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.

Recent social media barbs between the president and the EV maker’s chief executive have investors worried again. Here’s the latest.