Imposes One-Time Tax on Certain Taxpayers

How it works

1. What kind of measure this is: Proposition 40 is a combined initiative constitutional amendment and statute submitted to the voters under Section 8 of Article II of the California Constitution. It adds a section to the California Constitution and amends and adds sections to the Government Code and the Revenue and Taxation Code, so the voter guide prints the new language in italic type. The voter guide and the Legislative Analyst title it Imposes One-Time Tax on Certain Taxpayers, while the act itself is titled the 2026 Billionaire Tax Act, and the Secretary of State's contribution totals page calls it Imposes One-Time Tax on Certain Individuals and Trusts.^S1S4S7S8S16
2. Path to the ballot: the Institute of Governmental Studies reports that Proposition 40 began as Initiative #25-0024, filed with the California Attorney General's Office on October 22, 2025, that it was cleared for signature gathering on December 26, 2025, that supporters had collected at least 25 percent of the required signatures by February 26, 2026, that they submitted signatures for verification on April 27, 2026, and that the Secretary of State announced it had qualified for the ballot on June 17, 2026. Ballotpedia reports that Service Employees International Union-United Healthcare Workers West is the primary proponent and that the campaign is called Save California Health Care and Public Education.^S14S16
3. The tax itself: 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 or more, and on applicable trusts. Whether a person or trust is applicable is determined as of the tax obligation date, January 1, 2026, and the amount of net worth subject to tax is measured as of the valuation date, December 31, 2026. For purposes of filing returns a married couple is treated as one individual. The tax is 5 percent of net worth. For an individual other than a trust whose net worth is below $1.1 billion, the rate is reduced by 0.1 percentage point, but not below zero, for each $2 million by which the person's net worth falls below $1.1 billion. The Legislative Analyst describes the same structure: billionaires who were California residents on January 1, 2026 would owe a one-time state tax equal to 5 percent of their net worth, due in 2027, with real estate, pensions and retirement accounts generally excluded.^S2S3S7S16
4. Who and what is covered: the tax applies to California residents within the meaning of Revenue and Taxation Code Sections 17014 and 17015.5 as of January 1, 2026, and to applicable trusts. An applicable trust is a trust, other than a grantor trust or tax-exempt trust, that received property from a living individual with net worth of $1 billion or more or from a related entity. A trust may elect to be treated as an applicable trust, and an individual with net worth of $1 billion or more who transferred property to an applicable trust may elect to have the trust treated as part of that individual's net worth. The Legislative Analyst and the League of Women Voters both describe the tax as reaching roughly 200 taxpayers. The findings in the act state that California has around 200 billionaires who collectively hold about $2 trillion in wealth.^S7S2S15S16
5. Paying the tax: any additional tax is reported with, and is due at the same time as, the taxpayer's annual income tax return, so the tax is paid with the 2026 tax filing in 2027. A taxpayer may either pay the amount due with the 2026 income tax or pay annually in five equal installments beginning in the year the tax is due, with each subsequent annual installment also subject to an annual non-deductible deferral charge of 7.5 percent of the remaining unpaid balance. Every California resident individual required to file a return for the 2026 tax year must either declare that their net assets were worth $1 billion or less as of the valuation date or submit a declaration of the additional tax owed with forms, appraisals or other evidence of fair market value. The Franchise Tax Board must promulgate the required forms within six months after passage, and the board must grant six-month filing extensions for tax year 2026 only. The Legislative Analyst notes that taxpayers would have the option to spread the payments over five years but would have to pay more to do so.^S2S3S7S15S16
6. How net worth is computed: genuine debts and other liabilities reduce net worth, with limits. Recourse debts for which the taxpayer is fully personally liable are fully counted; other debts count only up to the value of the collateral; sole proprietorship debts reduce net worth but debts of partnerships, limited liability companies and other business entities do not, except to the extent the taxpayer is personally liable; guarantees of another person's debts do not reduce net worth; and related-party debts, debts contingent on substantially uncertain future events within five years, debts not negotiated at arm's length, and charitable pledges entered into after October 15, 2025 do not reduce net worth. No debt reduces net worth unless market rates of interest are being charged.^S7S16
7. What is counted in net worth: publicly traded assets are valued at market trading value on December 31, 2026; sole proprietorship assets are reported as if directly owned; interests in business entities are valued under a presumption of book value plus a present-value multiplier of 7.5 times average annual book profits, multiplied by the taxpayer's ownership percentage, with a certified appraisal allowed in place of the presumption on clear and convincing evidence that it substantially misstates value; grantor trusts are included; and for other trusts, property transferred by the individual is included, with 75 percent of the value of property transferred in 2025 included. Also included are art, collectibles, intellectual property, vehicles, non-publicly traded financial instruments and debts owed to the taxpayer, subject to a $5 million combined exclusion for those categories; Roth-type retirement accounts above $10 million in present value; property worth more than $1 million transferred for less than fair market value after October 15, 2025; and a dependent's assets above $50,000 in aggregate. An asset's value may not be set below the amount for which it is insured, and a business entity's value may not be set below the valuation in any funding round or equity sale within two years of the valuation date unless the taxpayer shows by clear and convincing evidence that it would significantly overstate value.^S7S16
