Each series of options (a series is a set of contracts that all have the same underlying stock) belongs to a particular expiration cycle.  There are three fixed expiration cycles throughout the year which results in contracts having a standard three month duration:

• January, April, July, and October (JAJO)
• February, May, August, and November (FMAN)
• March, June, September, and December (MJSD)

In addition to these fixed expiration cycles, options contracts with shorter contract periods of just one or two months may also be available within cycles.

An option contract always expires on the third Saturday of its expiration month.  That means the last day to exercise or otherwise trade in an option is the third Friday of the expiration month (technically it’s the last trading day before the third Saturday but, unless the market is closed for a holiday, that will be on a Friday).

But, it’s probably not a good idea to wait until the last minute before market close on Friday to make your trade as there’s the potential that it won’t get executed in time.  You don’t get a grace period so make sure you leave plenty of trading time in which your trade can be executed.  Make sure to check with your brokerage as well because it may specify an earlier cut-off time for trades involving expiring options to ensure they’ll be able to process the trade before market close.

That last trading day before option expiration is also the last day in which an option contract you sold can be executed forcing you to buy or sell shares in the underlying stock.  You’ll typically be notified of an exercised contract by being delivered instructions to transfer funds in the event a call option you sold has been exercised or to authorize the payment for 100 shares of the underlying stock in the case of an exercised put option contract.