Billionaire investor and climate activist Tom Steyer has emerged as the dominant financial force in the 2026 California governor's race after pouring unprecedented sums of money into advertising across television, radio, streaming services, and social media. His campaign is now described as one of the most expensive state-level election efforts ever seen in the United States.
According to data compiled by ADImpact, Steyer has already spent or reserved more than $195 million (roughly £145 million) on political advertising ahead of California's June primary election.
