Option Greeks describe how a model estimates premium sensitivity to changes in the underlying, time and volatility. They help organise risk, but they change with market conditions and do not predict the future premium with certainty.
Gamma explains changing delta
Gamma estimates the change in delta for a move in the underlying. High gamma can make near-expiry at-the-money options respond quickly, which increases both opportunity and position-management difficulty.
- Underlying level
- Moneyness
- Time remaining
- Position quantity
Theta and vega add a second decision clock
Theta describes modelled time decay, while vega describes sensitivity to implied volatility. A directional view can be broadly right yet produce a poor option outcome if time decay or volatility contraction dominates.
Translate sensitivities into scenario risk
Greeks are estimates, not stop levels. Combine them with liquidity, spread, underlying invalidation and maximum rupee loss before deciding strike, expiry and quantity.
Run a small scenario grid before choosing the contract
Record the current premium and Greeks, then compare several underlying moves, time intervals and volatility changes. The goal is not an exact forecast; it is to identify which input can dominate the position and where the thesis is most fragile.
Repeat the exercise for two nearby strikes or expiries. A contract with a lower premium may carry greater time sensitivity, weaker liquidity or a different response to the underlying.
- Underlying up and down
- One session of time
- Volatility expansion and contraction
- Alternative strike or expiry
Review realised sensitivity after the position
Compare the actual premium change with the underlying, time and implied-volatility movement. Differences from a simple delta estimate do not necessarily mean the model failed; several inputs changed together.
Use review to improve contract selection rather than to retrofit a prediction. Greeks are most valuable when they reveal exposure before entry and explain risk after the event.
- Entry Greeks
- Underlying movement
- Volatility change
- Spread and realised exit