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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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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['net_gex']}")
print(f"Gamma Flip: {data['gamma_flip']}")

Full API docs → Try in playground →

Get GEX via API

Single-expiry GEX is included on the free Starter plan (10 requests/day). Full-chain GEX across all expirations available on Growth (2,500/day) and Alpha (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.

Want to compute GEX yourself from raw data? See our open-source walkthrough with Python code: GEX Explained on GitHub

What Is Gamma Exposure (GEX)?

Gamma exposure — commonly abbreviated GEX — measures the total amount of options gamma that market makers and dealers hold across every strike price for a given underlying asset. Gamma itself is a second-order Greek: it tells you how quickly a dealer’s delta (directional exposure) changes as the underlying price moves by one dollar. When you aggregate that sensitivity across all open options contracts, you get a dollar-weighted map of where dealers will be forced to hedge — and in which direction.

Think of GEX as a pressure map of the options market. Each strike with significant open interest exerts a gravitational force on the underlying. Strikes where dealers are long gamma act like shock absorbers: as the stock moves toward them, dealers hedge by buying dips and selling rallies, dampening volatility. Strikes where dealers are short gamma do the opposite — dealers must sell into sell-offs and buy into rallies, amplifying moves. The aggregate balance between these forces determines whether the market is in a mean-reverting or trending regime.

Why Gamma Exposure Matters Near Expiration

Gamma increases exponentially as options approach expiration — a phenomenon known as “gamma acceleration.” An at-the-money option with one day to expiry can have 5–10x the gamma of the same strike with 30 days remaining. This means the hedging flows driven by GEX become dramatically larger in the final days before expiration, especially around weekly and monthly OPEX dates. For index ETFs like SPY and QQQ, which have trillions in notional options exposure, these flows can single-handedly dictate intraday price action.

The practical consequence is that the gamma flip point — the strike where net dealer GEX crosses from positive to negative — becomes a hard regime boundary near expiration. When SPY trades above the flip point in the last 48 hours before OPEX, intraday ranges tend to compress as dealers suppress moves. When it trades below, ranges can expand 2–3x as dealers amplify directional momentum. Traders who ignore this dynamic are effectively trading blind during the most mechanically-driven sessions of the week.

How to Use the FlashAlpha GEX Tool

Enter any optionable ticker into the tool above and select an expiration date to see the full gamma exposure profile by strike. The horizontal bar chart shows call GEX (positive, green) and put GEX (negative, red) at each strike, with the net GEX value determining the overall direction. Key levels are highlighted automatically: the gamma flip point, the call wall (strike with the highest positive GEX, which acts as a magnet), and the put wall (strike with the most negative GEX, which acts as a floor or acceleration zone if breached).

For systematic workflows, the same data is available via the FlashAlpha Lab API — every chart on this page is powered by the same endpoint you can call programmatically. Pull GEX data into your Python scripts, spreadsheets, or trading bots with a single API call. Free-tier accounts get single-expiration lookups with no credit card required; Growth plans unlock aggregated all-expiration views and historical snapshots for backtesting.

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