Democrat James Talarico won the Texas Senate race, a result that the BBC says dealt a major setback to Republicans and to Elon Musk. The seat had not gone to a Democrat since 1988.
According to the Financial Times, Musk's political action committee gave $47 million (£35 million) to Republican candidate Ken Paxton's campaign. The billionaire had also given $158 million to the Senate Leadership Fund in September. The money was not enough to keep the seat Republican.
In his acceptance speech, Talarico said: "We just proved that all the money in the world is no match for the people of Texas."
Musk wrote on X: "Guess my election-interfering space lasers didn't work this time." The BBC reports that Tesla shares fell 4.9% and SpaceX shares fell 3.4% on Wednesday morning, while stocks broadly rose after the election.
The BBC also reports that Musk became the top individual donor in this year's midterms, with an estimated $446 million supporting Republican candidates. His money went through super PACs, which can raise unlimited sums but cannot give directly to candidates or coordinate with their campaigns.