Learn in order
Options & hedging basics
You do not need to calculate the Greeks first, but you do need to understand why dealers may adjust their hedges as price, time, and volatility change.
What options are
| Term | Intuitive explanation | Why it appears on the page |
|---|---|---|
| Call | The right to buy the underlying at an agreed price in the future | Bullish positioning and hedging demand can concentrate at different Call strikes |
| Put | The right to sell the underlying at an agreed price in the future | Bearish and protective positioning can concentrate at different Put strikes |
| Strike | The price specified by the options contract | The price coordinate for each row of the position heatmap |
| Expiry | The date on which the contract expires | Structures at different expiries may exert different influence |
| Premium | The price paid to purchase an option | Often used in order flow to measure the size of a trade |
| OI | The stock of contracts that remain open | Helps explain position size, but does not reveal real-time direction or whether a trade opened a new position |
Who does what in the market
Options activity includes buyers, sellers, institutions, dealers, hedges, and multi-leg strategies at the same time. SmartTrace focuses on the portion that may create mechanical hedging demand, but it cannot directly observe every participant's true intent.
Dealers
A dealer's typical role is to provide quotes and liquidity while minimizing directional risk. After taking the other side of options orders, dealers may trade the underlying, ETFs, or futures to adjust their Delta hedge. “May” matters: their actual hedging instrument, timing, and size are not fully observable.
Institutions, hedgers & retail traders
An institutional options order may express a directional view, but it may also be protection, a roll, a spread, or a volatility trade. Retail orders are smaller individually, but concentrated same-direction activity over a short period can still change the risk dealers must manage. Do not translate any single order into “someone is definitely bullish/bearish.”
Delta: current directional exposure
Delta describes approximately how an option's price changes when the underlying moves. It can also be understood as the contract's current directional Exposure in “share-equivalent” terms. Call Delta is usually positive; Put Delta is usually negative.
If dealers acquire directional Exposure by taking the other side of orders, they may use the underlying or related instruments to offset some of that risk. When price changes, the option's Delta may change too, so the original hedge no longer matches perfectly.
Gamma: why hedging changes price behavior
Gamma measures Delta's sensitivity to price changes. Gamma is often more pronounced in contracts near spot and near expiry, so dealer rebalancing demand may become more concentrated there.
| Environment | Typical rebalance when price rises | Typical rebalance when price falls | Common market characteristics |
|---|---|---|---|
| Positive Gamma | Tends to sell to reduce Exposure | Tends to buy to reduce Exposure | Suppressed volatility, mean reversion, range-bound tug-of-war |
| Negative Gamma | Tends to buy to reduce Exposure | Tends to sell to reduce Exposure | Amplified volatility, acceleration, wicks, and overshoots |
This table describes the classic hedging intuition, not a formula for forecasting direction. On its own, it also cannot establish that a level must become support, resistance, or a target.
GEX: viewing Gamma as a map
GEX is a structural view that aggregates Gamma Exposure across strikes and expiries. Its purpose is to help you locate areas where potential hedging effects deserve more study, not to forecast price for you.
- Large absolute-value nodes: areas to prioritize, not levels price must reach or reverse from.
- Position above or below spot: helps map potential floors, ceilings, and checkpoints along the path.
- Air pockets between nodes: helps identify areas where price may encounter less friction in transit.
- Changes in nodes: more important than a static snapshot; growth, decay, and migration can all alter the structure.
Time & volatility: Theta, Vega, Vanna
| Concept | What it describes | How to interpret it in practice |
|---|---|---|
| Theta | The decay in an option's value as time passes | Options prices and position structures can change faster near expiry; short-dated directional trades require more attention to time cost |
| Vega | An option price's sensitivity to implied volatility | Changes in implied volatility affect option value and risk Exposure, especially around earnings and macro events |
| Vanna | Delta's sensitivity to changes in implied volatility | When spot and volatility change together, dealer hedging pressure may change; multi-day moves cannot be understood from Gamma alone |
| Charm | Delta's sensitivity to the passage of time | Even if price barely moves, hedging demand may change near the close or expiry |
GEX for today, VEX for multiple days
Gamma hedging demand is driven by price: as soon as spot moves, dealers need to adjust positions, so GEX primarily explains Today—whether the session is likely to be a sticky range or an acceleration-prone trend. Vanna hedging demand is driven by volatility: even if spot barely moves, a change in implied volatility—such as a volatility crush or surge after earnings or economic data—can force dealers to rebalance. That adjustment often takes more than one pass and can persist for several days. This is one reason a clear-looking GEX chart may not align with price: today's structure may be unchanged while Vanna has quietly rewritten the direction of the multi-day drift.
- Around earnings, FOMC, CPI, and other events that can move implied volatility sharply, check VEX as well as GEX.
- Charm follows similar logic, but time rather than volatility is the driver. As the close or expiry approaches, the Delta of open contracts decays systematically and dealers may need to adjust positions. This helps explain why price can become pinned—or suddenly receive a directional push—near the close or during monthly expiry week.
- Suggested order: use GEX first to assess Today's structure. If a volatility event is nearby, or price clearly disagrees with the GEX structure, check whether VEX is producing a multi-day drift. Near the close or expiry, use Charm as a reminder not to mistake current stillness for an absence of hedging pressure.
Understand the model's limits
- Public data and models cannot fully identify the true direction of every order, whether it opens or closes a position, or how dealers actually hedge it.
- News, liquidity, concentrated expiries, cross-market trading, and changes in implied volatility can quickly invalidate an established structure.
- Position data can only raise or lower confidence in a price thesis. It cannot replace price action, stops, or position management.
What to read next
After understanding these foundations, continue to “Start from the chart: six-step process,” then read “Nodes, floors & air pockets.” This sequence teaches you what to ask before showing you how to interpret the heatmap's information.