The change also could trigger a short-term burst of giving by donors who benefit from today’s tax rules and want to take advantage of them before the changes take effect
Another way the proposal could spur more giving is that is that some wealthy people might want to give enough away to stay under the $100 million annual threshold,
people would be less likely to hold on to their assets if they have to pay taxes every year on the increase in value.
he wealthiest people often have extremely complicated, long-standing financial arrangements, including philanthropic planning that could negate any benefits for donating more under a billionaire’s tax.
Owens also noted that current tax law caps charitable deductions at 60 percent of adjusted gross income. If that provision remains in effect, wealthy people who hit that cap even before a billionaire tax is imposed may see no tax benefit from additional giving,
Economists who study taxes on the ultra wealthy say they think people overestimate the impact of new taxes on charitable giving.
“Sometimes people get the false impression that philanthropy actually is a roundabout way to save money on taxes that exceeds the cost of the gift, and that just isn’t true,” says Duquette. “If you give your money away, then even if you do get some tax benefits, you still have less wealth than you did when you started, so that’s not really a reason why philanthropists do philanthropy.”