🗺️ Reading the GEX Heatmap

The Grid: Strikes × Expirations

The heatmap is a table where rows = strike prices (highest at top) and columns = expiration dates (nearest on the left). Each cell shows the GEX value for that strike/expiry combination.

💡 The nearest expiration (left-most column) usually has the highest gamma impact because gamma increases as expiration approaches — especially for at-the-money options.

Colors: Blue vs Green

Blue = Positive GEX (Calls)

Dealers are long gamma here. This level tends to act as a stabilizer — price often consolidates near it. Darker blue = stronger effect.

Green = Negative GEX (Puts)

Dealers are short gamma here. This level tends to amplify moves — price may accelerate through it. Darker green = stronger effect.

Near-zero cells are light/white. The further from zero, the darker the color. Intensity is scaled relative to the overall grid with outlier protection — so a single extreme cell doesn't wash out the rest of the heatmap.

🏅 Top-5 GEX Nodes

The heatmap automatically ranks the 5 cells with the largest absolute GEX values across the entire grid. Each is marked with a numbered badge — gold ① for the strongest, silver ② for second, bronze ③ for third, and muted ④ ⑤ for fourth and fifth.

💡 The #1 node represents the center of gravity for dealer hedging pressure. Price often gravitates toward it during the session, especially in positive GEX environments.

Blue #1 (positive) — Strong call wall. Tends to act as a major magnet above or at the spot price.
Green #1 (negative) — Strong put wall. Dealer hedging at this level may amplify moves if breached.
The sidebar shows the #1 Distance % for each ticker — how far the current spot price is from the top node.

The Current Price Row

The row closest to the current spot price is highlighted with a subtle marker showing the exact price. This lets you instantly see the GEX landscape around where the stock is actually at.

Row Totals (Right Side)

The rightmost area shows the total GEX per strike (sum across all expirations). This is useful for finding the overall strongest levels regardless of which specific expiry contributes the most gamma.

A strike with large total GEX across multiple expirations is a much more persistent level than one where GEX comes from a single expiry.

🔬 Fixed-Strike IV Badges

Key strikes (current price, King Strike, Gamma Flip) display a small IV badge showing the OI-weighted Call IV and Put IV at that strike, plus a trend arrow showing if IV is rising or falling over the last 30 minutes.

C:45%▲ — Call IV at this strike is 45% and rising. Increasing demand for options at this level.
P:52%▼ — Put IV at this strike is 52% and falling. Demand for puts at this level is declining.

These badges add observable market data to the GEX model. Learn more about this in the GEX Patterns page (Section 5: Fixed-Strike IV Confirmation).

Clicking a Cell — Contract Details

Click any cell to see a detailed popup with:

Individual call and put contract details (open interest, gamma, delta, IV)
Premium — notional value of open positions at that strike
Time comparison — how the GEX value changed over 1m, 5m, 15m, 1h, and 4h
Fixed-Strike IV History — Current call/put IV at this strike and how it changed over 5m, 15m, 30m, 1h, 2h, and 4h
Whether gamma was from the API or estimated via Black-Scholes (🧮)

💡 The time comparison is especially useful — a cell that was light 1 hour ago but is now dark means new positioning is building at that level. Pay attention to these shifts.

Greeks Modes: API vs BS

GammaBaba offers two gamma calculation modes:

📡 API — Uses gamma values directly from the market data API. More conservative, fewer contracts.
🧮 BS (Black-Scholes) — Estimates gamma for contracts missing API greeks using established pricing models. More comprehensive coverage, especially for less liquid strikes.

The default is BS mode. We recommend it because many valid contracts simply don't have API-provided greeks, and you'd miss important GEX levels without estimation.

GEX Scale: $1 vs 1%

Two scaling options for the GEX calculation:

$1 (per dollar move) — Standard GEX. How much hedging per $1 price change. Default.
1% (per 1% move) — Normalized GEX. Better for comparing tickers with different stock prices (e.g., SPY at $500 vs a $20 stock).

🔑 Key Takeaways

Blue (positive) = stabilizer / magnet tendency. Green (negative) = accelerator tendency.
The King Strike is the single strongest point of hedging pressure on the board.
Near-term expirations (left columns) have the most gamma impact.
Dark cells = high GEX magnitude, light/white = minimal exposure.
Click any cell for detailed contract breakdown, historical changes, and IV history.
Row totals show the aggregate strength of each strike across all expirations.
IV badges on key strikes show real-time vol demand — trend arrows show direction of change.
Use BS mode for the most complete picture of the GEX landscape.

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