July 7–8, 2025: The first trading day since Musk’s weekend announcement, Tesla shares tumbled, and Musk’s personal fortune dropped by as much as $15 billion, according to the Bloomberg Billionaires Index. As of July 9, it stands at $349 billion with Tesla shares broadly unchanged.

Mr. Musk’s involvement in politics and his financial support for the president’s campaign were once seen by investors as a benefit to Tesla, fueling a steep rise in company shares after the election last year. That association has now turned into a liability. Tesla shares are down 40 percent from their peak in December.