SAVE LIVES. TAX BILLIONAIRES.

Can Billionaires Pay if Their Wealth Is in Stocks or a Business?

Wealth held in stocks or a business is still wealth. Prop 40 includes valuation, installment, and qualifying deferral rules so the question is how to collect the contribution—not whether only cash can ever be taxed. [1]

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Yes on 40Evidence checked September 10, 2026Campaign/legal review draft

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Vote Yes on Prop 40. Read the actual payment options before accepting the claim that valuable ownership makes a billionaire unable to contribute.

The facts at a glance

Publicly traded assets and private-business interests have different valuation provisions. [1]

Specified private-business presumptions can be rebutted using evidence and a certified appraisal. [1]

The statute does not require billionaire taxpayers to liquidate all holdings immediately. [1]

“Not cash” does not mean “no value”

The measure uses fair market value as its general standard and gives specific rules for different assets. A publicly traded share can have a market price even if its owner has not sold it. A nonpublic ownership interest may need a different valuation method. [1]

The relevant questions are the value of the covered asset and how the taxpayer can pay—not whether the asset was already sitting in a bank account. Mixing those questions makes the proposal sound less specific than it is.

Publicly traded stocks use the public-market rule

Section 50303(c)(1) governs publicly traded assets. The default valuation is based on market prices at the valuation date. A separate private-business presumption should not be substituted for that rule when describing a person’s public stock holdings. [1]

The Galle–Gamage–Saez–Shanske memo on controlling shares addresses this distinction directly. It explains the authors’ interpretation of the relevant provisions, including the difference between voting control and the value of the covered interest. It is cited as a drafters’ explanation, with the actual statutory language linked beside it. [2]

Private interests have an evidence-based rebuttal route

For the nonpublic business interests covered by section 50303(c)(3), the statute supplies presumptions based on ownership and business information. It also permits a taxpayer or the board to show, with clear and convincing evidence, that specified presumptions substantially overstate or understate the value or percentage owned, and use a certified appraisal instead. [1]

That does not mean a taxpayer can choose any lower number. It means the proposal includes a mechanism for documented valuation disputes. The existence of a presumption is not the same as an irrebuttable assessment. [1]

Payment can be spread out

The standard option is five equal annual installments of principal, with interest accruing on deferred or unpaid balances. A separate optional deferral account is available under specified conditions for taxpayers whose liability exceeds the relevant publicly traded assets. [1]

Neither option guarantees that no owner ever sells an asset. Both are directly relevant when someone claims that the measure demands an immediate all-or-nothing liquidation of assets. The statute does not impose that universal requirement. [1]

The same system includes enforcement

The Franchise Tax Board has examination duties, and the measure includes appraisal, administration, and penalty provisions. Its rules also address trusts and debts so that covered wealth is not defined simply by whatever number a taxpayer chooses to report. [1]

The policy choice is whether billionaire wealth should contribute to essential care under a defined set of rules. Our answer is Yes. Technical details should help explain that choice—not obscure the fact that the proposal has valuation and payment mechanisms at all.

A few more answers

Does voting control always equal the value used for every company?

No. Publicly traded assets have their own rule; specified nonpublic-business presumptions have an appraisal-based rebuttal path. The exact asset and provision matter. [1]

Can I assume every deferral application will be approved?

No. The optional deferral account has eligibility requirements and operates through the statutory agreement and reporting structure. [1]

The people and institutions behind the evidence

Measure drafter and legal-analysis author

Brian Galle

The July 2026 explanatory report identifies Brian Galle with UC Berkeley. A measure drafter and coauthor of the legal analysis, he also explains the proposal in a Berkeley Law interview. [3] [4] [5]

Measure drafter and legal-analysis author

David Gamage

The July 2026 explanatory report identifies David Gamage with the University of Missouri. He is a measure drafter and coauthor of the legal and valuation analyses. [2] [3] [4]

Working-paper author and disclosed unpaid design/scoring adviser

Emmanuel Saez

The July 2026 explanatory report identifies Emmanuel Saez with UC Berkeley. He coauthored the revenue paper and discloses unpaid design/scoring advice. [3] [6]

Measure drafter and legal-analysis author

Darien Shanske

The July 2026 explanatory report identifies Darien Shanske with UC Davis. He is a measure drafter and coauthor of the legal and valuation analyses. [2] [3] [4]

Tax administration and residency guidance; not a campaign endorser

California Franchise Tax Board

The measure assigns collection and examination duties to the FTB. Its residency guidance explains existing concepts. [1] [7]

Read the relevant source →

Keep reading

CHECK THE EVIDENCE

Sources behind this page

Each reference identifies what it establishes. A cited agency or researcher is not automatically a campaign endorser.

01Proposition 40: text of proposed laws

California Secretary of State · 2026 voter guide · Proposed law

The actual proposed rules on taxpayer eligibility, valuation, payments, spending, and reporting. Tax payments begin in 2027; audit authority and special trust rules remain. Section 50310 governs possible amendments.

Where to look: Gov. Code §16355, PDF pp. 4–5; Rev. & Tax. Code §§50301, 50303–50304, 50308–50312, PDF pp. 5–13.

https://vig.cdn.sos.ca.gov/2026/general/pdf/prop40-text-proposed-laws.pdf

03The California Billionaire Tax: an expert report

Brian Galle, David Gamage, Emmanuel Saez, and Darien Shanske · Updated July 20, 2026 · Proponent expert report

The proposal’s drafters explain its funding estimates, payment installments, and qualifying deferral arrangements.

Where to look:

https://eml.berkeley.edu/~saez/galle-gamage-saez-shanskeCAbillionairetaxJuly26.pdf

05Professor Brian Galle on “How to Tax the Ultrarich”

Berkeley Law Voices Carry; host Gwyneth Shaw · February 17, 2026 · Interview with full transcript

A Berkeley Law interview with a full transcript about taxing the ultrarich. Galle distinguishes federal reform from the California proposal he helped draft.

Where to look:

https://www.law.berkeley.edu/podcast-episode/professor-brian-galle-how-to-tax-the-ultrarich-voices-carry/

06California Billionaires: Wealth, Taxes, and Wealth Tax Revenue Estimates

Jasper Boll, Emmanuel Saez, and Gabriel Zucman · 2026 working paper; author-hosted version checked September 10, 2026 · Working paper

Working-paper estimate, not observed collections or an institutional NBER endorsement. Saez discloses unpaid design/scoring advice. The downloaded version has differing cover/abstract revision labels; no single revision date is asserted.

Where to look: Abstract and disclosure, PDF pp. 1–2.

https://eml.berkeley.edu/~saez/BSZ26CAbillionaires.pdf

07Residency status: California tax guidance

California Franchise Tax Board · Undated; checked September 10, 2026 · Official tax guidance

Distinguishes residence, domicile, and temporary or transitory absence. No individual taxpayer status is determined here.

Where to look: Resident and nonresident definitions

https://www.ftb.ca.gov/file/personal/residency-status/index.html

About this page. Published as a review draft by the Yes on 40 campaign, which advocates passage of the measure. Sources were checked on September 10, 2026. Research estimates, proposed legal provisions and endorsements are identified separately. This page is not individual tax or legal advice. Send corrections with the relevant source to the campaign’s press contact.

Vote Yes on Prop 40.

Vote Yes on Prop 40. Just because vast wealth is held in ownership interests and not cash is not a reason to abandon the people who need healthcare.

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