California will vote
on a billionaire's tax.
A continuously updated public resource on Initiative 25-0024, the 2026 Billionaire Tax Act. Donors, polls, prediction markets, and the strongest case on both sides. Read once. Check the terminal daily.
The question on the November 2026 ballot
On November 3, 2026, California voters will decide Initiative 25-0024, officially titled The 2026 Billionaire Tax Act. Some news outlets have nicknamed it CABTA. Whatever the label, the structure is precise. The Act adds Section 37 to Article XIII of the California Constitution and creates Part 27 of the Revenue and Taxation Code. Together those provisions impose a one-time excise tax on the net worth of California-resident individuals and trusts whose wealth equals or exceeds $1 billion.
The proponent of record is Suzanne Jimenez. Counsel is George M. Yin of the Kaufman Legal Group in Los Angeles. The most recent amendment, designated 25-0024 Amdt. 1, was filed on November 24, 2025 and received by the AG's office two days later.
The pitch: California has a structural revenue gap, a Medi-Cal program covering nearly 15 million low-income residents, and a public-education obligation that has been steadily underfunded. The Act's findings argue that around 200 California billionaires collectively hold more than $2 trillion in wealth and pay an effective tax rate (federal, state, and local combined) of roughly 24%, against an average California taxpayer rate of 30% (citing NBER Working Paper 34170 by Akcan Balkir, Saez, Yagan, and Zucman, 2025).
The pushback: constitutional questions, Prop 13 framing, domicile flight, the U.S. apportionment clause, and the LAO's warnings about California's already-volatile tax base. Every angle has a well-funded counter-argument. This site exists to make the entire case, on both sides, legible.
“An excise tax is imposed for tax year 2026 on the activity of sustaining excessive accumulations of wealth by applicable individuals with net worth of $1 billion ($1,000,000,000) or more.”
Section 50301(a), 2026 Billionaire Tax Act
What the Act actually says
Five things matter. They come straight from the ballot text, not from press coverage.
- Rate§50301(b)
5 percent of the net worth of the individual or trust. For individuals (other than a trust) with net worth between $1.0B and $1.1B, the rate phases in: it is reduced 0.1 percentage points for each $2 million by which net worth falls below $1.1B.
- Threshold§50301(a)
Net worth of $1,000,000,000 or more, measured as of the valuation date defined in §50308(o). A married couple is considered one individual for this purpose.
- Who pays§50301(a), §37(a)
Applicable individuals who are California residents within the meaning of Revenue and Taxation Code §§17014 and 17015.5 as of the tax obligation date. Trusts are also covered.
- How it’s paid§50301(c)
Two options. Pay in full with the 2026 income tax return, or pay in five equal annual installments. Each unpaid installment carries a 7.5 percent annual nondeductible deferral charge on the remaining balance.
- Where it goes§37(d), §16355
90 percent to the Billionaire Tax Health Account (Medi-Cal and safety-net providers); 10 percent to the Billionaire Tax Education and Food Assistance Account (K-14 and CalFresh / CalFood / Universal Meals). Annual appropriation caps: $22.5B health, $2.5B education and food.
Beyond the rate and the use of funds, the Act includes a long valuation chapter (Sections 50302 and 50303) that addresses how to measure private-business interests, trusts, art, real estate held via revocable trusts (excluded), and out-of-state tangible property (excluded if it sits outside California for at least 270 days during 2026). It carves out qualified pensions, allows up to $10M aggregate in Roth-type accounts, and provides a $5M de minimis for art, collectibles, and similar non-publicly-traded assets.
What the markets are pricing
Polymarket is the largest prediction market on this race. As of the last refresh, it prices ballot qualification at 76.0¢ and passage in November at 35.5¢. Volume on the “passes” market is around $3.1M, which is real money relative to other state-level political markets.
The gap between qualification (~76%) and passage (~36%) is the entire story of the next six months. Markets believe the campaign moves voters meaningfully against the tax once it begins. That is consistent with Mellman: pre-information support sits at 48-38, falling to 46-44 within the same survey after both sides' arguments are read.
The terminal at /terminal tracks both markets, refreshed every 15 minutes, with timestamps you can verify against Polymarket directly.
What the polls actually say
| Date | Pollster | Yes | No | Und |
|---|---|---|---|---|
| Dec 15, 2025 | Early public poll | 63% | 28% | 9% |
| Jan 12, 2026 | Mellman Group · Pre-information | 48% | 38% | 14% |
| Jan 12, 2026 | Mellman Group · Post-information | 46% | 44% | 10% |
Three polls. Three answers. The early December public poll showed 63-28 in favor, a number that supporters cite and opponents dismiss as the “before anyone had heard the arguments” baseline. The Mellman Group split-sample (n=800, January 2026) tested exactly that: present the headline only and you get 48-38; read the steelmanned counter-arguments and the same respondents move to 46-44. Nine points of swing from a single round of information is the number to watch.
