Using Vanna and Charm for Hedging
Gamma explains what happens when price moves. Vanna and charm explain what happens when it does not — when implied volatility bleeds lower or time simply passes. Those flows drive a surprising share of the quiet grind higher into monthly expirations.
Vanna: delta that changes with volatility
Vanna measures how an option's delta shifts when implied volatility moves. As IV falls after an event, dealer deltas on short puts shrink and hedges are unwound by buying back shares — the mechanical bid behind post-event drift higher.
Charm: delta that changes with time
Charm is delta decay per unit of time. Out-of-the-money options bleed delta as expiration approaches, forcing dealers to unwind hedges even with price unchanged. Charm flow clusters into Thursday and Friday of monthly expiration weeks.
- Vanna is strongest with elevated IV and heavy OTM put open interest.
- Charm dominates the last two sessions before a large expiration.
- Both flows are directional in aggregate even though neither is a forecast.
Building a hedge around them
If your book is short vega into a vol-crush event, expect vanna flows to lift spot; a short call spread at the Call Wall is a cheaper hedge than shorting shares. Into monthly expiry, charm-driven support argues for widening put spreads rather than closing them early.
Where the platform shows this
The Greeks panel on the Gamma page surfaces net vanna and charm alongside gamma so you can tell whether today's drift is price-driven or flow-driven.
Key takeaways
- Vanna converts IV moves into hedging flow; charm converts time passing into it.
- Both are strongest into monthly expirations and after volatility events.
- Use them to choose the cheapest hedge, not as standalone entry signals.
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Educational content only. Options involve substantial risk and are not suitable for every investor. Nothing here is financial advice.