"Buy, borrow, die" is real, legal, and much smaller than advertised

The leverage is at records — FINRA margin debt hit roughly $1.4T in July, up 38.6% year-on-year. But the Yale Budget Lab, citing Liscow and Fox, finds borrowing is only about 1% of income for the top 0.1% by net worth. Total borrowing by the ultra-wealthy runs around $260B, of which perhaps $140B is attributable to unrealised gains. About 35,000 households would be covered by a borrowing tax — and roughly half the revenue comes from about 400 people.

The part doing the work is step-up in basis at death, not the loan. Anyone selling this as a replicable strategy at a $5–50M net worth is selling something.