I could imagine that a change in "residency" could happen darn near overnight, should the Chicago socialists push too far too fast. I wager these socialists are not really and fully up to the "Chicago way" if it became a clear matter of "redistribution" in the Marxist manner.
California and New York are finding their reliance on super-rich paying through the nose is motivating said taxpayers to change residence at a pace startling to many who always thought the game could be played "forever."
CME residency changing is becoming a matter of "click."
The NYSE and NASDAQ are the same way, the NYSE trades are primarily happening across the river in NJ, not on Wall Street.
All of these electronic exchanges have complete disaster recovery sites in remote locations and could switch operations in a matter of a couple of hours.
Back in 2008 or 2009 I was contracted to Bank of America on a team to reengineer the voice network nationwide to a Cisco Systems Voice System.
One of the sites I was assigned was in Columbia, SC located near Charlotte, NC where the HQ of Bank of America is located.
The site in Columbia was a Disaster Recovery site, with about 200 full time workers in a multistory nondescript building that could easily provide space for 1200 to 1500 people, we installed around 1500 phones for BofA, all the phones were setup with voice mail in the event the HQ office was taken offline for any reason, the employees could show up the next day in Columbia and ATT would have switches all their numbers to route to Columbia instead of Charlotte.
Since the Cisco Phones were soft, when the employees logged into their phones and their existing numbers and voice mail settings would get downloaded to the phones in Columbia and they could operate without issue.
I would bet the CME, NYSE, and NASDAQ have disaster recovery sites in red states that would allow them to move in 24-48 hours without an issue, make the move over a weekend and the public would never know the difference.