Gamma Squeeze Explained

A gamma squeeze is what happens when dealer hedging turns a wave of call buying into a self-reinforcing rally, independent of any short sellers.

What a gamma squeeze is

A gamma squeeze happens when a wave of call buying forces the dealers who sold those calls to buy more and more of the underlying stock just to stay hedged, and that hedging-driven buying pushes the stock price higher, which then forces even more hedging-driven buying. It's a self-reinforcing loop rooted purely in options mechanics, not in any change to the company's fundamentals.

The dealer hedging feedback loop

When a market maker sells a call option, they typically hedge by buying some shares of the underlying stock, sized to the option's delta (see the dedicated delta guide). As the stock rises toward or past the strike, that call's delta climbs toward 1.00, meaning the dealer needs to hold more shares per contract to stay hedged — this is the gamma effect, the acceleration of delta itself. The dealer is short gamma on the calls they sold, so rising prices force them to keep buying.

If enough call buying is concentrated in a short window and a small number of strikes, common with heavily promoted or highly speculative names, that dealer buying can become a meaningful share of total trading volume, adding real upward pressure that has nothing to do with anyone's view on the company's earnings or growth.

How it differs from a short squeeze

A short squeeze is driven by short sellers being forced to buy back borrowed shares as the price rises against them, to cap losses or meet a margin call. A gamma squeeze is driven by market makers and other option sellers hedging a derivatives position, regardless of whether anyone is short the stock at all. The two can happen together and reinforce each other — call buying pushes the price up, which triggers dealer hedging, which triggers short covering, which pushes the price up further — but they're mechanically distinct phenomena with different participants at the center.

Real-world flashpoints

Gamma squeezes tend to surface in stocks with a relatively small float, heavy options activity concentrated in near-dated, out-of-the-money calls, and a sudden surge of buying interest. The most widely cited case is the 2021 retail-driven surge in a handful of heavily shorted names, where options positioning and short covering compounded each other (covered in more depth in the dedicated GameStop history guide). Smaller, less dramatic versions of the same dynamic show up periodically in other high-volatility, high-options-volume names.