On a Saturday morning in December 2022, Elon Musk summoned finance executives at Twitter, which he had bought six weeks earlier, to a conference call. Then he drilled into a spreadsheet that contained the social media company’s expenditures.

Musk has emerged as a prominent member of Trump's inner circle. Tesla has lobbied for electric vehicle subsidies and other benefits over the years.

The billionaire Tesla CEO is in a stronger position to influence development of federal rules that would put more of the fully self-driving cars on the road.