How to Read a GEX Heatmap: A Step by Step Guide
A gamma exposure heatmap shows net dealer gamma at every strike across every expiration at once, and reading the heatmap well is a matter of knowing which cells to ignore.
How do you read a GEX heatmap?
A gamma exposure heatmap places strikes on one axis and expirations on the other, colouring each cell by net dealer gamma at that intersection. Reading the heatmap means finding where intense colour clusters sit relative to current price, because clustered intensity marks the levels dealer hedging will actually defend.
Colour direction tells a trader which way hedging pushes, and colour intensity tells a trader how hard. A single bright cell on a far dated expiration matters far less than a vertical column of moderate cells stacked at one strike, because the column means several expirations defend the same price.
What do the colours on a gamma heatmap mean?
Positive net gamma cells, conventionally rendered green, mark strikes where dealer hedging dampens movement and pins price. Negative net gamma cells, conventionally rendered purple or red, mark strikes where dealer hedging amplifies movement and accelerates price away from the strike.
Which part of a GEX heatmap actually matters?
The rows nearest current price and the nearest two expirations carry almost all of the tradable information. Far dated columns look dramatic because open interest accumulates there over months, yet far dated gamma is small and produces very little hedging pressure today.
What is the biggest mistake when reading a heatmap?
The most expensive mistake is treating the brightest cell anywhere on the grid as the most important level. Brightness reflects raw exposure, while tradability depends on proximity to current price, on time remaining, and on whether liquidity supports the level at all.
Frequently asked questions
Does Obsidian publish a free GEX heatmap?
No. The Obsidian desk distributes no market data. Cipher members generate heatmaps inside the Cipher terminal using their own broker key under the BYOK model.
Why does a GEX heatmap change during the day?
Open interest updates daily, but gamma itself changes continuously with spot price and time remaining, so the same open interest produces a different heatmap through the session.
Are gamma heatmaps useful for swing trading?
Gamma heatmaps are most useful intraday and across a few sessions. For multi week holds, positioning shifts too often for a single heatmap read to remain relevant.