The best single chart for dealer positioning is gamma exposure plotted per strike: one bar at each strike price, height equal to the aggregate dealer gamma at that strike, signed. Once you can read it, a lot of intraday price action stops looking random. The chart answers three questions at a glance - where does price get stuck, where does it accelerate, and which level marks the boundary between the two.
What Each Bar Represents
A single bar at strike K shows the total gamma exposure of dealers (market makers) in options struck at K, summed across all active expirations. The sign matters as much as the size:
- Positive bar (long dealer gamma). Dealers hold net long gamma at this strike. When price moves toward K, they hedge against the move - selling into rallies, buying dips. This dampens volatility.
- Negative bar (short dealer gamma). Dealers are net short gamma at K. When price moves, they chase - buying as it rises, selling as it falls. This amplifies volatility.
The height tells you how much hedging pressure concentrates there. A bar twice as tall creates roughly twice the hedging flow for a given move.
Key Insight
The sign of the bar isn't an opinion, a forecast, or a signal - it's a mechanical consequence of who wrote which options. Positive-GEX strikes mean customers are net short calls / long puts (dealers took the opposite side, so dealers are long gamma). Negative-GEX strikes mean customers are net long calls / short puts.
The Four Levels Every Reader Should Extract
A GEX-by-strike chart typically gets reduced to four derived levels. These are what you actually trade around:
1. Call Wall
The strike with the single largest call-side gamma exposure. Because dealers sell into rallies toward this strike, the call wall tends to act as intraday resistance. Breakouts above the call wall often require either (a) a regime change where dealers flip short gamma or (b) enough buy pressure to absorb the dealer selling.
2. Put Wall
The strike with the single largest put-side gamma exposure - the mirror of the call wall. Dealers buying dips at the put wall provides mechanical support. Breakdowns below the put wall often signal a shift into a negative-gamma regime.
3. Gamma Flip
The price at which the cumulative GEX (summing strikes from low to high) crosses zero. Above the flip, dealers are net long gamma across the book - volatility is suppressed, mean-reversion dominates. Below it, dealers are net short - volatility expands, trends persist longer. The gamma flip is the single most-watched GEX-derived level.
4. Zero-Gamma Strikes
Strikes with bars close to zero, especially between the walls. These are "transparent" strikes where price can move freely without significant dealer interference. Useful for identifying clean breakout zones.
Common Chart Shapes and What They Mean
GEX profiles fall into a few recognizable shapes. Knowing which one you're looking at tells you what kind of day to expect:
- Tall positive center, flat wings. Heavy long-gamma concentration near spot. Classic pin-to-max-gamma day - expect range-bound price action and compressed realized vol.
- Tall call wall above spot, smaller put support below. Bullish drift likely hits resistance at the call wall. Breakouts require real buying volume.
- Flat or negative bars across the chart. Short-gamma regime. Moves extend, gaps don't fill, trend-following works. Usually correlates with spot being below the gamma flip.
- Barbell - big positive far above and below, hollow middle. Heavy expiration concentration at distant strikes. Near-term action likely decoupled from the walls; watch the closer strikes instead.
Reading GEX by Strike in Practice
A five-second read of any GEX-by-strike chart:
- Find the gamma flip line. Is current price above or below it? That sets the regime.
- Locate the call wall. If above current price, that's your resistance target. If already broken, the next wall up becomes the new resistance.
- Locate the put wall. Same logic, downside.
- Scan for outliers. Any unusually tall single bar near spot? That strike will act as a magnet intraday.
That's the whole workflow. Everything else - DEX, VEX, CHEX, skew, term structure - adds context, but the per-strike gamma chart alone gets you most of the way to "what levels matter today."
Where to See GEX by Strike Live
Free, no signup: the FlashAlpha GEX tool renders per-strike gamma for any US-listed ticker. The annotated levels (call wall, put wall, gamma flip) are drawn on top of the bar chart so you don't have to extract them manually.
For common requests:
For programmatic access, the /v1/exposure/gex/{symbol} endpoint returns the per-strike array plus net GEX and the gamma flip. The /v1/exposure/levels/{symbol} endpoint returns the derived walls in one call:
curl -H "X-Api-Key: YOUR_KEY" \
"https://lab.flashalpha.com/v1/exposure/gex/SPY?expiration=2026-05-16"
GEX response includes strikes[] (per-strike call/put/net gamma + OI + volume), net_gex, gamma_flip, and net_gex_label (positive/negative regime). The levels endpoint returns call_wall, put_wall, and gamma_flip on the levels object. See GEX reference → and Levels reference →
What GEX by Strike Can't Tell You
One honest limitation: per-strike gamma is a snapshot of the option side of dealer positioning. It doesn't account for:
- Dealer long-vol hedges in other products - VIX futures, variance swaps, etc. A dealer short gamma in SPY might be hedged via VIX and behave differently than the chart suggests.
- Customer-side flows that close rather than open - GEX captures stock, not intention.
- Vanna and charm drift - as IV and time change, dealer deltas shift even without price moving. For those, vanna and charm exposure cover what GEX alone misses.
Per-strike GEX is the highest-leverage single chart in options analytics. It's not the whole picture.
