Shares in Tesla tanked by as much as 7.6% in premarket trading Monday after its CEO Elon Musk said he is forming a new American political party, provoking an irate response from US President Donald Trump.

President Donald Trump took aim at Elon Musk after his former adviser announced the creation of a new political party following staunch opposition to the president's signature legislation.

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.