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Gamma Exposure (GEX)

See where dealers must hedge. GEX reveals the strike-level gamma that drives intraday support, resistance, and volatility regime.

Gamma exposure analysis shows dealer positioning by strike price. Enter any symbol to see net GEX, the gamma flip point, and call/put walls — updated with live options data.

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Symbol

Expiry

What can you do with GEX?

Find the Flip Point

The strike where net GEX crosses zero. Above it, dealers dampen moves. Below it, they amplify them. A critical level for day traders.

Support & Resistance

Strikes with large positive GEX act as magnets — dealers buy dips and sell rallies around them, creating mean-reverting zones.

Volatility Regime

Positive net GEX = low-vol, range-bound. Negative net GEX = trending, volatile. Screen the entire market for regime shifts.

Get this via API

curl

# Single expiry (free tier)
curl -H "X-Api-Key: YOUR_API_KEY" \
  "https://lab.flashalpha.com/v1/exposure/gex/SPY?expiration=2026-03-07"

# All expirations (Growth+ tier)
curl -H "X-Api-Key: YOUR_API_KEY" \
  "https://lab.flashalpha.com/v1/exposure/gex/SPY"

Python

import requests

r = requests.get(
    "https://lab.flashalpha.com/v1/exposure/gex/SPY",
    params={"expiration": "2026-03-07"},  # yyyy-MM-dd
    headers={"X-Api-Key": "YOUR_API_KEY"}
)
data = r.json()
print(f"Net GEX: {data['netGex']}")
print(f"Flip Point: {data['flipPoint']}")

Full API docs → Try in playground →

Get GEX via API

Single-expiry GEX is included on the free Starter plan (5 requests/day). Full-chain GEX across all expirations available on Growth (1,000/day) and Pro (unlimited).

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How Gamma Exposure Is Calculated

Gamma exposure quantifies the dollar value of shares dealers must trade to maintain delta-neutral positions as the underlying moves. For a single option contract:

$$\text{GEX}_i = \Gamma_i \times OI_i \times 100 \times S^2 \times 0.01$$

Where:

$\Gamma_i$ is the option's gamma (second derivative of price with respect to underlying)
$OI_i$ is the open interest at that strike
$S$ is the current underlying price
The factor $100$ converts to shares per contract, and $0.01$ normalizes for a 1% move

Net GEX and the Dealer Convention

Dealers (market makers) are assumed to be short calls and long puts when retail buys them. Therefore:

$$\text{Net GEX} = \sum_{i} \text{GEX}_{i}^{\text{call}} - \sum_{i} \text{GEX}_{i}^{\text{put}}$$

Call gamma is positive for dealers (they are short the call, so they hedge by buying when price rises). Put gamma is negative (they are long the put, so they sell when price falls). The subtraction reflects this dealer-centric sign convention.

The Gamma Flip Point

The gamma flip point is the strike price where cumulative net GEX transitions from positive to negative:

$$S_{\text{flip}} : \sum_{K_i \leq S_{\text{flip}}} \text{Net GEX}_i \approx 0$$

Above this level, dealers are net long gamma and their hedging suppresses volatility. Below it, they are net short gamma and their hedging amplifies moves.

Gamma and the Black-Scholes Model

Under Black-Scholes, gamma for a European option is:

$$\Gamma = \frac{\phi(d_1)}{S \sigma \sqrt{T}}$$

Where $\phi(d_1)$ is the standard normal PDF evaluated at $d_1$, $\sigma$ is implied volatility, and $T$ is time to expiration. Gamma is highest for at-the-money options near expiration — which is why 0DTE options create massive GEX concentrations.

Why GEX Matters for Traders

Institutional research from SqueezeMetrics and academic work by Bouchaud & Bonart (2018) demonstrate that dealer hedging flows create measurable price impact. GEX is not a predictive signal — it's a structural one. It tells you the rules of the game for that day.

Expiration Filtering

Near-dated options contribute disproportionately to GEX because gamma scales as $\frac{1}{\sqrt{T}}$. Our API supports filtering by expiration date so you can isolate 0DTE gamma (which drives intraday moves) from longer-dated positioning.

Limitations

Dealer assumption — GEX assumes dealers are short calls and long puts. In practice, some OI is inter-dealer or institutional hedging, which may have different sign conventions.
OI is T-1 — open interest is reported end-of-day by the OCC and reflects the previous session's close.
Not a crystal ball — GEX describes the mechanical hedging landscape, not future direction. Use it alongside price action, not as a standalone signal.