evidence: Proposals in the budget include boosting the top capital gains rate for income over $1 million, eliminating the so-called "step-up in basis" loophole, expanding who has to pay investment income tax and at what rate, and bumping up the corporate tax rate. [...] Eliminating the "step-up in basis" would hit family businesses. Biden is once again floating the idea of ending the "stepped-up basis" rule that allows preferential tax treatment for assets held until death.