Tesla shares fall as CEO Elon Musk says he plans to form a new political party after reigniting a feud with President Donald Trump over the tax-and-spending bill that was signed last week.

Chief Executive Elon Musk said Saturday he had [created a new political party](

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Mr. Musk’s involvement in politics and his financial support for the president’s campaign was once seen by investors as a benefit to Tesla, fueling a steep rise in company shares after the election last year. That association has now turned into a liability. Tesla shares are down 40 percent from their peak in December.