Vanna vs Charm: The Two Greeks That Move Markets Quietly

Vanna is how an option's delta changes when implied volatility changes — formally ∂²V/∂S∂σ. If IV drops 1 vol point, every call delta in the chain shifts, and the dealer who hedged at the old delta now has the wrong hedge. Vanna captures that mismatch.

Charm is how an option's delta changes when time passes — formally ∂²V/∂S∂t. Even if spot and IV don't move at all, the delta of every option drifts toward its terminal value (0 for OTM, ±1 for ITM) as expiration approaches. Charm captures that drift.

Vanna becomes the dominant hedging flow when implied volatility moves but spot doesn't move much. The clearest example is the post-event IV crush: an FOMC announcement, an earnings print on a mega-cap, a CPI release. The catalyst resolves, IV across the chain compresses, and dealers across the street are suddenly holding "wrong" hedges. They rebalance — usually by buying SPX or QQQ — which is why the canonical reaction to a "no-news" Fed day is a slow grind higher in the cash session after the dust settles.

Vanna also dominates in a vol shock. A spike in VIX disproportionately moves put deltas; dealers short index puts must sell SPX to rebalance, which adds fuel to the decline. This is the mechanism behind the "vol up, spot down" feedback loop that defines stressed sessions.

Charm dominates when spot and IV are both relatively calm and the clock simply keeps ticking. The most reliable charm regime is the SPX afternoon on a positive-gamma day with no overnight catalyst on the schedule. Out-of-the-money call deltas decay toward zero, and dealers who were short those calls need to reduce their long SPX hedge — they sell SPX. Out-of-the-money put deltas decay toward zero, and dealers who were long those puts need to reduce their short SPX hedge — they buy SPX.

The net effect is usually a slow drift toward the largest open-interest strike. This is the mechanical explanation for the well-known "afternoon drift higher into close" pattern on quiet positive-gamma days.

The week of monthly options expiration is where vanna and charm both peak at once. As Friday approaches, charm accelerates the delta decay on every position dealer-side. If IV also moves materially during the week (a CPI print, a Fed meeting, an earnings cluster), vanna re-stacks the hedge on top of the charm drift. The result is the "OPEX pin" — SPX repeatedly closing within a few dollars of a heavily-strikes-loaded round number on the third Friday.

After OPEX, both vanna and charm flows reset against a much smaller forward book, which is why post-OPEX Mondays are statistically more volatile than the average Monday.

In the Greeks tab, the VEX chart shows net dealer vega, and the vanna/charm strike-by-strike profiles are available as overlays. The most-watched vanna and charm levels (the strikes with the largest absolute exposure on each greek) are surfaced as walls in the Daily Levels tab. On the TradingView extension and Pine indicator, vanna and charm levels are available as optional secondary lines.

Watching them is most useful on slow, drift-prone afternoons — exactly when the market looks like nothing is happening, which is usually when these two greeks are doing the most work.