Elon Musk reigniting his feud with the president is "stupid," according to longtime Tesla investor Ross Gerber.

The feud reignited on Monday when Musk, who spent hundreds of millions on Trump's re-election, renewed his criticism of Trump's tax-cut and spending bill, which would eliminate subsidies for electric vehicle purchases that have benefited Tesla, the leading U.S. EV maker. That bill passed the Senate by a narrow margin midday Tuesday.

Joe Gebbia, a confidant of the technology billionaire and a Tesla director, is also a leader of the federal cost-cutting team. The fight might put him in a bind.