Angie · learn
Gamma and theta
Gamma is how fast delta changes; theta is how much value the option loses per day. Together they are why an option buyer is racing a clock.
Updated 2026-09-05
Gamma and theta are the two forces acting on an option holder, and they pull in opposite directions.
- Gamma is how fast delta changes as the underlying moves. High gamma means the position's exposure accelerates in your favour when you are right, and against you when you are not. It is highest at the money and near expiry.
- Theta is how much value the option loses per day purely from time passing. It is the cost of holding, it accelerates as expiry approaches, and it is what the option seller is collecting.
An option buyer is long gamma and short theta: paid for movement, charged for waiting. A seller is the reverse. That trade-off is the whole economics of the instrument, and it is why an option can lose money on a week when the underlying moved exactly as predicted, only slowly.
Both effects intensify sharply in the final weeks. A near-dated at-the-money option is the highest-gamma, highest-theta thing you can hold, which is why short-dated options behave less like investments and more like a stopwatch.
See also
- Delta — How much an option's price moves for a one-dollar move in the underlying. It doubles as a rough probability of finishing in the money.
- Intrinsic and time value — Intrinsic value is what the option would be worth exercised right now. Everything else in the price is time value, and it decays to zero at expiry.
- Option premium — What the buyer pays the seller for the contract. It is the option's price, and it is made of exactly two things: intrinsic value and time value.
Educational content, not investment advice. Angie explains how a valuation is built so you can judge it yourself. What you do with that is your call.
