Article

SPX, NDX, SPY, QQQ: Same GEX Map, Different Tape

Four underlyings, one GEX engine — why SPX looks smooth, NDX jumps farther, and QQQ/SPY can disagree with their index cousins during the same RTH window.

By GammaTape6 min read

Quantitative formulas — four chains, one gamma-exposure methodology

GammaTape runs the same 0DTE GEX pipeline on SPX, NDX, SPY and QQQ. The levels mean the same thing on each tab — call wall, put wall, zero gamma, expected move — but the tape that feeds them does not. Knowing the differences keeps you from treating every chart as a clone of SPX.

Index vs ETF chain

  • SPX / NDX — cash-settled index options; strike steps are wider (often 5 pts); GEX levels map to ES / NQ.
  • SPY / QQQ — equity ETF options; 1-pt grids, different liquidity pockets, and their own 0DTE calendars.
  • Basis & timing — ETF prints can stutter or print oddly around auctions while the index path looks continuous.

That is why a QQQ path can look “blocky” for a stretch while SPX on the same afternoon is clean: thinner ETF prints and parity oddities hit the minute bars harder before filters settle them. Prefer SPX/NDX when you trade ES/NQ levels; use SPY/QQQ when you care about the ETF book itself.

Session replay across instrumentsGammaTape
Replay trains the eye on how each instrument’s walls and path behave — not just one screenshot.

How to use the four tabs

  1. ES traders: start on SPX; glance at SPY only for ETF-specific flow.
  2. NQ traders: start on NDX; expect zero gamma and walls to move in larger point chunks than SPX.
  3. Compare OI vs Volume on the instrument you actually hedge — disagreement on QQQ does not automatically copy to NDX.
  4. When one tab looks weird, check the others before assuming the engine failed.

Switch instruments on one dashboard — same engine, four chains.

See plans

Related

Keep reading