Beyond the primary Greeks, dealers track second-order sensitivities that drive real hedging flows. Charm (delta decay) measures how delta changes as one day passes — critical for expiring options where delta can flip from 0.5 to 0 or 1 overnight. Vanna measures how delta changes when implied volatility shifts, and Volga (vega convexity) captures how vega itself responds to vol moves.

These matter because market makers hedge in these dimensions, creating feedback loops into spot and vol markets.

Charm: ∂Δ/∂t — accelerates pinning near expiry
Vanna: ∂Δ/∂σ — links skew to spot flows
Volga: ∂ν/∂σ — why OTM wings get bid in vol spikes

Greek	Measures	Typical Trigger
Charm	Delta change per day	Expiry week
Vanna	Delta change per 1% vol	Vol crush events
Volga	Vega change per 1% vol	Tail-risk hedging