8. What is not counted: interests in real property held directly by a taxpayer or through a revocable trust are not included in net worth, and qualified pensions and individual retirement arrangements, including those described in Section 219(g)(5) of the Internal Revenue Code and comparable foreign pension arrangements, are exempt from taxation and from the reporting requirements, except that Roth-type accounts above $10 million in aggregate present value are counted. Tangible personal property located outside California for at least 270 days during 2026 is excluded unless it was moved temporarily with a substantial purpose of avoiding tax, and certain nonqualified deferred compensation is exempt unless the taxpayer has a legally binding right to payment. The Legislative Analyst states that real estate, pensions and retirement accounts generally would be excluded, and the League of Women Voters notes that real estate is excluded because it is already subject to property taxes.^S2S3S7S15S16
9. Where the money goes: the act creates the 2026 Billionaire Tax Reserve Fund in the State Treasury. All revenues from the act, including taxes, interest and penalties, less refunds, are deposited to the credit of the Reserve Fund, and after accounting for administrative expenses the Controller allocates the remaining money 90 percent to the Billionaire Tax Health Account and 10 percent to the Billionaire Tax Education and Food Assistance Account. The Legislature may appropriate up to $22,500,000,000 each fiscal year from the health account and up to $2,500,000,000 each year from the education and food assistance account, and may appropriate less if it determines that holding funds in reserve is needed. Health account money is for health care funding, including restoring or addressing reductions in federal funding or state appropriations, protecting or enhancing Medi-Cal and other coverage programs for low and moderate income individuals, supporting safety net providers, preventing facility closures or service reductions, and payments to providers. Education and food assistance money is for kindergarten through grade 14 public education and for programs including CalFresh, CFAP, CalFood and California's universal school meals programs. The Legislative Analyst describes the same split: 90 percent of the money must be spent on health care services for the public, and the rest on education, food assistance and administration of the wealth tax.^S2S3S7
10. Rules meant to stop the money from replacing existing funding: the act states that appropriating money from the Reserve Fund may not be used as justification for reducing, eliminating or failing to increase other state appropriations for health care, education or food assistance, and that the money may not be used to supplant existing state funds for those programs. The Department of Finance must report annually to the Legislature on the Reserve Fund balance, estimated and actual revenue, amounts needed to restore reductions in federal funding and state appropriations, proposed and past expenditures, any recommended reserve, and a certification that Reserve Fund money is not being used to supplant or replace state funding that would otherwise be appropriated. Once the Director of Finance determines that all revenues from the act have been collected and spent, the Legislature may abolish the Reserve Fund. The Director of Finance must transfer up to $50,000,000 to the Franchise Tax Board as a start-up loan from the Reserve Fund or the General Fund for the first year, repaid from taxes collected under the act before any expenditures or appropriations from the Reserve Fund, and the board is reimbursed annually in later years.^S7
11. How the money is treated in the state budget: the act states that the Reserve Fund is a special fund permanently separate from the General Fund and any other state fund, that the taxes and money from the act are not to be considered General Fund revenues, state revenues, moneys or proceeds of taxes under Section 8 of Article XIII B or Sections 8 or 8.5 of Article XVI, that the revenue is not to be considered personal income taxes paid on net capital gains for purposes of Section 20 of Article XVI, and that the taxes are not ad valorem taxes on real property under Section 1 of Article XIII A. Appropriations of revenue from the Reserve Fund are excluded from the appropriations subject to limitation under Article XIII B, and no adjustment to any entity's appropriations limit is required as a result of the revenue. Money in the Reserve Fund may not be borrowed, loaned or transferred to the General Fund or any other state or local fund or account, except as provided in two Government Code sections as they read on January 1, 2025. The Legislative Analyst summarizes this as existing constitutional rules that limit spending and require the state to spend a certain amount on schools and community colleges not applying to this money, and the voter guide summary says the measure exempts such tax revenues from constitutional requirements for school funding, budget reserves and the state spending limit.^{S1S2S3S4S6S7S15S16}
12. Legislative amendment power: the act provides that the Legislature may amend the 2026 Billionaire Tax Act by a statute passed in each house by roll-call vote entered in the journal with two-thirds of the membership concurring, if the statute is consistent with and furthers the purposes of the act. CalMatters reports that the state Constitution allows the Legislature to amend a ballot initiative without another vote when the initiative permits it, that this clause is relatively common, and that courts have upheld amendments that further voters' original goals by any reasonable construction. CalMatters also reports that opponents argue lawmakers could use this power to expand the tax to people with far less than $1 billion, that the measure's purpose and intent section references billionaire wealth three times, that a tax attorney specializing in election law said lawmakers probably could adjust the structure of the tax in marginal ways but probably could not make it more than a one-time tax or lower the wealth threshold, and that because the tax is written into the Constitution, expanding it would likely require another trip to the ballot.^S7S12
