Elon Musk’s bitter falling-out with President Trump could be costly for Tesla. As long as he is persona non grata in the Trump administration, Mr. Musk, the chief executive of Tesla, will struggle to persuade Republicans not to gut climate policies worth billions of dollars to the electric car and battery company.

Musk attacked Trump directly over his signature spending bill for the first time Thursday, sparking an explosive back-and-forth.

Shares of Elon Musk’s electric vehicle maker are falling sharply Thursday as investors fear his dispute with Donald Trump could end up hurting the company.