From the CME Globex Control Center, here is the summary of KEY changes, per CME market segment
Thursday, December 23, 2021 - Normal Market Close Time. However, since the markets will remain closed until Sunday - we will require *Any open positions must meet Exchange Maintenance Margin 15 minutes before the market close (3:45 pm CST).
https://www.ampfutures.com/trading-info/margins/
View Full List: https://www.ampfutures.com/trading-info/holiday-hours/
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