The breach with Trump was sparked by Musk’s criticism of a Trump-backed spending bill.
Musk has sought to rally opposition, arguing that it will add too much the government’s debt load. He has also been critical of Trump’s tariffs, which he said on Thursday would cause an economic recession in the second half of the year.
Trump said Musk’s welcome at the White House was wearing thin and accused him of being unhappy about the elimination of a tax credit for electric vehicles, which has been key to Tesla’s sales in the US.
The two men have also clashed over Trump’s decision to withdraw his nomination of Jared Isaacman, a Musk ally, to lead Nasa.
Thursday’s fall put the company’s share price at its lowest level since May, erasing gains that had been made on hopes that Musk would refocus attention on the company.
Tesla shares are currently down 25% since the start of the year, but are still up 60% over the past 12 months.
As the two men went at it, investors watched in disbelief.
“Can someone please take the phone away from him,” wrote, external investor Ross Gerber, who has been vocal about his concerns about the impact of Musk’s politics on Tesla and cut back his holdings. “Tesla is getting destroyed.”
