Set your assumptions
Why apples-to-apples matters
Total U.S. charitable giving reached $617 billion in 2025. Set against that number, $60–150 billion in new tax revenue looks modest — a fraction of American generosity. But the $617 billion belongs to millions of households, foundations, corporations, and bequests. It is not the billionaires’ number.
The billionaires’ number is on the order of $20–40 billion a year. Megagifts — individual gifts of $600 million or more — totaled about $19.2 billion in 2025, and a single donor accounted for roughly a third of that. The total swings year to year because a handful of very large gifts dominate it.
Compared against the right denominator, the result inverts: the two tax changes would raise two to five times what billionaires currently give — every year, without depending on anyone’s mood, mortality, or reputation strategy.
The substitution test
The standard defense of philanthropy-over-taxation rests on two claims: private allocation is more efficient than public allocation, and voluntary giving substitutes for what the forgone revenue would have funded. The second claim is the load-bearing one. Without it, “let them give voluntarily” just means “let these things go unfunded.”
The substitution claim is currently being tested in public. As funding for education, infrastructure, and health programs retreats, philanthropy is not filling the gap — and structurally cannot. The scale is wrong: $20–40 billion against drawdowns running to hundreds of billions. The direction is wrong: donor money flows to named buildings, endowed institutions, and legible prestige projects, not water systems, Title I schools, or reimbursement rates. Giving follows donor preference; the gaps follow political neglect. The two maps do not overlap.
Note what this argument does not need. It does not need to show that government allocates better than donors — only that voluntary giving does not and cannot replace what the revenue funded. A defender can retreat to the efficiency claim, but efficiency without substitution is not a defense of philanthropy as a system; it is a general complaint about government that would hold whether billionaires gave or not. What remains is revenue against revenue — and the ratio above answers that.
The tax estimates still carry real uncertainty. The top-rate figure depends on behavioral response — income shifting, realization timing, avoidance — and the loan-tax figure depends on how much equity-backed borrowing survives the tax that targets it. The bands in the chart are the argument’s honest width. That is why they are adjustable.