Not so long ago on TWS, I remember FDAX was switched at 6:15 Pm GMT+1 (or maybe it was 5:45 but it was for sure one of those 2 and 'special'. You could not use intraday margins close to 10 PM) ...which does not match the rulethumb that they display and that you quote. That's why I'm requesting practical experience.
As I am not going to the time limits in the FDAX and never trading overnight I can only give my observation of the SIM
FDAX which is parallel to the real: there the calls for margin change always came at 09:35pm and were in function at 09:45pm - 15 minutes before official futures closing.
..best to ask this question to the IB support (mail or phone) - to get the actual margin change times
They usually drop to intraday requirements during the outcry hours or simply the regular trading hours in general for most contracts.
As mentioned before, IB will send you a warning 10min before switching to overnight margin requirements (only if you do not meet that requirement) and it is also worth remembering that they switch to overnight requirements 15min before the official regular close.
I do not trade all the contracts you mention below, but for YM that I do trade from time to time, I know that the intraday margin requirement starts at 15:30 CET and ends at 22:00 CET while the official close is at 22:15 CET.
The warning will be sent to you by email, and it will pop up on TWS as well at 21:50 CET and it gives you 10min to react, or they will start closing out your position between 22:00 CET and 22:15 CET at their own convenience and until you can meet the overnight requirements.
Successful people will do what unsuccessful people won't or can't do!
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