13. Severability, expedited review and defending the act: the act's provisions are severable, and a court applying the act must, to the maximum extent consistent with the state and federal constitutions, preserve the tax by reforming dates or periods with the most limited adjustment possible; if the tax obligation date or valuation date is found unconstitutional, those references are to be construed as the earliest dates on which liability may be imposed consistently with law, preserving the 2026 tax year if permissible and otherwise 2027 or the earliest permissible year. A facial challenge may be brought as a validation action without the taxpayer having to pay the tax first, must be filed within 60 days after voter approval, is heard only in Sacramento County Superior Court with any appeal going directly to the California Supreme Court, and the courts are to make every effort to resolve the trial by April 1, 2027 and any review by November 1, 2027. The state, government agencies and officials, other government employers, the proponent, or in the absence of a proponent any citizen of the state may defend the act, and reasonable fees and costs of defending it are a charge on funds appropriated to the Attorney General if the Attorney General does not defend it. The act also includes enforcement provisions, including penalties of 20 percent of an understatement for a substantial understatement and 40 percent for a gross understatement, and a general anti-avoidance rule letting the Franchise Tax Board deny tax benefits for transactions lacking economic substance.^S7
14. What happens if Proposition 41 or 42 gets more votes: the Legislative Analyst's analysis of Proposition 40 includes a section titled Potential Interactions With Other Propositions. It states that if Proposition 41 or 42 on the same ballot receives more yes votes than Proposition 40, then Proposition 40 could be stopped from becoming law even if it gets yes votes from a majority of voters, because the courts could find that Proposition 41 or 42 conflicts with Proposition 40. Proposition 40's own conflicts section states that a measure on the same statewide ballot that levies a tax on or affects tax rates on the net worth of billionaires, or that provides for use of funds from a tax on billionaire net worth, is deemed to be in conflict with Proposition 40, and that if Proposition 40 receives a greater number of affirmative votes than a conflicting measure, Proposition 40 prevails in its entirety and the conflicting provisions are null and void. Ballotpedia reports that Propositions 41 and 42 each contain competing measure provisions that would nullify Proposition 40 if all are approved but 41 or 42 receives more votes, and that Proposition 40 also contains a provision that would nullify Propositions 41 and 42 if Proposition 40 receives more votes. CalMatters reports the same: if Proposition 40 captures more votes than both 41 and 42, the wealth tax takes effect and voids the countermeasures, and if either 41 or 42 out polls Proposition 40, the billionaire tax does not take effect.^{S3S7S10S13S16}
15. Background the Legislative Analyst gives for the measure: California is home to a few hundred people with net worth over $1 billion, often called billionaires, and many of them gained their wealth as executives or investors in California technology companies. The state and federal government spend over $200 billion per year on state health care programs, most of it for Medi-Cal, the state's health insurance program for low income people, and state spending also supports public health programs, mental health care, and drug and alcohol treatment. The findings printed in the act state that Medi-Cal covers nearly 15 million low income Californians, including more than half of the state's children, 2.2 million seniors and people with disabilities and one in five working adults; that Medi-Cal is projected to lose up to $19 billion in annual federal funding under the most recent federal budget legislation and administrative action, with federal cuts to Medi-Cal alone projected to total approximately $190 billion over ten years; and that state cuts to Medi-Cal are estimated to reach $7 billion in 2027-28 and $8.6 billion each year from 2028-29 onward. CalMatters reports that state officials project the federal cuts could amount to $30 billion a year, and the League of Women Voters reports that California is expected to lose about $30 billion annually in Medi-Cal funding when the federal law is fully implemented on January 1, 2027, while also facing up to $9.5 billion in new administrative costs. These figures are the findings and projections stated in the act and reported by the cited sources.^S2S3S7S11S15
16. How California taxes wealth today, as background: the League of Women Voters states that California, like the rest of the United States, has traditionally taxed income rather than wealth, that income is money people earn over time while wealth is the total value of what a person owns minus debts, and that California already taxes certain forms of wealth through property taxes on homes and commercial real estate, which apply to specific property rather than a person's total net worth. The findings in the act make a similar point, citing the annual Vehicle License Fee, a tax based on 0.65 percent of the value of a vehicle, and the annual property tax on housing of about 1 percent of assessed value as examples of narrower wealth taxes already paid by Californians. The act's findings also cite economic research stating that California billionaires pay 24 percent of their income in taxes at all levels of government while the average taxpayer pays 30 percent, and the findings quote research reporting that California billionaires' wealth grew an average of over 15 percent per year from 2019 to 2025 while they paid on average about 0.26 percent of their wealth annually in state income taxes.^S7S15
17. What the measure does not do: CalMatters reports that if a person is not a billionaire the tax does not apply, and that even for billionaires the measure exempts pensions and individual retirement accounts, with the most notable exception being Roth IRAs containing more than $10 million. CalMatters also reports that there are no active proposals to tax middle class retirement accounts on the ballot or in the Legislature. The measure does not create a tax on income, wages, sales, real property, or home equity, and the Legislative Analyst states the costs to administer the wealth tax would be paid from the new wealth tax revenues rather than from a new tax.^S2S3S11S16

