I'm trying to better understand the trading hours of the E-mini 500 S&P, which according to the CME Groups web pages are shown like this: enter image description here

This is, however, rather incomprehensible for anyone non-expert.

There (and elsewhere) they say there is a "Daily Maintenance" hour between 4pm - 5pm (Mon-Thu).

Q: What does that mean, and what going on at that time (what significance does it have)?

  • Did you "Contact Us" and ask them?
    – RonJohn
    Jun 12, 2021 at 23:43
  • According to the contract specifications, the maintenance period is 5pm - 6pm (Monday - Thursday), and is only applicable to Trade at Cash Open (TACO) trading.
    – Flux
    Jun 13, 2021 at 3:44
  • Incredible the amount of Jargon on the CME web pages. (They should be banned from having any webpages at all.) What the heck is a TACO or BTIC? Still no clarity as to what exactly they are doing at that time. However, they have just recently cancelled the 15 min trading pause at 3:15-3:30 pm (CST).
    – not2qubit
    Jul 1, 2021 at 21:50
  • Some additional info on the Settlement procedures, but I don't really understand it.
    – not2qubit
    Jul 1, 2021 at 21:55

1 Answer 1


The exchange is reserving that time to make changes, maintenance or review processes. For example they might use that time to make data backups or software upgrades without risking in process trading.

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