By Christian Leonard,Staff WriterUpdated April 12, 2026 9:05 a.m.
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Candidates and their supporters have aired political ads more than 1.3 million times since the start of 2025, according to data from advertising researcher AdImpact.Benjamin Fanjoy/For the S.F. Chronicle
Tom Steyer and Matt Mahan are running on housing and education. Eric Swalwell and Antonio Villaraigosa are running against Donald Trump.
The candidates for California governor are spending millions of dollars on ads to define themselves against these issues — and more.
Candidates and their supporters have aired political ads more than 1.3 million times since the start of 2025, according to data from advertising researcher AdImpact. The Chronicle analyzed data from those ads to determine how much money each campaign has spent on blanketing airwaves and streaming services, and which topics come up most often.
Billionaire and former hedge fund manager Tom Steyer has poured by far the most money, most of it from his own pocket, into advertisements. As of April 9, he’d spent roughly $89 million on more than 1 million ad airings, becoming a regular feature in Californians’ commercial breaks and social media feeds. The ads had drawn about 2.9 billion views among people ages 35 and above, according to AdImpact’s estimate.
Steyer’s campaign has been so expansive that he’s spent more than $1 million on ads that, by AdImpact’s measure, reached zero people. Almost all of those ads aired around midnight.
Other candidates’ ad spending similarly matched the size of their campaign funds. San Jose Mayor Matt Mahan, and a few third-party groups backing his campaign, spent about $12 million on airings, while Rep. Eric Swalwell — whose campaign is now in doubt among allegations of sexual assault — spent more than $5 million.
Candidates for the 2026 CA governor election, by money spent on ads
Among ads run from 2025 onward, with views among people 35+. Data includes ads run by the candidate and groups supporting them
Tom Steyer spent by far the most money, at nearly $90 million and getting 2.9 billion viewers. He was followed by Matt Mahan, who spent $12 million and received about 290,000 viewers.
| Candidate | Estimated views | Spent |
|---|---|---|
| Tom Steyer | 2.9B | $89M$89M$89M |
| Matt Mahan | 289M | $12M$12M$12M |
| Eric Swalwell | 139.8M | $5.2M$5.2M$5.2M |
| Antonio Villaraigosa | 79.3M | $1.6M$1.6M$1.6M |
| Xavier Becerra | 32.7M | $1.5M$1.5M$1.5M |
| Katie Porter | * | $239K$239K$239K |
| Betty Yee | 12.1M | $216K$216K$216K |
| Steve Hilton | * | $465.3$465.3$465.3 |
*Viewer estimates were not available for Katie Porter or Steve Hilton.
Table: Christian Leonard / S.F. ChronicleSource: AdImpact
Some candidates, including former U.S. Rep. Katie Porter and former state Controller Betty Yee, have spent much less money on advertising, though the data doesn’t include the videos they’ve posted to their own social media accounts. Conservative commentator Steve Hilton spent less than $500 on a series of social media videos, according to the data. Fellow Republican and Riverside County Sheriff Chad Bianco recorded no ads.
Because Steyer has run by far the most advertisements, the issues he brings up — including housing and utility costs — dominate the candidates’ overall screen time. But pro-Mahan ads also often center on housing. In fact, 43% of all candidates’ ads that aired between the start of 2025 and April 9, 2026, mentioned the topic.
Issues in the 2026 CA governor election, by how often ads mention them
For every time an ad was run from 2025 onward. Data omits ads run by candidates who have dropped
Housing is by far the most-often-mentioned issue in the race, with 43% of ads referencing it. It’s followed by education and energy at 38% and 27% respectively.
AdImpact’s data only includes up to three issues mentioned in an ad, meaning some topics may go uncounted if the ad references more issues than that.
Still, there are some general patterns in the issues some candidates return to. Yee and Porter, for example, have been more likely than other candidates to criticize lobbying and special interest influence. Swalwell, former Los Angeles Mayor Antonio Villaraigosa and former California Attorney General Xavier Becerra have put opposition to Trump at the forefront of many of their videos.
Issues in the 2026 CA governor election, by how often ads mention them
Mentions across all ads run by each candidate and their supporters from 2025 onward
Table showing how often campaign ads for candidates in the 2026 California governor’s race mention key issues, based on ads run since 2025. Mentions vary widely by candidate: Antonio Villaraigosa frequently references immigration (73%) and Donald Trump (72%), while Eric Swalwell and Xavier Becerra mention Trump and immigration in nearly all ads; Steve Hilton focuses almost entirely on the economy (100%), and Betty Yee’s ads emphasize Trump and special interests (both 100%) with little mention of other issues.
| Candidate | Housing | Economy | Special Interests | Immigration | Donald Trump | Other |
|---|---|---|---|---|---|---|
| Tom Steyer | 44% | 36% | 18% | 16% | 15% | 74% |
| Matt Mahan | 83% | 32% | 0% | 0% | 0% | 57% |
| Eric Swalwell | 0% | 5% | 0% | 95% | 100% | 95% |
| Antonio Villaraigosa | 19% | 49% | 0% | 73% | 72% | 50% |
| Xavier Becerra | 0% | 16% | 0% | 100% | 100% | 84% |
| Betty Yee | 0% | 0% | 100% | 0% | 100% | 100% |
| Katie Porter | 0% | 6% | 53% | 8% | 17% | 16% |
| Steve Hilton (R) | 0% | 100% | 0% | 0% | 0% | 0% |
AdImpact’s data lists up to three issues referenced by an ad, so some issues are undercounted.
Table: Christian Leonard / S.F. ChronicleSource: AdImpact
What’s not included in the table above are the ads run by “California is Not for Sale,” one of the few committees so far that have organized entirely in opposition to a candidate. The group, which is mostly funded by the California Association of Realtors, has spent roughly $1.8 million on attack ads against Steyer.
Some of the candidates have thrown a few punches, too. Steyer has spent roughly $1.5 million on airings of an ad attacking Swalwell, while Villaraigosa has spent a much smaller sum — about $17,000 — on Spanish-language ads criticizing Becerra.
April 12, 2026|Updated April 12, 2026 9:05 a.m.
Data Reporter
Christian Leonard is a data reporter for the San Francisco Chronicle. He joined the Chronicle in 2022 as a Hearst Developer Fellow. He previously worked as a senior staff writer at the Outlook News Group, a collection of community newspapers in Los Angeles County. He is a graduate of Biola University, from which he received a bachelor’s degree in journalism and integrated media, and interned at NBC Los Angeles.
