The date the option's life ends. After it, the option is worthless if not exercised.
What it determines
The Expiration Date is the last day a contract lives. After it, the contract turns into its spot value if it has one, or dies worthless. Every property of the contract is measured against it, and all time value is the price of the days left until this date.
The expiration changes the contract's character
Short-dated options (days to weeks) are cheap and sharp: high Gamma and fierce Theta. They suit fast moves and die fast. Long-dated ones (months to a year or more · LEAPS) are calmer: less sensitive to time, more sensitive to implied volatility, and they cost more. Choosing the expiration weighs as much as choosing the strike price.
Expirations that became a grid
Expiration is no longer a single monthly event: indexes and major symbols now expire daily, and most stocks weekly. So liquidity and positioning spread across expirations, and reading one chain without looking at its neighbors is an incomplete read.
Third-week expiration
The third Friday of the month is still the heaviest standard expiration. Old monthly contracts expire and the largest blocks of open interest sit around it, so price pinning near big strikes (Pinning) gets stronger and positioning is rebuilt afterward. The OpEx calendar in the platform's tools measures this.
Common mistake
Matching the contract's term to the trade idea with no margin: someone who expects a move within two weeks and buys a contract expiring in exactly two weeks is betting on the full timing. A slightly longer term costs more in exchange for room if the timing is off.
Where to see it on the platform
The options chain shows the available expirations, the options calculator works out the effect of the days left, and the time decay curve draws it day by day.
