Positive gamma: option dealers' hedging tends to calm moves: they sell into rises and buy into falls, so the index often stays in a range.
The call wall often acts as resistance and the put wall as support.
Calls (+) Puts (−) Net SENSEX now
From the live option chain (nearest expiry, 15 strikes each side): gamma from Black-Scholes, open interest from the exchange. Assumes dealers are long calls and short puts; an estimate, not investment advice.
What is gamma exposure (GEX)?
An estimate of how much stock or futures option dealers must buy or sell to stay hedged when the index moves 1%, from each strike's gamma and open interest.
What does positive or negative GEX mean?
Positive: dealers' hedging works against the move (buy dips, sell rallies), which tends to calm the index. Negative: their hedging goes with the move, which can make swings bigger.
What are the call wall and put wall?
The strikes with the most call and put gamma. They often act as resistance and support for the day.