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 blasted Elon Musk’s bid to start a new political party, as the intensifying feud between the former allies deepens concerns among investors over the implications for Tesla Inc.

President Donald Trump on Sunday called Elon Musk's plans to form a new political party "ridiculous," launching new barbs at the tech billionaire and saying the Musk ally he once named to lead NASA would have presented a conflict of interest given Musk's business interests in space.

Dan Ives, an analyst with Wedbush Securities, wrote that Musk's continued push into politics was "exactly the opposite direction" investors wanted to see.

U.S. President Donald Trump on July 6 commented on tech billionaire Elon Musk’s plan to create a new political party, calling it “ridiculous” and warning that third-party movements have historically failed in the United States.

With talks stalling and just three framework agreements announced, President Donald Trump is now planning to set some countries' tariff rate by letter and pressuring its larger trading partners to finalize a deal by August.

President Donald Trump dismissed Elon Musk’s plan to launch a new political party, calling it “ridiculous” and insisting the U.S. remains a “two-party system.” “Third parties have never worked, so he can have fun with it,