These people have fueled Mr. Musk and his businesses. Over the years, they’ve invested millions of dollars in SpaceX, Tesla, Neuralink, the Boring Company, X and xAI. Some have gained board seats or become close friends with Mr. Musk for their loyalty.

Steve Jurvetson

Mr. Jurvetson is a longtime Silicon Valley venture capitalist and was an early investor in Mr. Musk’s SpaceX, where he is a board member. He is also a superfan of Mr. Musk’s. On a podcast in 2020, he praised the billionaire for being “the greatest gift of the American dream living right now.”

Marc Andreessen

The venture capitalist is one of Mr. Musk’s big financial supporters in Silicon Valley: His firm, Andreessen Horowitz, has backed SpaceX, X and xAI.

Roelof Botha

A fellow South African, Mr. Botha was a member of the PayPal Mafia. Now, as the managing partner of Sequoia Capital, he oversees the venture firm’s various investments into Mr. Musk’s companies, including X and xAI.

Shaun Maguire

A partner at Sequoia Capital, Mr. Maguire led the firm’s deals into Mr. Musk’s SpaceX, X, xAI and the Boring Company, a tunneling venture. He has played a big role in Mr. Musk’s work during the presidential transition.

John Hering

Mr. Hering, a venture capitalist, invests in Mr. Musk’s companies and has become a trusted confidante. Recently, Mr. Hering has spent time in Palm Beach, Fla., helping with the presidential transition.

Peter Thiel

Mr. Thiel and Mr. Musk are members of the so-called PayPal Mafia, a group of founders and early employees of the payments company. While Mr. Thiel helped oust Mr. Musk from the company decades ago, he has recently become a political ally and supporter. Vice President-elect JD Vance once worked for Mr. Thiel’s venture capital firm, and Mr. Thiel was the one who introduced the running mates.

Larry Ellison

Mr. Ellison, the co-founder of Oracle, is a self-described good friend of Mr. Musk’s and has taken part in some Trump transition meetings. When Mr. Musk bought Twitter in 2022, Mr. Ellison committed $1 billion to the deal.