Billionaire Elon Musk said Wednesday that his time as formal adviser to President Donald Trump is coming to a close, raising questions about the future of the Department of Government Efficiency effort he spearheaded.

Elon Musk has officially left the Trump White House, capping a turbulent effort to slash the federal government by the world's richest man.

The world's richest man is making his views on a variety of subjects well known in Washington as he returns his attention to his many businesses, including Tesla and SpaceX.

Elon Musk expressed dissatisfaction with President Donald Trump’s giant tax bill, saying it undercut his efforts to slash government spending. Musk, who has announced he’s stepping back from his Department of Government Efficiency — a body that quickly became an exponent of the second Trump administration’s vision — told CBS News in an interview that he was “disappointed to see the massive spending bill,

The more significant surprise over the past decade has been the shift in Musk’s politics and his controversial rise to prominence in that sector, from his purchase and pivot of Twitter to X to his chainsaw-wielding antics at the head of the Department of Government Efficiency earlier this year.

Neuralink last year received "breakthrough device" clearance from the U.S. FDA. Three people have so far received implants made by Neuralink.

President Donald Trump dismissed criticism from Elon Musk, his billionaire donor and adviser, over the cost of his signature tax bill, telling reporters on Wednesday that compromises were made to secure the necessary votes.