"Harris seems to be making a policy choice based on the disproven, failed ideology of trickle-down economics, and giving petulant billionaires a gift in the process," said one progressive advocacy group.

Democratic nominee Kamala Harris broke with President Joe Biden on Wednesday by proposing a smaller capital gains tax increase for wealthy Americans, a decision that one progressive advocacy group decried as a "baffling capitulation to Wall Street billionaires" who have vocally complained about the vice president's embrace of higher taxes on the ultra-rich.

Harris said at a campaign event in New Hampshire on Wednesday that "if you earn a million dollars a year or more, the tax rate on your long-term capital gains will be 28% under my plan," broadly confirming earlier reporting by The Wall Street Journal.

A 28% top tax rate on long-term capital gains—profits from the sale of an asset held for more than a year—would be significantly lower than the 39.6% rate that Biden proposed in his most recent budget.