How to read gamma levels on a chart

The levels at a glance

Owl Mastery publishes four gamma levels for each stock and index with options data, plus the close. It computes them once a day after the US close, and the three strike levels use every strike.

Level	How Owl Mastery computes it	What it may mean
Call resistance (call wall)	The strike with the largest net gamma exposure	A place where a rally may stall
HVL	The strike where the running sum of net exposure, from the lowest strike up, is lowest	The line between the negative-gamma and positive-gamma sides
1-day range	Spot ± spot × IV30 / √252	The size of a one-standard-deviation day
Put support (put wall)	The strike with the most negative net gamma exposure	A place where a decline may slow, or speed up once broken

Net exposure is dollars of delta-hedging exposure per $1 move, summed across expiries, with calls positive and puts negative. Call resistance is also the gamma wall, the strike with the largest gamma times open interest, so the levels table shows both names in one row. IV30 is the implied volatility of the listed expiry closest to 30 trading days out. The methodology page has every formula, and the gamma exposure article explains the measure.

How to read gamma levels, step by step

1. Check the date. The levels come from the previous close and apply to the next session. The levels table names the close they belong to, and says so when the levels are older than the latest close.
2. Find the close. The table lists the levels and the close together, highest first, with each level's distance from the close in percent.
3. Check the side of the HVL. Above the HVL, net exposure is positive on balance and hedging may damp moves. Below it, net exposure is negative on balance and hedging may add to moves. The positive vs negative gamma article explains why.
4. Locate the walls. Note where call resistance and put support sit. The close often lies between them, but it can sit above call resistance or below put support. Call resistance is also the gamma wall.
5. Size the day. Compare each level's distance with the one-day range. Levels inside the range are within reach of a one-standard-deviation day. Levels outside it would take a larger move.
6. Look again after the next close. The levels change daily as positions open, close and expire.

A worked example

The ladder below is illustrative, not live data. It shows a stock that closed at $100 with an IV30 of 30%.

Level	Price	From close
Call resistance and gamma wall	110.00	+10.00%
1-day range high	101.89	+1.89%
Close	100.00
1-day range low	98.11	-1.89%
HVL	97.50	-2.50%
Put support	95.00	-5.00%

• The close is above the HVL, on the positive-gamma side, where hedging may damp moves.
• The HVL is 2.5% below, outside the one-day range, so a close below it would take more than a one-standard-deviation day.
• Call resistance is 10% above and put support 5% below, both well outside the one-day range.
• The gamma wall is call resistance, so the two names share a row.

Read together, the levels describe a stock on the calmer side of its HVL with room before either wall. They do not say which way it moves next.

Reading the levels on a price chart

On the Owl Mastery dashboard, which needs a free account, the price chart marks call resistance with a solid green line, the HVL with a solid blue line and put support with a solid red line. A shaded band with dotted edges marks the one-day range. Dashed lines mark the last close and the previous close. Chips above the chart read CR, HVL, PS and 1D range with their values, and a chip dims when its level falls outside the drawn price range.

To draw the levels on another charting tool, add a horizontal line at each price from the levels table, and redraw them after each close. The ticker pages for SPX, AAPL and NVDA list the latest levels with their distances from the close.

Common mistakes

• Treating levels as walls. Price can trade through any level. The names describe where hedging may change, not where price has to stop.
• Reading positive gamma as bullish. The regime describes how hedging reacts to a move in either direction, not which direction comes next.
• Mixing sources. Another site's gamma flip or call wall may use a different method. Compare definitions before you compare numbers.
• Using old levels. Levels from an earlier close can be far from today's positioning.

Limits of gamma levels

• A model of dealers. Every level rests on the assumption that dealers are long the calls and short the puts their customers trade. Open interest does not show who holds each side.
• Once a day. The levels come from the options open interest for that day and stay fixed through the next session. Owl Mastery keeps the latest snapshot only, with no history of past levels.
• Tendencies, not forecasts. News, earnings and broad market flows can outweigh hedging at any level.