Sergey Brin's $102 Million Fight Against California's Prop 40
Google co‑founder Sergey Brin has spent $102 million to oppose California's wealth‑tax Proposition 40, building a political group that could shape state policy for years.
Google co‑founder Sergey Brin has poured $102 million into Building a Better California, a political group created to fight California’s proposed wealth‑tax ballot measure, Proposition 40. The organization has already spent more than $304 million on a suite of related propositions, turning Brin’s personal opposition into a lasting political infrastructure that could shape state policy for years.
What happened
In early 2026 Brin founded Building a Better California, seeding it with $20 million. By August, his contributions topped $102 million, according to campaign‑finance filings. The group channels money from Silicon Valley billionaires and venture‑capital leaders into ballot‑measure campaigns.
Through Oct. 20, the organization has spent $304 million on four propositions:
$118.5 million to defeat Proposition 40, a one‑time 5 % tax on assets over $1 billion aimed at raising tens of billions for healthcare, education and food assistance.
$186 million to support Propositions 41 and 42, which would block the wealth tax by limiting new tax exemptions and outlawing retroactive taxation.
$10 million backing Proposition 45, targeting California’s environmental‑review process.
$6 million for Proposition 37, creating a $25 billion home‑buyer loan fund.
Politico’s analysis shows that more than 70 California billionaires have poured a record $612 million into state elections this cycle, with at least 30 contributing over $293 million specifically to the wealth‑tax fight.
Why it matters for investors and consumers
Brin’s campaign illustrates how ultra‑wealthy donors can use ballot measures to shape fiscal policy that directly affects corporate tax burdens and public‑service funding. If Proposition 40 were to pass, the projected revenue—tens of billions over several years—could offset federal healthcare cuts, potentially reducing the need for state‑level tax hikes elsewhere. Conversely, a defeat could keep the tax base intact, preserving the disposable income of high‑net‑worth individuals and the profitability of tech firms that rely on California’s talent pool.
Investors watch these battles because they signal future regulatory environments. A successful wealth‑tax block may keep California’s business‑friendly climate, supporting venture‑capital activity and tech‑sector growth. On the other hand, a passage could lead to higher state taxes on corporate profits and employee compensation, influencing hiring decisions and cost structures for companies operating in the state.
Consumers could feel indirect effects through public‑service funding. The wealth tax earmarks 90 % of proceeds for healthcare, a sector already strained by federal cuts. If defeated, California may need to find alternative financing, possibly affecting Medicaid eligibility or education budgets.
What’s next
The ballot will be decided on Nov. 3. Voters will see a “yes” or “no” on Proposition 40 alongside Propositions 41, 42, 45 and 37. The outcome of any one of these measures could nullify the wealth tax, even if a majority backs it, according to the Legislative Analyst’s Office.
Key factors to watch:
Voter turnout in the November election, especially among high‑income precincts that historically lean against new taxes.
Additional fundraising by Building a Better California in the final weeks, which could shift the balance in close races.
Public messaging from labor groups, such as the Service Employees International Union‑United Healthcare Workers West, which continue to promote the tax as essential for healthcare funding.
For readers interested in the broader political context, see our guide on how to vote in the 2026 midterms, which explains the ballot‑measure process in California.
Background on the wealth‑tax proposal
Proposition 40 would levy a 5 % tax on the assets of individuals and trusts valued over $1 billion as of Jan. 1, 2026. The measure is designed to generate revenue to offset federal cuts to Medicaid and other health programs, with 90 % earmarked for healthcare and the remaining 10 % split between education and food‑assistance programs. The proposal is backed by progressive leaders, including Sen. Bernie Sanders and Rep. Ro Khanna, and was sponsored by the SEIU‑UHW.
Brin, whose net worth Bloomberg estimates at $231 billion, has publicly opposed the tax, likening it to “socialism” he witnessed in the Soviet Union. He relocated to Nevada before the Jan. 1 residency cutoff, a move that would exempt him from the tax if it passed.
Long‑term political infrastructure
Beyond the immediate ballot fight, Building a Better California is positioning itself as a permanent hub for billionaire political activity in the state. By coordinating contributions from figures like Kleiner Perkins chair John Doerr, former Google CEO Eric Schmidt, Stripe CEO Patrick Collison and former Sequoia partner Michael Moritz, the group can mobilize resources for future policy battles, from tax legislation to environmental regulation.
Analysts suggest that this infrastructure could influence California’s fiscal direction for the next decade, affecting everything from corporate tax policy to public‑service funding, and thereby shaping the investment climate for tech and venture‑capital firms that dominate the state’s economy.
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