XBI Gamma Exposure (GEX)
SPDR S&P Biotech ETF · computed from open interest and end-of-day quotes as of 2026-07-10 · spot $159.03 · updated nightly
Net GEX by strike
■ positive (dealers dampen moves) ■ negative (dealers amplify moves) — strikes within ±15% of spot.
Gamma walls
| Strike | Net GEX / 1% | Share of total gamma | Distance from spot |
|---|---|---|---|
| $155 | −$16M | 13.6% | -2.53% |
| $168 | $6M | 5.3% | 5.64% |
| $164 | $5M | 4.1% | 3.13% |
| $170 | $5M | 4.0% | 6.90% |
| $149 | −$4M | 3.7% | -6.31% |
GEX by expiration
| Expiration | Net GEX / 1% | Absolute GEX |
|---|---|---|
| 2026-07-17 | $9M | $50M |
| 2026-07-24 | −$5M | $6M |
| 2026-07-31 | −$10M | $17M |
| 2026-08-07 | −$234,184 | $1M |
| 2026-08-14 | $275,193 | $317,243 |
| 2026-08-21 | −$1M | $41M |
What is gamma exposure?
When you buy an option, a market maker usually takes the other side and hedges by holding shares of XBI. As the price moves, the amount they must hold changes — that sensitivity is gamma. GEX aggregates it across all open contracts (calls positive, puts negative, per the standard dealer-positioning convention) into a dollar figure per 1% move.
In a positive gamma regime, dealers sell into rallies and buy dips — mechanically dampening volatility. In negative gamma, hedging flows push in the same direction as the market, amplifying moves. The gamma flip ($162.05 right now) is the estimated price where the regime switches, and large single-strike concentrations ("gamma walls") often act like short-term magnets or barriers. These are estimates built on simplified assumptions — positioning context, not predictions. Full explainer: what is GEX?
More XBI options data
See the XBI max pain dashboard for the expiry-pinning view of the same open interest , or check which ETFs overlap with XBI if you hold it as a fund.
GEX for other tickers
GEX is computed nightly from end-of-day open interest and quotes using a Black-Scholes approximation (r=0, q=0), matching common retail GEX conventions (methodology). Derived metrics only — not raw market data, not investment advice.