If they dilute shares down dramatically it will remove institutional interest due to share price being too low. They are better off simply exercising their 80% stake. They hurt themselves and shareholders if they dilute more than that. Why is 80% not enough for the government? It is $200b+ not to mention everything they already received(all profits swept, damages from TBTF lawsuits, and deals struck for low income). If they release with reasonable terms that will boost GDP quite a bit and will increase tax income too. There is no reason they should feel the urge to wipe out all the retail investors just because Ackman has been invested in this for over a decade and he might make some money too.