Let's say you buy some stock and sell some covered calls against it. You are using a brokerage that does not allow you to sell calls unless they are covered. Tomorrow, at 4pm, the calls you sold are worthless. Are they officially worthless as of 4pm, or not until over the weekend when the options contracts are settled? Will the brokerage allow you to sell your stock in the aftermarket after 4pm on Friday, or will it not because according to their system the options you sold are not officially worthless yet, and thus according to their system/software you cannot sell any stock when you have sold calls against it? I do not want to have to hold the stock over the weekend, I would like to sell it in the aftermarket on Friday. If I did have to buy back the calls before I sell the stock, I could try to buy them at say 3:50pm. But if they are about to expire worthless, what kind of liquidity will there be on the calls? Will I have to pay some outrageous ask price to buy back the calls?