SPX Gamma Exposure History
SPX gamma exposure history for options and volatility research
Options and volatility researchers need years of index dealer gamma exposure to study regime shifts, tail risk and volatility clustering. Index data elsewhere may start only in late 2025, e.g. Databento Core Indices history from 7 December 2025 as of October 2026. FinzData provides point-in-time SPX gamma exposure from January 2010 to October 2026 with the 17:00 New York value used for next-day analysis.
What SPX gamma exposure measures
SPX gamma exposure measures the net gamma held by dealers across S&P 500 options. When dealers are short gamma they must hedge by buying when the index rises and selling when it falls, which can amplify moves. When dealers are net long gamma the hedging flow is dampening.
Gamma exposure is not a directional bet. It is a measure of convexity and the size of the hedging impulse that dealers are likely to generate the next day. Researchers use it to study volatility regimes, not to predict up or down.
FinzData publishes point-in-time gamma exposure for SPX, NDX, RUT, VIX, XSP, DJX and 11,209 tickers including single stocks and ETFs since January 2010. Values are stamped at 17:00 New York and are not revised retroactively.
FinzData study Jan 2010 to Oct 2026
Using over 4,221 sessions from January 2010 to October 2026 with the 17:00 New York point-in-time value, next-day SPX behaviour differs markedly after net short gamma closes versus net long gamma closes.
Short gamma predicted size, not direction. Past behaviour is not a forecast.
| Next-day outcome | After net short gamma close | After net long gamma close |
|---|---|---|
| Annualised volatility | 24.5% | 13.5% |
| Average absolute move | 1.08% | 0.52% |
| Days with move > 2% | 13.0% | 1.9% |
| Sessions with move > 3% | 72 of 88 | 16 of 88 |
72 of 88 sessions with moves over 3% followed a short-gamma close. Dealers were short gamma on 97% of sessions 20 Feb - 7 Apr 2020 and 81% of 2022 through mid-October, periods widely studied for volatility regimes.
Call wall, put wall and gamma flip
The call wall is the strike with the largest call gamma and the put wall the strike with the largest put gamma; they are concentrations of open interest that dealers hedge around. A call wall at a strike can pin the index as dealers hedge around that level. A put wall can act as support during selloffs.
The gamma flip is the index level where dealers' net gamma changes sign, from long to short or back. Researchers track flips to understand intraday acceleration and mean reversion.
With point-in-time GEX you can map walls and flips historically without survivorship bias. The SPX gamma series is the foundation for studying index dealer positioning across market cycles.
Coverage
FinzData gamma exposure coverage is broad and historical. SPX, NDX, RUT, VIX, XSP, DJX and 11,209 tickers including single stocks and ETFs are available since January 2010.
All series are point-in-time at 17:00 New York, suitable for next-day research and backtests. The Python client mirrors yfinance, so you can pull GEX with the same workflow you use for prices.
For comparison, Databento Core Indices history starts from 7 December 2025 as of October 2026, https://databento.com/pricing. FinzData fills the gap for long-term gamma research.
CODE: Pull SPX GEX and analyse next-day volatility by sign
import finzdata as yf
# SPX gamma exposure history
gex = yf.gex("SPX", start="2010-01-01")
print(gex.tail())
# Example: conditional next-day volatility by sign of net GEX
# gex is a DataFrame with a net GEX column; sign determines regime
short_days = gex[gex['net_gex_bn'] < 0]
long_days = gex[gex['net_gex_bn'] > 0]
print("Short gamma sessions:", len(short_days))
print("Long gamma sessions:", len(long_days))Pricing for GEX add-on
Gamma exposure is available as an add-on to owned market data. Pricing is one-time and you keep the data.
- GEX $295 on its own
- $195 as an add-on to a look-back bundle
No metered usage fees. Once purchased you can run reproducible research offline and share CSVs with collaborators.
Compare with usage pricing models. As of October 2026 Databento offers $125 per team free credits expiring after 6 months, https://databento.com/pricing. Owning GEX removes dependency on expiring credits.
Start free
Start researching SPX gamma exposure with a free API key. The free tier gives last 12 months of every dataset, 1,000 API calls per day, no card required.
Get a free API key at https://api.finzdata.com/ and explore samples and pricing.
Frequently asked questions
What is SPX gamma exposure?
SPX gamma exposure is the net gamma held by dealers across S&P 500 options. Net short gamma means dealers hedge by buying dips and selling rallies, which can amplify moves.
Does short gamma predict direction?
No. Short gamma predicted size, not direction in the FinzData study. Past behaviour is not a forecast.
How far back does FinzData SPX GEX go?
Point-in-time SPX gamma exposure is available from January 2010 to October 2026 with 17:00 New York values.
How does this compare to Databento?
As of October 2026 Databento Core Indices history starts from 7 December 2025. See https://databento.com/pricing. FinzData provides longer history for gamma research.
Can I use the yfinance client?
Yes. Install finzdata and use import finzdata as yf. yf.gex('SPX', start='2010-01-01') returns a pandas DataFrame.