Exiting the Big-12 is a complicated process and there are two and potentially three exit fees.

The first just leaving the Big-12. The cost to to do that is 27 months notice and twice the most recent media payout per member. Currently that is 40.9 + 40.9 million or 81.8 million dollars. Conference membership is perpetual.

If you want to shorten that exit period, the premium is variable but according to conventional wisdom from the comments made by the Big-12 offices, this figure is between 50% and 75% of the exit fee. So, something on the order of an additional 40.9 million to 61.35 million.

Then there is the issue of your grant of media rights, which are separate from conference membership. How much an exiting member would be forced to pay to the Big-12 to buy their media rights back would depend on how long was left in the current contract and what the value of that contract was on a per year basis. Presently, that is 40.9 million.

This is why Texas and Oklahoma are having such a hard time leaving. It is costing them:

Exit Fee: 81.8 million
Premium Fee to leave by June 30, 2023: 40.9 million
Buying back their media rights for 23/24 - estimated 42.7 million and 24/25 - estimated 45 million.

The grand total assuming there is no complications, of which there have been plenty, is:

81.8 + 40.9 + 42.7 + 45.0 = 210.4 million EACH.

So, any school wanting to leave the Big-12 had better have a hefty bank roll or friends with deep pockets. This is why the WVU to the ACC chatter is nothing more than noise. No one is leaving the Big-12, except Texas and Oklahoma and while it may be that they pay less than the above, it is going to hurt even if it comes down a considerable margin.