Biden Expresses Support forAnnual Tax on Billionaires’ Unrealized Gains

WASHINGTON—President Biden expressed support for a proposal under consideration in the Senate to place an annual income tax on billionaires’ unrealized capital gains.

The potential tax increase, being pursued by Senate Finance Chairman Ron Wyden (D., Ore.), would be among a number of tax provisions that Mr. Biden is seeking to pay for a proposed $3.5 trillion spending plan that encapsulates much of his first-term agenda. It is an alternative to some administration tax ideas that have flopped in Congress, and it would generate money from the wealthiest sliver of Americans, whose incomes can be a fraction of their wealth.