Very interesting. Thanks for the link.
So basically - Panthers pay $17 mil for a five year extension. At the option of Broward County, the Panthers can be extended for two five year periods, at a cost of $17 mil from the Panthers to Broward for each extension. Then as mentioned, the Panthers have development rights to the parking lot for the next five years (subject to Broward County's approval).
So this is where I think I got the situation all wrong. I would've thought that the Panthers had all the leverage here - they could move in four years, so they'd try to extract as many concessions from Broward County as they could. I've heard numerous times that the Panthers arena is not in a desirable location. Instead it seems like the Panthers are quite eager to stay, to the tune of up to $51 million.
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Actually - I take that back. Under the agreement Broward County is paying $25 mil per year to the Panthers (reduced to $20 mil per year in the second extension). That is obviously very favourable to the Panthers! That seems to just be a continuation of the existing lease terms though. So that adds up to much more than the $51 mil the Panthers are paying back. So I can now understand why the Panthers are more eager to stay.