Shares in Tesla plunged 6.79% Monday after its CEO Elon Musk said he is forming a new American political party, provoking an irate response from President Donald Trump. Shares in Tesla (TSLA) had dropped as much as 7.

Donald Trump fell in love with Elon Musk when the richest man in the world bankrolled his reelection campaign. Then he fell out of love with Musk when the tech titan openly criticized his ‘Big Beautiful Bill.

Musk, who has been floating the idea of creating a third political party for weeks in the wake of his split with the president, reignited the push over the weekend after the passage of Trump's sweeping tax cut and spending bill -- which Musk railed against over its estimated impact adding trillions to the national debt.