https://zh.toptenid.com/post/when-the-settlement-operation-is-carried-out-after-the-end-of-the-general-trading-session-such-as-the-market-situation-changes-during-the-after-hours-trading-session-or-the-futures-traders-write-off-part-or-all-of-their-positions-during-the-after-hours-trading-session-and-other-factors-the-amount-of-equity-is-not-less-than-the-maintenance-margin-required-for-the-unoffset-positions