Fiscal impact

The Legislative Analyst's summary of the estimate of net state and local government fiscal impact is a temporary state revenue increase from a new wealth tax on billionaires, with those wealth tax revenues probably adding up to tens of billions of dollars spread over several years, and a possible ongoing decrease of less than $1 billion per year in state income tax revenue collected from billionaires.

The analysis states the state probably would collect tens of billions of dollars from the wealth tax, that the temporary increase in state tax collections would be spread across several years, and that exactly when and how much the state would collect is very hard to predict because it is hard to know what actions billionaires would take to reduce the amount of tax they pay and because much of the wealth is based on stock prices, which are always changing.

On the revenue side it states that California billionaires currently pay state taxes on their annual income, that they may respond to a new wealth tax in ways that reduce their income tax payments, for example by deciding to leave California, that the income taxes they currently pay would also go away, and that these responses probably would reduce state revenues by less than $1 billion per year, which could mean less money for the General Fund, the account that pays for most public services including education, health care and prisons.

On costs it states the state would have costs to determine how much wealth tax is owed and to collect payments, that these costs could be tens of millions of dollars per year for several years, and that these costs would be paid from the new wealth tax revenues. The Institute of Governmental Studies summarizes the same estimate: tens of billions of dollars in temporary state revenue over several years with the actual amount uncertain because of changing asset values and actions billionaires might take, a possible reduction in ongoing state income tax revenue of less than $1 billion annually, and administration and collection costs of tens of millions of dollars each year for several years paid from the new tax revenue.

The League of Women Voters states the same three effects. The act itself directs the Franchise Tax Board to be reimbursed from the Reserve Fund for actual and necessary costs of administering the act, after a start-up loan of up to $50 million that is repaid from taxes collected before any expenditures or appropriations are made.

The measure also sets annual appropriation ceilings from the two new accounts of $22,500,000,000 for health care and $2,500,000,000 for education and food assistance.^{S1S2S3S4S6S7S14S15S16}

