What happens at expiration to my short option?

You should review your positions prior to expiration to determine whether you have adequate equity in your account to exercise your options. You should also determine whether you have adequate equity in the account if an in-the-money short option position is assigned to your account. You should also be aware that short options positions may be exercised against you by the long holder even if the option is out-of-the-money…

Spread positions can have unique expiration risks associated with them. In the case of U.S. securities options, the OCC will automatically exercise option contracts at expiration only if the option is In-the-Money by $0.01 or greater. If both legs of your expiring option spread are In-the-Money, then the long leg will be auto exercised by the OCC and the short may be assigned. It is possible that a short expiring option leg that finishes In-the-Money is lapsed by the owner and you will not be assigned. For non-U.S. options, please refer to the…

While it is unlikely that holders of in-the-money long options will elect to let the option lapse without exercising them, certain holders may do so due to transaction costs or risk considerations. In conjunction with its expiration processing, OCC will assign option exercises to short position holders via a random lottery process which, in turn, is applied by brokers to their customer accounts. It is possible through these random processes that short positions in your account be part of those which were not assigned…

The only action one can take to prevent being assigned on a short option position is to buy back in the option prior to the close of trade on its last trading day (for equity options this is usually the Friday preceding the expiration date although there may also be weekly expiring options for certain classes). When you sell an option, you provided the purchaser with the right to exercise which they generally will do if the option is in-the-money at expiration…