How to Read the Greeks Bars:
Green, Red & Magnitude
- The Greeks page has two kinds of tabs. Directional tabs — GEX, DEX, Vanna, Charm — color by sign: green = positive, red = negative. Magnitude tabs — VEX, Theta, OI — color by size only, with no buy/sell direction to read.
- VEX never has a red bar. Vega is positive for both calls and puts, so VEX only measures how big the vol risk is at a strike — not which way dealers hedge. A tall VEX bar is a "vol-bomb" zone, not a sell signal.
- The trap: on directional tabs, color is the sign of the exposure — not the trade the dealer makes. The hedge is a second step and it can flip. So "longest red bar = dealers sell" is not a rule that holds across the page.
- The longest bar on any tab marks where that Greek concentrates — on GEX that's your Call Wall / Put Wall; on VEX it's the strike most exposed to an IV gap.
Two Kinds of Bars
Every tab on the Greeks page draws one horizontal bar per strike. But the bars don't all mean the same thing, and that's the source of most of the confusion. There are exactly two families:
| Family | Tabs | What color means |
|---|---|---|
| Directional | GEX · DEX · Vanna · Charm | Green = positive exposure, red = negative exposure. The sign carries information about dealer positioning. |
| Magnitude | VEX · Theta · OI | A single tone scaled by size. No positive/negative split, because the quantity doesn't change sign in a way that maps to "buy vs sell." |
Get this distinction right and the whole page reads cleanly. The rest of this guide walks each tab.
Directional Tabs: Green = Positive, Red = Negative
On these four tabs, the color tells you the sign of the exposure at that strike. Bar length is proportional to the magnitude relative to the largest bar on the chart.
| Tab | What the sign means | What the longest bar marks |
|---|---|---|
| GEX | Call gamma plots to the right, put gamma to the left. Bar length scales with the absolute value. | The Call Wall (largest call-side bar) and Put Wall (largest put-side bar). |
| DEX | Positive = dealer net long delta at that strike. Negative = dealer net short delta. | Where dealer delta concentrates most heavily on each side. |
| Vanna | The sign tells you which way dealer delta shifts when implied volatility moves. The strike where it flips sign near spot is the Vanna Trigger. | Where a change in IV moves dealer hedging demand the most. |
| Charm | The sign tells you which way dealer delta drifts as time passes (delta decay per day). | Where the passage of time pushes dealer hedging demand the most — sharpest into expiry. |
Magnitude Tabs: Size, Not Direction
These three tabs answer "how much," not "which way." They use a single tone scaled by size.
| Tab | What the bar measures | Why there's no green/red split |
|---|---|---|
| VEX | Dollar P/L sensitivity to a 1-point move in implied volatility at that strike. | Vega is positive for both calls and puts, so VEX never goes negative. The longest bar is the strike most exposed if IV gaps — a "vol-bomb" zone. |
| Theta | Dollar-per-day time decay at that strike. | It's effectively one-signed — the long-option side bleeds value over time. The bar shows where that decay concentrates. |
| OI | Raw open interest: call OI to the right, put OI to the left. | It's a contract count, not an exposure. No Greek, no sign — just how many contracts sit at each strike. |
Color Is the Sign, Not the Trade
Here is the single most important point, and the one that trips up careful readers. On the directional tabs, the color encodes the sign of the exposure — it does not directly tell you whether dealers are buying or selling the underlying. The hedge dealers put on is a second step, and it can be the opposite of what the color seems to suggest.
Take DEX as the worked example:
That's why "longest red bar = dealers sell" isn't a rule that holds across the page. It depends entirely on which Greek you're looking at, and on the difference between the sign of the exposure and the direction of the hedge. Read the color as "positive or negative exposure," then reason one step further to the hedge if you need the trade direction.
Using the Longest Bar
Across every tab, the longest bar is telling you where that particular Greek concentrates. What that means in practice depends on the tab:
- GEX — the tallest bars are your structural levels: the Call Wall above spot, the Put Wall below it. These are where dealer hedging is densest — price tends to pin or stall there in a long-gamma regime (above the flip), and to accelerate through them in short gamma (below the flip).
- DEX — the tallest bars mark where dealer delta is most lopsided, and therefore where a spot move forces the most hedging.
- Vanna / Charm — the tallest bars flag where an IV change (Vanna) or the simple passage of time (Charm) will push the most hedging demand. These matter most around events and into expiration.
- VEX — the tallest bar is the strike most exposed to a volatility gap. Useful before earnings, CPI, FOMC — anywhere IV can jump.
- Theta — the tallest bar shows where time decay is heaviest: pain for option buyers, income for sellers.
One last note on DTE: every Greek behaves differently by expiration — gamma dominates 0DTE, vanna peaks at 30–60 days, vega dominates LEAPs. The Greeks page is bucketed by DTE for exactly this reason, so always read the bars within the DTE view you've selected. For the math behind each Greek and our sign conventions, see the deep dive below.