回复@holiczsy: “For customers with long option positions, this means that your positions will be auto-exercised based on the settlement price determined by OCC at 4:00 pm (16:00) but you may choose to override this automatic exercise by submitting a request to IBKR until 5:29 pm (17:29 EST). ” - 这句话很关键。IB是允许你在期权到期当日的4点收盘后（5：29分前），通过直接通知它们来改变（即“override”）自动行权的。这点非常好！我的平台基本上做不到这点，虽然我很久以前就和他们交涉过。不但做不到，基本上在最晚3：15-25分左右，我作为客户就得对价内的calls是否行权做出决定（如果我不想自动行权的话）了。当然在我的平台上，这个早就是这样，不是最近针对GME的。
The default automatic exercises and assignments processing is determined by the Option Clearing Corporation (OCC) based on the settlement price determined by the as of 16:00 pm Eastern Time. However, the OCC permits client manual exercise decisions for exercises until 5:30 EST (17:30). As the underlying stocks continue trading in the “evening” trading session from 4:00 pm(16:00) through the exercise cutoff, these stocks can move significantly after the close of regular which can impact exercise decisions.
Customers with Long Option Positions For customers with long option positions, this means that your positions will be auto-exercised based on the settlement price determined by OCC at 4:00 pm (16:00) but you may choose to override this automatic exercise by submitting a request to IBKR until 5:29 pm (17:29 EST). Clients should always monitor the markets during this window and determine whether they wish to exercise their long option positions. This is especially important given the extreme market volatility these securities have experienced. We therefore urge each of you to monitor your positions between the close of option trading and the exercise notice cutoff to determine your exercise decisions if different than the automatic OCC criteria.
Please click here for information on how to override the automatic exercise criteria after 4:00 pm (16:00). IBKR cannot accept requests to exercise an option by ticket or phone so please submit your request through TWS or Client Portal.
Customers with Short Option Positions If you are short the options, you may be assigned until 5:30 pm based on the decisions to exercise by other market participants. These traders will have the ability to see the current market price after the close of options trading, at a time when you will not be able to close your option position.
Again, these stocks may move significantly the after the close of regular trading at 4pm. This may mean that a position that was well out of the money at 4 pm may be in the money, perhaps significantly, by the time it is exercised against you. Thwre is no way to predict whether the long holder of the option will exercise based on the 4:00 pm(16:00 price) or some later price up to 5:30 pm (17:30). The only way to avoid this volatility is to close out your short option position before 4 pm. To repeat, the only way to mitigate the uncertainty of your post-expiration stock position is to close out short positions prior to the end of the trading session.