The announcement from Musk comes a day after Trump signed a tax-cut and spending bill into law, which the billionaire had fiercely opposed.

Billionaire Elon Musk said Saturday he is forming a third political party, after a dramatic falling out with Donald Trump, indicating he will make good on threats he made if the president’s domestic policy bill became law.

The tech billionaire, who has publicly feuded with President Trump, wrote on social media that he would be creating “the America Party,” though he hadn’t yet filed paperwork.