How it could affect your household

Tradeoffs

• Temporary money for an ongoing problem: supporters say the measure would raise about $100 billion to replace federal health care cuts and protect services without raising taxes on the middle class, small businesses or homeowners, and the act's findings say California billionaires' wealth would only modestly slow and that even after paying the tax they will continue to amass ever rising fortunes. The argument against says the measure is a one-time tax that provides only temporary funds and that when the money runs out politicians will be back with another tax, and the League of Women Voters reports opponents saying it will not be temporary because it tries to solve a problem that is permanent as federal funding continues to fall short of the state's health care spending. The Legislative Analyst's own estimate is a temporary revenue increase spread over several years, which is the point both sides are arguing about.^{S2S3S5S6S7S15}
• Dedicated revenue against a guarantee that it replaces cuts: 90 percent of the revenue must go to health care, and the act states that appropriating Reserve Fund money may not justify reducing, eliminating or failing to increase other state appropriations for health care, education or food assistance and that the money may not supplant existing state funds. The California Medical Association and Planned Parenthood circulated a memo reported by CalMatters arguing there is no guarantee the money would replace the federal funding cuts because the proposition also allows the money to offset state cuts to Medi-Cal, which they say would let lawmakers use the new money to hold state funding levels and free up the General Fund for other things. CalMatters reports that similar special funds have been used to replace existing funding in the past, and that supporters say the concern does not make sense because the measure was written to create funding for a shortfall rather than to close one.^S7S11
• Exempting the revenue from the school funding guarantee and the spending limit: the act provides that Reserve Fund revenue is not General Fund revenue or proceeds of taxes for the state spending limit, that appropriations of it are excluded from the appropriations subject to limitation, and that it does not count toward the Proposition 98 minimum funding guarantee for schools and community colleges. Supporters present this as letting the money be spent without unnecessary delay. The argument against says the measure exempts itself from voter approved constitutional protections for schools and shortchanges public schools $3 billion annually, and that it exempts itself from the state spending limit including its requirement that excess revenues be returned to taxpayers. The voter guide summary and the Legislative Analyst both state the measure exempts the revenue from the constitutional requirements for school funding, budget reserves and the state spending limit, so the exemption itself is not in dispute; what is disputed is how much money schools and taxpayers lose as a result.^{S1S2S3S4S5S6S7}
• Taxing wealth that has not been sold against the difficulty of valuing it: the act taxes a 5 percent share of net worth measured as of December 31, 2026, including publicly traded securities at market value, business interests, art, collectibles, intellectual property, vehicles and non-publicly traded financial instruments, and it excludes directly held real property and qualified pensions and retirement arrangements. CalMatters reports that the state is not in the business of valuing and taxing personal property, that the measure would require the state within six months to create a way to assess a wide range of holdings, that a UCLA tax law professor said the definition of wealth has to be broad to close workarounds, that a former Franchise Tax Board attorney said the board has no way of knowing anyone's net wealth, and that a USC tax policy professor said stocks are easily valued and the state could look to the federal estate tax for art and jewelry. The act addresses valuation with presumptions, certified appraisals, minimum valuation floors and anti-avoidance rules, and the Legislative Analyst states exactly when and how much the state would collect is very hard to predict.^S2S3S7S11
• Retroactive application against tax flight and legal challenge: the tax applies to individuals who were California residents on January 1, 2026, which had already passed when the measure qualified for the ballot, so people who left the state afterward would still owe it. CalMatters reports that a San Francisco tax attorney expects clients to sue over the measure's retroactive nature, citing 1920s U.S. Supreme Court decisions on the federal estate and gift taxes and a 1994 decision that retroactive taxes can be constitutional in limited circumstances, and that he called the argument reasonable but said taking advantage of it would require leaving the state. CalMatters also reports that Hoover Institution researchers estimate billionaires representing 30 percent of the tax base have publicly said they have left, lowering state revenue estimates by $60 billion, while the Legislative Analyst estimates the revenue decrease at less than $1 billion per year. The act provides for an expedited validation action in Sacramento County Superior Court with direct appeal to the California Supreme Court.^S2S3S7S11S13
• Legislative power to amend against voter control: the act lets the Legislature amend it by a two thirds roll call vote if the change is consistent with and furthers its purposes. The argument against and the opposition campaign say this gives politicians power to expand the tax beyond billionaires to savings, retirement accounts and home equity. CalMatters reports that the claim is only partially true: the state Constitution permits legislative amendment of an initiative when the initiative allows it, courts have upheld amendments that further voters' goals by any reasonable construction, an election law attorney said lawmakers probably could adjust the structure of the tax in marginal ways but probably could not make it more than a one-time tax or lower the wealth threshold, and because the tax is written into the Constitution, expanding it would likely require another trip to the ballot. The act's purpose and intent section references a one-time tax on billionaire wealth three times, and the voter guide arguments target approximately 200 California billionaires.^S5S6S7S12S19
