📊 What is VEX?
VEX — short for Vanna Exposure — measures the total dollar-weighted vanna that dealers hold across all strike prices for a given underlying asset.
While GEX captures how dealer hedging responds to price movement, VEX captures how dealer hedging responds to changes in implied volatility (IV).
Together, GEX and VEX provide a more complete picture of the hedging forces that shape market behavior.
🧱 Building Blocks: What is Vanna?
Vanna Defined
Vanna measures how much an option's delta changes when implied volatility changes by 1%.
Vanna = ∂Delta / ∂IVIf gamma is the link between price and delta, vanna is the link between volatility and delta.
Why Vanna Matters
When IV changes — which happens constantly throughout the trading day — the delta of every option shifts. This forces dealers to re-hedge, creating buying or selling pressure in the underlying. This effect is separate from and additive to gamma hedging. On any given day, a dealer must adjust their hedge for:
- Price movement (gamma effect)
- IV movement (vanna effect)
Both adjustments create real order flow in the market.
⚙️ How VEX is Calculated
At each strike price, VEX is calculated as:
Strike VEX = Vanna × Dealer Position × 100 × Spot Price × IVLike GEX, the true sign depends on whether the dealer is long or short the option:
- Dealer is long → positive (+) VEX
- Dealer is short → negative (−) VEX
NET VEX is the sum of all individual strike VEX values.
🔑 Vanna Sign and OTM Behavior
- OTM calls have positive vanna — when IV rises, their delta increases
- OTM puts have positive vanna — when IV rises, their delta (absolute value) also increases
- ITM options tend to have negative vanna
Since most trading activity occurs in OTM options, it's common for VEX to be predominantly positive across most strikes, especially when put and call activity are both concentrated in OTM strikes.
💡 If you see a VEX heatmap where nearly all values are positive, this is normal and expected in many market conditions.
📈 Interpreting VEX
The IV-Price Feedback Loop
- Price falls → IV typically rises (fear increases, hedging demand spikes)
- Price rises → IV typically falls (complacency returns, hedging unwinds)
As with GEX, the interpretations below assume that dealer positioning matches the inference from open interest data — the most common case in practice.
Positive NET VEX
| IV Movement | Dealer Response | Market Effect |
|---|---|---|
| IV falls (market calms) | Dealers buy underlying | Supports rally |
| IV rises (market panics) | Dealers sell underlying | Accelerates selloff |
Positive Market VEX tends to act as a tailwind for rallies and a headwind for declines — but only through the IV channel, and only when dealer positioning aligns with the inference. When markets are calm and IV is compressing, positive VEX creates a steady bid that supports prices. When fear spikes and IV expands, positive VEX creates additional selling pressure.
Negative NET VEX
| IV Movement | Dealer Response | Market Effect |
|---|---|---|
| IV falls | Dealers sell underlying | Dampens rally |
| IV rises | Dealers buy underlying | Cushions decline |
Negative VEX is less common but can occur when ITM options dominate or when unusual positioning exists.
🔄 GEX + VEX: Confluence Analysis
The most powerful analysis comes from reading GEX and VEX together at the same strike prices.
Same-Direction Confluence
Both GEX and VEX positive at a strike: GEX provides pinning/stabilization from price movement. VEX provides additional buying support if IV falls. This is the strongest support/resistance configuration — highest-probability reversal zone.
Both GEX and VEX negative at a strike: GEX amplifies price movement. VEX adds selling pressure if IV rises. This is the most dangerous configuration — a "double acceleration" zone where cascading moves can trigger.
Opposing Confluence
GEX negative, VEX positive: GEX pushes for volatility expansion; VEX may provide cushion if IV peaks and starts to decline. Outcome depends on IV direction — an uncertain zone. Often seen at major support levels during selloffs.
GEX positive, VEX negative: GEX stabilizes price; VEX creates headwind for rallies as IV falls, making this a "sticky" resistance level.
🧭 Key VEX Levels
+VEX Strike
The strike with the largest positive VEX. This is where the strongest IV-driven buying support exists. When IV compresses, this level acts as an additional magnet.
−VEX Strike
The strike with the largest negative VEX. This level may resist rallies or provide unexpected support during selloffs, depending on IV direction.
📋 VEX Quick Reference
| Condition | IV Falls | IV Rises |
|---|---|---|
| +VEX | Dealers buy (bullish) | Dealers sell (bearish) |
| −VEX | Dealers sell (bearish) | Dealers buy (bullish) |
| NET VEX | Calm Market (IV ↓) | Panic (IV ↑) |
|---|---|---|
| Positive | Supports price | Pressures price lower |
| Negative | Pressures price lower | Supports price |
⚠️ Limitations of VEX
- Vanna is a second-order Greek. Its magnitude is typically smaller than gamma's impact, meaning GEX usually dominates VEX in terms of market effect.
- VEX changes faster than GEX. Because vanna is sensitive to both price and IV simultaneously, VEX levels can shift more rapidly throughout the day.
📚 Key Takeaways
- VEX measures dealer hedging driven by IV changes, separate from GEX's price-driven hedging
- Positive VEX → IV decline creates buying support; IV spike creates selling pressure
- It's normal for most VEX values to be positive when OTM options dominate activity
- GEX/VEX confluence at the same strike creates the highest-conviction levels
- Same-direction confluence amplifies the effect; opposing confluence creates uncertainty
- VEX is most impactful during high-IV transitions (vol crush after events, or fear spikes)
- Market VEX, like Market GEX, is inference, not direct observation. Use it as a structural map; confirm with price action and IV behavior.
📘 Note: VEX Follows the Same Market vs. Dealer Distinction
As with GEX, the dealer-hedging dynamics described in this chapter operate most precisely when actual dealer positions are known (Dealer VEX). What GEXFlow currently provides is Market VEX — vanna exposure inferred from open interest data.
Market VEX is a useful map of IV-sensitive positioning, but, like Market GEX, it is an inference rather than a direct observation of dealer intent.
Direct Dealer VEX observation is planned for a future Pro tier release.