The proposed California Billionaire Tax has already got a lot of people opening their wallets — to fight the tax.
The proposal has positioned organized labor and progressive lawmakers against powerful figures in tech and business, as well as Gov. Gavin Newsom. The measure would impose a one-time 5% levy on the net worth of California residents with a net worth of at least $1 billion — affecting roughly 200 people. Backers are aiming for the November ballot and are gathering signatures to qualify.
Proponents estimate that the measure would generate $100 billion in revenue, with 90% earmarked for healthcare and 10% for education and food assistance.
The proposal has galvanized a cross-partisan set of politicians and ultra-wealthy Californians. They have spun up several groups dedicated to defeating the tax, with competing measures that could make November’s ballot one of the most confusing in years.
Here’s a rundown of the biggest supporters and detractors so far.
Pro-Billionaire Tax
Service Employees International Union – United Healthcare Workers West (SEIU-UHW)
As the main sponsor of the 2026 Billionaire Tax Act ballot measure, SEIU-UHW is spearheading the effort to tax the wealth of California’s richest residents. The union has committed $25 million to campaigning for this and two other measures. It plans to hold rallies and run ads between now and Election Day.
The campaign has until June 24 to gather 875,000 signatures to qualify the proposal for the November ballot. Then it has to convince a majority of voters to agree. The union says it has already gathered 25% of the necessary signatures.
Teamsters California has endorsed the proposal. Democratic gubernatorial candidate Tom Steyer, himself a billionaire, has also come out in support of the measure. And Vermont Sen. Bernie Sanders led pro-tax rallies in Los Angeles and San Francisco last month.
Rep. Ro Khanna surprised many in Silicon Valley, which falls within his district, when he came out in support of the measure. This prompted outrage in tech circles, and several wealthy executives are backing Ethan Agarwal, the millennial tech founder running (opens in new tab) for Khanna’s seat.
Anti-Billionaire Tax
Building a Better California
This political action committee, officially formed in January, has emerged as a major anti-tax group for tech executives and other business leaders. The group, focused on regulatory reforms that would ameliorate the state’s housing crisis, is also sponsoring three tax-related initiatives that, if they qualify for the ballot and are approved by voters, would compete with various parts of the billionaire tax. Building a Better California is paying a whopping $15 bounty for signatures on its proposals (more than three times the going rate last fall).
Building a Better California has reported $35 million in contributions, with $20 million donated by Sergey Brin, co-founder of Google. Other supporters include former Google CEO Eric Schmidt ($2 million), Stripe CEO Patrick Collison ($2 million), and venture capitalists John Doerr ($2 million) and Michael Moritz ($2 million). Moritz is also chairman of The San Francisco Standard.
California Business Roundtable Issues PAC
The California Business Roundtable, which represents many of the state’s largest employers and business interests, has given money to Californians Against Higher Taxes, the campaign committee formed in 2022, to defeat the proposed wealth tax measure.
Rob Lapsley, president of the CBRT, said the group will ramp up its initiatives if or when the wealth tax is approved for the ballot. “We’ve been mobilizing since September — the day we knew this was real, we started this opposition campaign,” he said. “Our research — and it’s expensive, to be clear — shows that we can defeat this. I can tell you the coalition is going to be big.”
Recent donors to the CBRT include Peter Thiel ($3 million), Chris Larsen ($500,000), and Alex von Furstenberg ($200,000).
Golden State Promise
This PAC was created specifically to oppose the proposed wealth tax initiative and is funded solely from figures tied to Ripple, including a $5 million contribution from Ripple Executive Chairman Chris Larsen and another $5 million from Ripple Labs. The PAC is staffed by consultants from the crypto super PAC Fairshake, alongside former Democratic consultants Roger Salazar and former Bernie Sanders strategist Ben Tulchin.
Salazar said the group would not be supporting any ballot initiatives against the wealth tax, but would be “running an eight-figure, statewide communications campaign to talk to voters.” The message: The billionaire tax would “hurt the very people it’s trying to help: working people, middle-class families, small businesses, those types of folks.”
“Is this good for California? No, it’s terrible for California,” Larsen told The Standard. “People are unhappy with the general economy. And who do we take it out on, regardless of whether it’s good or bad for the state?” Billionaires, he implied. “And that’s unfortunate. There needs to be a counterforce for some of the things that are destructive to the state.”
Stop the Squeeze
Established by political strategists Dan Newman and Brian Brokaw, who previously worked on Newsom’s ballot campaigns, Stop the Squeeze was created to oppose the proposed wealth tax measure. The group has drawn support from prominent Democratic donors, including San Francisco venture capitalist Ron Conway ($100,000) and Daniel Tierney, a venture capitalist at Wicklow Capital in Chicago ($200,000). Bokaw said the committee will release an economic impact report on the potential effects of the wealth tax in the coming weeks.
“I don’t want to get into all the tactics yet,” he said. “We have seen from our research that the more voters learn about this measure, the less likely they are to support it. Whether they’ll sign a petition at the Safeway parking lot or vote for it down the road, we know that voter education on what this will actually [be] is the critical piece of this.”