evidence: - The "step-up basis" loophole lets billionaires pass down investment gains without paying any taxes. [...] Many of the solutions are simple. House Democrats and the Biden administration both support higher taxes on rich Americans and corporations. But one particular tax issue — the "step-up basis" — sits at the center of their hemming and hawing. [...] Biden wants inheritors to pay taxes on gains larger than $1 million for single filers and $2.5 million for couples. Coupling that with a higher capital gains tax rate could raise more than $320 billion over the next decade, the White House said.