What is negative gamma?
Negative gamma describes a market state in which options dealers, in aggregate, are short gamma — meaning their hedging requirements force them to trade with the market’s direction: buying as prices rise and selling as prices fall. That pro-cyclical hedging amplifies moves instead of dampening them, which is why negative gamma regimes are associated with trending price action, larger intraday swings, and elevated volatility.
How does dealer hedging change under negative gamma?
A dealer who is short options must keep the position delta-hedged as the market moves. Short gamma means the position’s delta moves against the dealer: a rally makes them shorter, so they must buy; a selloff makes them longer, so they must sell. Every hedge adjustment pushes in the same direction the market was already going. Under positive gamma the arithmetic flips — dealers sell rallies and buy dips, and their hedging acts as a stabilizer. Same mechanics, opposite market character.
What causes the market to flip into negative gamma?
Dealer gamma is the mirror of customer positioning. When customers are net buyers of options — puts for protection in a selloff, or speculative calls in a mania — dealers end up net short those options and short gamma. Selloffs are the classic trigger: put demand surges, and the market often flips negative right as prices fall through the level where aggregate dealer gamma crosses zero (SpotGamma calls this the Volatility Trigger). Below that flip point, hedging switches from stabilizing to amplifying, which is why volatility often accelerates through it.
How do traders know if the market is in negative gamma?
You can’t observe dealer books directly — every platform estimates. The standard public approach applies a fixed assumption to open interest (dealers short all calls, long all puts, or a variant), which is a rough proxy that often mislabels the regime. SpotGamma’s SGOI instead estimates how market makers and buyside participants are actually positioned, per stock and in aggregate, and its HIRO indicator shows the resulting hedging flow in real time — so you can see the amplification or dampening as it happens rather than inferring it. See also: gamma exposure (GEX) explained.
What does negative gamma mean for trading?
Regime awareness, not a signal. In negative gamma conditions, moves tend to extend and reversals are sharper — momentum strategies find more follow-through and mean-reversion gets punished. In positive gamma conditions, ranges tighten around large strikes and fading extremes works better. Knowing which regime is active — and where the flip point sits — is context that changes how the same price action should be read.
Last updated: August 2026 — Published by SpotGamma. For how positioning platforms compare, see our gamma exposure tool comparison.