Question 1

What is gamma exposure (GEX)?

Accepted Answer

Gamma exposure (GEX) estimates how much stock options dealers must buy or sell to stay hedged as the price moves. It is computed from options open interest and each option's gamma at every strike. When dealers are net long gamma their hedging leans against moves; when they are net short gamma it chases moves.

Question 2

What are gamma walls in options?

Accepted Answer

A gamma wall is a strike with unusually large options open interest, where dealer hedging is concentrated. As price approaches it, hedging can slow the move (a wall) or pull price toward the strike (a magnet). Call-heavy strikes above price usually act as resistance and put-heavy strikes below as support while dealers are long gamma.

Question 3

Where is SPY's gamma wall today?

Accepted Answer

SPY's gamma walls change every session as open interest moves. The table below shows today's nearest wall above price, the nearest wall below, the largest wall overall and the dealer gamma regime, with the time of the snapshot. The full list for 200+ stocks is on the free gamma page.

Question 4

What does negative gamma mean for the stock market?

Accepted Answer

Negative gamma means options dealers are, on balance, short gamma, so their hedging buys as prices rise and sells as prices fall. That hedging adds to moves instead of dampening them, which is why negative-gamma sessions tend to have wider ranges and more trending intraday action. It describes conditions, not direction.

Question 5

What is the gamma flip level?

Accepted Answer

The gamma flip is the price at which estimated net dealer gamma changes sign from positive to negative. Above it, dealer hedging tends to dampen moves; below it, hedging tends to amplify them. It is a model estimate that shifts as open interest and price change.

Question 6

How do 0DTE options affect SPY?

Accepted Answer

Zero-days-to-expiration (0DTE) options expire the same day, so their gamma is very high near the money and their hedging needs change fast. Large 0DTE positions can create intraday walls and magnets that matter for hours, then vanish at the close. Their effect is strongest near heavily traded strikes late in the session.

Question 7

How do I read a volume profile (POC, value area)?

Accepted Answer

A volume profile shows how many contracts or shares traded at each price during a session. The point of control (POC) is the price with the most volume, and the value area is the range around it that holds 70% of the session's volume. Traders use the POC and the value-area high and low as reference levels.

Question 8

What is the expected move and how is it calculated?

Accepted Answer

The expected move is the price range the options market is pricing for a stock by a given expiration. A common estimate is the price of the at-the-money straddle (the call plus the put at the strike nearest the current price). The straddle prices the average size of the move, a little under one standard deviation (about 0.8 SD); it is a range, not a target.

Question 9

How often does SPY stay within the VIX expected move?

Accepted Answer

More often than the VIX implies. From January 2006 to November 2026 (5,240 trading days), SPY closed within the one-day, one-standard-deviation move implied by the previous close's VIX on 80.6% of days, against the 68.3% a fair estimate would give, and within two standard deviations on 98.1%. The typical day moved about half the implied amount. The gap narrows when the VIX is high: above 30, 69% of days stayed inside.

Question 10

What is dealer hedging?

Accepted Answer

Dealer hedging is the buying and selling of the underlying stock or futures that options market makers do to stay market-neutral after taking the other side of customer trades. Because it is driven by option greeks rather than opinion, it creates predictable flows around large strikes and expirations.

Question 11

Call wall vs put wall: what's the difference?

Accepted Answer

The call wall is the strike above the current price with the most call open interest, and the put wall is the strike below with the most put open interest. In positive dealer gamma, the call wall often acts as resistance and the put wall as support. Both move as open interest changes.

Question 12

What is IV rank?

Accepted Answer

IV rank shows where a stock's current implied volatility sits within its own range over a lookback period, usually one year: 0 means the lowest IV of the period and 100 the highest. It tells you whether options are cheap or expensive relative to that stock's history, not relative to other stocks.

Question 13

How do options market makers move prices near expiration?

Accepted Answer

Near expiration, gamma at strikes close to the price becomes very large, so market makers' hedges change quickly with small price moves. In positive gamma this hedging can pin price near a heavily traded strike; in negative gamma it can accelerate moves. After expiration, those hedges are unwound and the effect disappears.

Learn: how options positioning moves stocks