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.

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.

Elon Musk said he’s carrying out his threat to form a new political party after his fissure with President Donald Trump, announcing on social media that he would form the America Party in response to the president’s sweeping tax cuts law.