What is a gamma squeeze?

A gamma squeeze is what happens when enough traders buy call options on the same stock at the same time that the dealers who sold those calls are forced to buy the underlying stock to hedge — and the more the stock rises, the more they have to buy. It's a feedback loop hidden one layer below the regular stock market, and it's responsible for some of the most violent up-moves of the last decade.

01 — SectionThe mechanics in plain English

When you buy a call, someone has to sell it to you. That someone is almost always a market-making desk, not another retail trader. Desks don't want to bet on direction — they make money on the spread — so they hedge by buying shares of the stock. The number of shares they need to hold rises as the stock approaches and exceeds the strike price. That rate of change is called gamma. When call volume is massive and concentrated near the current price, gamma is high, and small price moves force big hedging adjustments.

02 — SectionGamma vs. short squeeze

A short squeeze is short sellers buying to cover. A gamma squeeze is options dealers buying to hedge. The two often happen on the same stock at the same time — that was the GameStop January 2021 setup — and the combination is what produces the truly parabolic moves. On their own, either can drive a 20–50% rally; together, they can drive 500%.

03 — SectionWhat to look for

• A surge in short-dated call volume, especially at strike prices just above the current spot.
• A rapidly rising call/put ratio (anything north of 3:1 on a high-volume day is notable).
• Open interest building at specific strikes — those become magnets and pin points.
• Implied volatility expanding faster than the stock is moving, signaling demand for upside.

04 — SectionHow it ends

Gamma squeezes unwind in two ways. The clean way: calls expire or get rolled, dealer hedges come off, and the stock drifts down as the forced buying turns into mechanical selling. The messy way: a single catalyst — a denial, a dilution, a guidance cut — collapses the call demand instantly and the entire hedge book unwinds in a session. Both are visible in hindsight; only the first is survivable for late entrants.