SPX GEX Today
S&P 500 gamma explained
S&P 500 ETF Options, Understanding Dealer Positioning
Interactive heatmap available in TeploMap
SPY (ETF) and SPX (index) both track the S&P 500 but have different option characteristics:
SPY: higher retail activity, more frequent strikes, American-style exercise.
SPX: institutionally dominated, larger notional, European-style, cash-settled.
Both contribute to S&P 500 hedging flow. Watching both gives a more complete picture of dealer positioning.
Levels shift intraday. Dealer positioning recomputes as new options trade and existing positions roll off, so the gamma flip and walls can drift through the session.
Expiration matters. Near-term options carry the largest gamma exposure. Multi-expiration views show how near-term concentration compares to the longer-dated structure.
Context, not prediction. These levels describe observed dealer positioning. They do not forecast price and should be read alongside spot, realized volatility, and macro context.