U.S. media outlets report that 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.

“When it comes to bankrupting our country with waste & graft, we live in a one-party system, not a democracy,” Trump’s former “first buddy” said on his social media platform, X, according to CNN.  “Today, the America Party is formed to give you back your freedom.”

CNN reports that Musk, the largest individual donor to Trump’s 2024 presidential campaign and, until recently, a close adviser to the president who spearheaded his administration’s push to cut government waste, had criticized Trump’s “big beautiful bill” because of estimates that it would add trillions of dollars to the federal deficit.

Meanwhile the BBC reports that it is unclear if the party has been formally registered with US election authorities.  Musk, who was born outside the US and is ineligible to run for the US presidency, does not say who will lead it.

He reportedly first raised the prospect of forming a party during his public feud with Trump, which saw him leave his role in the administration and engage in a vicious public spat with his former ally.

Musk was Trump’s main campaign financier during the 2024 election, and led the Department of Government Efficiency from the start of the president’s second term, aimed at slashing government spending.

The two have since fallen out spectacularly over disagreements about the “Big, Beautiful Bill”, which was narrowly passed by Congress and signed into law by the president last week.

The massive law includes huge spending commitments and tax cuts, and is estimated to add more than US$3 trillion to the US deficit over the next decade.

Crucially for Musk, who owns electric-vehicle giant Tesla, Trump's bill does not focus on green transition or subsidies for products like Tesla.

Elon Musk owns electric-vehicle giant Tesla, SpaceX, which launches rockets for the US government, and Starlin, which provides satellite service for US and European defense forces.