SPX 0DTE Gamma Exposure (GEX), Vanna & Charm Hedging Ratios, and OCC STANS Intraday Margin Framework
SPX 0DTE options account for 59% of S&P 500 options volume (Source: Cboe Global Markets, 2025-10-10), driving dealer GEX, Vanna, Charm, and OCC 20-minute STANS margining.
