingly — a flow that builds steadily into expiration. In calm markets, charm tends to be supportive, contributing to the quiet upward drift that often shows up in the days before a big OPEX.

The flows gamma misses

The point of the tool is completeness. Dealer gamma tells you how hedging reacts to price; vanna and charm tell you how it reacts to vol and time. On a day when the index barely moves but vol drips lower into a Friday expiration, gamma sees nothing — while vanna and charm are quietly doing the buying. The tool maps net dealer vanna by strike and net dealer charm by strike so you can see where those flows are concentrated.

How it ties to the Nations suite

Vanna and charm complete the positioning picture that gamma starts. Pair them with the implied-vol tools — when the Option Window shows a broad vol crush, that's exactly the vol move that fires vanna flows; when an event in the Event Vol tool is about to resolve, the crush that follows is what drives the vanna rally. Positioning and price-of-vol, read together.

Educational content from Nations Indexes. Vanna and charm exposures are estimates of dealer positioning under a standard sign convention; they are regime heuristics, not precise flow models, and nothing here is investment advice.