California ballot measures historically lose roughly 10 to 15 points of support between the spring before an election and the November result. If that pattern holds, and Mellman's post-information number is the right starting line, the race ends inside the margin.
The schedule from here
- Oct 22, 2025Initiative filed with the Attorney General
- Dec 26, 2025AG Bonta issues official title and summary
- Jan 14, 2026Building a Better California incorporates as opposition committee
- Feb 18, 2026Campaign kickoff in Los Angeles
- Mar 2, 202625% signature milestone reported
- Apr 27, 2026 · nowSignatures filed at 177% of threshold
- Jun 2, 2026California primary election
- Jun 25, 2026Signature verification deadline
- Aug 15, 2026Ad blitz expected to begin
- Nov 3, 2026General election — Election Day
Who is paying for what
Opposition spending is concentrated in three committees: Building a Better California, Golden State Promise, and the California Business Roundtable's Californians Against Higher Taxes. The funding is dominated by tech founders. Sergey Brin's $58 million single contribution is the largest disclosed California ballot-measure check on file as of this writing.
The donor leaderboard
| Donor | Side | Total |
|---|---|---|
Sergey Brin Google co-founder · NW $272.6B | Opposition | $58M |
Chris Larsen Ripple co-founder | Opposition | $10.5M |
SEIU-UHW Healthcare workers union Mostly in-kind contributions | Proponent | $3.5M |
Eric Schmidt Former Google CEO | Opposition | $3M |
Peter Thiel PayPal co-founder, Founders Fund | Opposition | $3M |
Patrick Collison Stripe co-founder | Opposition | $2M |
John Doerr Kleiner Perkins | Opposition | $2M |
Michael Moritz Sequoia Capital | Opposition | $2M |
Stewart Resnick Wonderful Company | Opposition | $1M |
Five competing measures designed to defeat or dilute
Building a Better California has filed or is preparing five separate ballot measures. In the assessment of California political observers, they are designed either to constrain the wealth tax if it passes or to change what voters are deciding when they get to the booth.
- ◆ Constitutional · RetroactivityProhibit retroactive taxes
Bars the legislature from enacting taxes that apply to income earned before passage.
- ◆ Prop 98 Carve-OutBlock exemptions to education funding minimum
Closes loopholes that would let new taxes bypass the Prop 98 K-12 funding floor.
- ◆ Audit & RefundMandate state audits and excess refunds
Requires the state to audit collected revenue and refund taxpayers when receipts exceed budgeted spending.
- ◆ Housing Decoy$25B middle-class down payment assistance
Bond-funded down payment program — competes for ballot attention and complicates the wealth-tax pitch.
- ◆ CEQA ReformSpeed construction by amending CEQA
Reframes the November agenda toward affordability via supply-side reform rather than redistribution.
The strongest case for and against
The Act's findings argue California faces a compounding crisis: federal Medi-Cal cuts of up to $19 billion annually, $7 billion to $8.6 billion in state cuts to Medi-Cal, federal cuts to SNAP, and education funding pressure on K-14 schools. Closing those gaps requires revenue. The 2026 Billionaire Tax Act's findings cite around 200 California-resident billionaires holding more than $2 trillion in wealth that has grown roughly sevenfold since 2011 ($300B in 2011, $700B in 2019, over $2T in 2025).
The findings, citing Galle, Gamage, and Shanske (113 Cal. L. Rev. 635, 2025) and NBER WP 34170 (Akcan Balkir, Saez, Yagan, Zucman, 2025), argue that California-resident billionaires pay an effective combined tax rate of 24%, against the average taxpayer's 30%. The Act provides for expedited judicial review (Section 37(z)) so that revenue can be deployed without multi-year litigation delay.
A net-worth tax at the state level has no clean precedent in U.S. constitutional law. The U.S. Supreme Court's apportionment clause, the Due Process arguments around taxing unrealized gains, and the practical reality that paper net worth is not the same as available cash all turn this from a single-cycle revenue measure into a multi-decade litigation program. The Act's §50301(c)(2) installment option charges 7.5 percent annually on unpaid balances, which compounds quickly for an asset-rich, cash-poor taxpayer.
California's tax base is already the most volatile of any state. Capital-gains revenue alone has produced budget swings of $20 billion within a single year. Adding a 5 percent one-time hit to the population most able to relocate, at exactly the moment no-income-tax states are courting them, risks accelerating the base erosion the LAO has been warning about since 2018.
How we source and verify
Every figure on this site has a timestamp and a source ID. Donor totals come from California Secretary of State Cal-Access committee filings, refreshed daily. Polymarket prices refresh every 15 minutes via the public Gamma API. Polls are added by hand from published methodology documents. Read the full methodology page for verification rules and source allowlist. Provisions of the Act are quoted from the official AG-filed PDF (25-0024 Amdt. 1).
The result will be in by morning.
Until then, we'll be tracking, and steelmanning both sides, at cbta.davidtphung.com/terminal.