The most expensive campaign in California this fall is for a ballot measure that would impose a one-time levy on the state’s wealthiest residents, and the money moving against it is coming almost entirely from the people who would pay it.
CNBC’s Robert Frank reported that a group called Building a Better California has raised over $150 million so far and is backing two competing ballot measures designed to effectively kill the billionaire tax act. According to Frank, the group’s largest backer is Sergey Brin of Alphabet (NASDAQ:GOOGL | GOOGL Price Prediction), who has given $102 million, a figure Frank set against his characterization that Brin is worth $278 billion. The Los Angeles Times separately reported the Google co-founder has poured more than $100 million into the fight. Frank added that health care unions supporting the measure have spent over $30 million on their campaign.
What the Measure Actually Does
The proposal on the ballot is Initiative No. 25-0024, described in the “Billionaire Exodus and California Wealth Tax” research document as the 2026 Billionaire Tax Act. Frank described it as a one-time levy of 5% of the total net worth of California billionaires. The research document specifies it as a one-time excise tax at a 5.0% rate on individuals with net worth exceeding $1 billion, with proceeds pitched by proponents toward healthcare and education funding gaps.
Why Propositions 41 and 42 Are the Real Story
Frank walked through the ballot mechanics that most voters will not encounter until they open their ballots. Proposition 40 is the tax act itself, while Propositions 41 and 42 are competing measures that, if either receives one more vote than 40, would essentially nullify the billionaire tax act. A Californian who votes yes on 40 and also yes on Proposition 41 or Proposition 42 could cancel their own preference without knowing it. That is the strategic point of the opposition’s spending.
Frank said the polls are showing sort of a dead heat. Newer numbers complicate that picture. A UC Berkeley Institute of Governmental Studies poll found Prop. 40 holding a lead, and reporting this week indicates California voters back both the billionaire tax and the measures that could block it. Both can be true. Voters can favor taxing billionaires in principle while also endorsing measures that sound like protection for retirement savings or fiscal transparency. That contradiction is what makes the competing-measure strategy viable.
Huang Against Brin
Not every Silicon Valley fortune is on the same side. According to the research document, NVIDIA CEO Jensen Huang said he is “perfectly fine” with the 5% wealth tax, arguing that “living in Silicon Valley is a choice” and that the weather, talent pool, and innovation culture justify the taxes. The “Billionaire Exodus and California Wealth Tax” research document estimates the levy would cost him approximately $8 billion, according to Billionaire Exodus and California Wealth Tax (research document). Two technology fortunes, opposite conclusions.
Revenue Math In Dispute
Whether the measure would raise anything close to its advertised total is disputed. A Hoover Institution person-by-person analysis, as described in the “Billionaire Exodus and California Wealth Tax” research document, found nearly 30% of California’s billionaire tax base had already departed before the initiative qualified for the ballot, according to Hoover Institution, via Billionaire Exodus and California Wealth Tax (research document). The Hoover Institution analysis, via the research document, put the departed wealth at $536 billion, led by the Google and Meta cohorts, and the Hoover Institution analysis, via the research document, revised the projected one-time revenue down to approximately $40 billion from the original $100 billion projection cited by the Hoover Institution via the research document. Once the permanent loss of those filers’ future annual income tax payments is counted, the Hoover Institution analysis, via the research document, estimated the net present value of the wealth tax at negative $24.7 billion, according to Hoover Institution, via Billionaire Exodus and California Wealth Tax (research document). This reflects one named institution’s methodology and remains contested.
Legal exposure is another wild card. Analysts cited in the research document expect litigation in state and federal courts regardless of the November outcome, with retroactivity provisions and due-process questions among the identified vulnerabilities. For further background, the full initiative text is available through the California Attorney General’s initiative page.
What to watch between now and November: whether the ballot ordering and voter education around Propositions 41 and 42 shift, whether additional donors surface on either side, and whether the polling gap between principle and mechanics narrows once voters see all three measures listed together.