I don't think you understand how taxes work. Donating $55M doesn't offset owing $55M in taxes. It reduces your cap gains by $55M, and that's not the same thin

I don't think you understand how taxes work. Donating $55M doesn't offset owing $55M in taxes. It reduces your cap gains by $55M, and that's not the same thing. They'd still owe taxes on the $85M cap gains you describe.