Under current rules, whoever inherits the Amazon shares Bezos bought in 1994 for $10,000, worth $180 billion today, will receive a so-called step-up in basis, wiping out any capital gains tax liability. Biden’s plan would close that loophole and apply the top capital gains tax immediately when assets transfer to wealthy heirs. If the rate increases -- it’s 20% for holdings like Bezos’s, and Biden has called for boosting it to 39.6% -- the eventual tax bill would too.
For Bill and Melinda Gates, who announced on Monday that they would be divorcing, a change in the step-up rule might be less costly. The Gates fortune, valued at $145.8 billion, is older, and they’ve already sold or donated much of their stake in Microsoft Corp. But $26 billion of Microsoft shares remain, and it isn’t clear how the couple will manage their assets in a split.
Congress estimates that stepping up the tax basis of inherited assets costs the government about $43 billion a year. Ending that practice and raising the rate would amount to the biggest curb on dynastic wealth in decades, altering an American economic landscape dominated by a few wealthy families.
https://www.bloomberg.com/news/articles/2021-05-04/biden-tax-rule-would-rip-billions-from-biggest-fortunes-at-death