That's not how this works... If you buy something for $10m you're out $10m. Yes, when you donate it you can write off those $10m, or present value at the day o

That's not how this works... If you buy something for $10m you're out $10m. Yes, when you donate it you can write off those $10m, or present value at the day of the donation. But you're only saving the taxes on those $10m of income, so you're still down $5m (assuming a 50% tax rate). And you could just as easily donate those $10m directly, and get the same tax write-off.