GEXfocusDelta: directional exposure
Delta measures how much an option's value changes when the underlying moves. For a dealer, it also represents how much directional exposure needs to be hedged.
That is why Delta connects options positioning to real trades in spot or futures.
In a structural read, Delta is not only used to value an option. It helps estimate how much underlying may be needed for dealers to remain neutral as aggregate exposure changes.
Gamma: how fast Delta changes
Gamma measures how much Delta changes as price moves. If Gamma is high, a hedge that was balanced moments ago may need to be adjusted quickly.
This is why Gamma sits at the center of options structure. The market responds not only to current exposure, but to how fast that exposure can change.
A high-gamma session can feel different because each small move changes hedge needs. The result can be containment if hedging absorbs the move, or acceleration if hedging follows it.
Why ATM options are sensitive
Options near the current price usually carry high Gamma. When spot moves around those strikes, Delta can change quickly and force more frequent hedge adjustments.
On very short-dated expirations, especially 0DTE, this effect can become much stronger.
That is why it is not enough to know where Open Interest is large. You also need to know whether that OI is close to price and sensitive enough for hedging to become active.
How to use it in a daily read
- Locate relevant Open Interest.
- Check whether it is close to spot and expiration.
- Interpret whether Gamma can create containment, acceleration or transition.
- Validate the structure during the session.
Delta explains how much hedge is needed. Gamma explains how much that hedge can change when price moves.