📚 Stock Market Glossary
Clear, beginner-friendly explanations, real-world analogies, and visual formulas for key stock market terminology.
GEX (Gamma Exposure & Market Maker Delta Hedging)
Trading & Market💡 Key Takeaway: A quantitative options metric quantifying aggregate dealer gamma positioning to predict whether automated market maker delta hedging will dampen (+GEX) or amplify (-GEX) equity price volatility.
Shock Absorber vs Rocket Booster: Positive GEX acts like a soft mattress cushioning every bounce; Negative GEX acts like an avalanche where every falling rock triggers thousands more.
😎 10-Second Show-off Pro Tip for Friends!
😎 Show-off Tip: Tell your trading group, 'The market feels sticky because we are deep in Positive GEX territory; option dealers are continuously selling into rallies and buying every dip to rebalance delta!'
📖 Beginner-Friendly Explanation
STEP 1
Core Concept & Meaning
Gamma Exposure (GEX) measures the dollar sensitivity of aggregate option market maker delta hedges relative to changes in the underlying index price.
Options dealers remain delta-neutral by continuously rebalancing underlying equities or futures. Because gamma dictates how fast delta changes, aggregate dealer positioning dictates whether institutional flow acts as a market stabilizer or an accelerator.
STEP 2
Why It Matters & Mechanism
- Positive GEX (Volatility Dampener): Dealers are long gamma. As the market rises, dealers sell stock; as it falls, dealers buy stock, suppressing market volatility.
- Negative GEX (Volatility Accelerator): Dealers are short gamma. As prices drop, dealers must aggressively sell into market weakness, accelerating drawdowns and flash crashes.
- The Gamma Flip Level: The exact underlying index price where aggregate net GEX transitions from positive to negative, marking sudden volatility spikes.
STEP 3
Practical Investment Tips & Pitfalls
When major indices trade above the Gamma Flip in Positive GEX, range-bound mean-reversion strategies work best. If the index breaks below the Flip into Negative GEX, hedge aggressively against cascade selloffs.
📊 Option Contract GEX Calculation Formula
Contract GEX ($) = Option Gamma (Γ) * Open Interest (OI) * Spot Price (S) * Contract Multiplier (100) * Dealer Sign (+/-)
• Summed across all strikes and expirations to determine Aggregate Net GEX dollar exposure
⚖️ Key Comparison at a Glance
| Regime | Positive GEX Regime (Long Gamma) | Negative GEX Regime (Short Gamma) |
|---|---|---|
| Dealer Hedging Action | Sell into rallies / Buy into dips (Mean-reverting) | Buy into rallies / Sell into selloffs (Trend-amplifying) |
| Market Volatility (VIX) | Low realized volatility and compressed intraday ranges | High realized volatility, wide swings, and tail risks |
| Price Action Dynamic | Orderly upward grind, sticky support levels | Fast directional cascades, gap downs, sharp air pockets |
| Winning Strategy | Dip-buying, covered calls, short volatility | Trend following, long protective puts, raising cash |
📌 Practical Market & Real-World Example
When the S&P 500 breached its 5,000pt Gamma Flip strike into Negative GEX, dealer delta hedging triggered mandatory equity dumping, compounding a rapid 4% index drop.