Gamma exposure

Why gamma exposure matters

When market makers sell options, they hedge the resulting delta by trading the underlying — buying or selling the index (via futures) as price moves, to stay flat. Gamma exposure (GEX) measures how large that hedging flow is likely to be at each strike, and in which direction it pushes price.

When dealers are net long gamma (positive GEX), hedging works against the move — they sell into rallies and buy into dips — which tends to compress volatility and pin price near high-open-interest strikes. When dealers are net short gamma (negative GEX), hedging flows with the move instead, amplifying it. The point where net GEX crosses zero is the zero-gamma flip — the level where the market's structural bias switches from dampening to amplifying.

How to read this chart

Each bar is the net gamma exposure at one strike for the nearest expiry. Green bars (positive) sit above the zero line — dealers are estimated long gamma there. Red bars (negative) sit below — dealers are estimated short. The marker shows the current zero-gamma flip level relative to spot.

• Spot above the flip level — the market is in a long-gamma regime; moves tend to get absorbed.
• Spot below the flip level — the market is in a short-gamma regime; moves tend to extend further than they otherwise would.
• Large bars near spot — strikes with heavy open interest, more likely to act as a magnet (positive) or an accelerant (negative) as expiry approaches.

Methodology & data

NSE and BSE don't publish implied volatility directly, unlike Deribit for BTC, so IV here is back-solved from each strike's last-traded price via Black-Scholes, then gamma is computed from that back-solved IV. Dealer positioning itself is never directly observable from public data, so this assumes dealers are net short calls and net long puts relative to customer flow — the same convention every public GEX tool uses. Treat it as a structural read on likely hedging pressure, not a certainty.