The billionaire, who is serving President Trump as an unpaid “special government employee,” will file a confidential report on his financial interests, according to a White House official.

Treasury Secretary Scott Bessent gave Mr. Musk’s representatives at the so-called Department of Government Efficiency a powerful tool to monitor and potentially limit government spending.

The tech billionaire and top Trump ally visited the General Services Administration, which appears to be a key part of his crusade to cut the cost of government buildings.

Michael Grimes, a top banker at Morgan Stanley, would become the latest leading tech figure to join the Trump administration, as a senior official at the Commerce Department.

The rebranding of a former White House digital office into the new Department of Government Efficiency signals its potential limits, budget experts said.

The billionaire decided he could not campaign while helping lead the so-called Department of Government Efficiency, but tensions with Elon Musk were also evident.

The world’s richest man had been expected to be situated in the Eisenhower Executive Office Building, but a West Wing office would give him closer access to President Trump.

The party symbolized the euphoria of the tech industry on the cusp of the Trump presidency. The guest list included Mark Zuckerberg, Sam Altman, Miriam Adelson and the vice president-elect, JD Vance.

Negotiations over an 836,000-square-mile island may fall to a close friend of Elon Musk with experience in deal-making. Just not that kind of deal-making.

The elite of Silicon Valley are set to revel in their new clout during a long weekend of inaugural parties as President-elect Donald J. Trump is set to resume power.

Mark Zuckerberg, the Meta chief executive, is one of several tech leaders expected to play a high-profile role in celebrating the new administration next week.

Mr. Musk has turned to Silicon Valley to help recruit executives who will take up unofficial positions across the federal government.

The social networking giant will stop using third-party fact checkers and instead rely on users to add notes to posts. President-elect Trump and his conservative allies said they were pleased.

The president-elect has raised more than $170 million for his swearing-in, an inaugural record, as wealthy Americans flock to curry favor with him and some give money even without the prospect of V.I.P. access.

The social networking giant will stop using third-party fact checkers and instead rely on users to add notes to posts. It is likely to please President-elect Trump and his conservative allies.

The president-elect has boasted about the donations for his inauguration, library and political activities from those seeking favor or perhaps in some cases, atonement.