Weekly options are listed to provide expiration opportunity every single week. Weeklies are typically listed on Thursdays and expire on Fridays, provided that such expirations were not previously listed (i.e. weeklies are not listed if they would expire on a 3rd Friday when the monthlies do or if a quarterly option would expire on the same day). Weekly options can provide opportunities for traders to implement more targeted buying, selling, or spreading strategies. We will mainly use them in our system for earnings trades for their shorter duration.