• A majority yes vote might not be enough: the Legislative Analyst states that if Proposition 41 or 42 receives more yes votes than Proposition 40, Proposition 40 could be stopped from becoming law even if it gets yes votes from a majority of voters, because the courts could find that Proposition 41 or 42 conflicts with Proposition 40. Proposition 40's own conflicts section says it prevails in its entirety if it receives more affirmative votes than a conflicting measure on the same ballot, and Propositions 41 and 42 contain competing measure provisions pointing the other way. CalMatters reports that if Proposition 40 captures more votes than both 41 and 42 the wealth tax takes effect and voids the countermeasures, and that if either 41 or 42 out polls Proposition 40 the billionaire tax does not take effect. CalMatters also reports that polling shows slim majorities of likely voters supporting all three measures and that the polling director of the Public Policy Institute of California said he does not think people realize yet that 41 and 42 are direct countermeasures.^{S3S7S10S13S16}
• Money on both sides, as reported by sources that measure different things: the Secretary of State's compiled totals through 10/06/2026 report $32,213,823 in contributions to the two committees formed to support the measure and $99,596,279 to the four committees formed to oppose it. The Fair Political Practices Commission's top 10 contributors list for the November 2026 general election reports $32,346,200.51 in top aggregated contributions in support and, across the two opposing committees it lists, $114,171,279.44 in top aggregated contributions in opposition. Ballotpedia reports $32,202,655.53 in total support contributions and $101,728,053.58 in total opposition contributions through September 19, 2026, counting five opposition committees including Building a Better California, which also contributed to campaigns on other measures. CalMatters reported that the opposition had raised more than $205 million and that Sergey Brin had spent more than $138 million counting his spending on Propositions 41 and 42. The largest reported donors are SEIU-UHW at $22,058,461.16 in support and, in opposition, Building a Better California at $103,500,000, Sergey Brin at $102,000,000 and L. John Doerr, III at $30,000,000.^{S8S9S11S13S16}
• What the vote decides and what it leaves open: the measure fixes the 5 percent one-time tax and the residency date, the exclusion of directly held real property and qualified pensions and retirement arrangements, the 90/10 split of revenue, the annual appropriation ceilings of $22.5 billion and $2.5 billion, the treatment of the Reserve Fund as separate from the General Fund and outside the spending limit and the school funding guarantee, the two thirds legislative amendment power, and the expedited review process. It leaves to the Legislature the annual appropriation decisions from the two accounts, the implementing statutes and the Franchise Tax Board's regulations, the design of the forms and the appraisal process, and the Board's determinations about which receivables and similar assets are taxable. The Legislative Analyst states that the state would decide how and when to spend the money from the wealth tax as long as it is spent on the required types of services, and that the exact amount collected is very hard to predict.^S2S3S7
• Polling, reported as polling: Ballotpedia's table of 2026 polls on the measure records a Public Policy Institute of California poll of 1,103 likely voters conducted September 4 to 10, 2026 with support at 52 percent, opposition at 46 percent and 2 percent undecided; a Survey USA poll of 742 likely voters conducted September 15 to 20, 2026 with support at 48 percent, opposition at 40 percent and 12 percent undecided; a Politico poll of 1,983 likely voters conducted September 8 to 14, 2026 with support at 45 percent, opposition at 43 percent and 12 percent undecided; and a UC Berkeley Institute of Governmental Studies poll of 2,310 likely voters conducted August 3 to 9, 2026 with support at 48 percent, opposition at 41 percent and 11 percent undecided. CalMatters reports that recent polling shows slim majorities of likely voters support Proposition 40 and also Propositions 41 and 42. These are reported poll results, not predictions of the outcome.^S13S16

Sources

1. Proposition 40 Official Title and Summary (Official Voter Information Guide, November 3, 2026) California Secretary of State Accessed 2026-10-17
2. Proposition 40 Analysis by the Legislative Analyst (Official Voter Information Guide, November 3, 2026) California Secretary of State and Legislative Analyst's Office Accessed 2026-10-17
3. Proposition 40 [Ballot], Propositions on the November 3, 2026 Ballot Legislative Analyst's Office Accessed 2026-10-17
4. Proposition 40 summary page (Official Voter Information Guide, November 3, 2026) California Secretary of State Accessed 2026-10-17
5. Proposition 40 Arguments and Rebuttals (Official Voter Information Guide, November 3, 2026) California Secretary of State Accessed 2026-10-17
6. Proposition 40 print version, Official Voter Information Guide (title and summary, analysis by the Legislative Analyst, argument in favor, rebuttal, argument against, rebuttal) California Secretary of State Accessed 2026-10-17
7. Proposition 40 Text of Proposed Laws, Official Voter Information Guide (new Section 37 added to Article XIII of the California Constitution, and the 2026 Billionaire Tax Act added to the Government Code and the Revenue and Taxation Code) California Secretary of State Accessed 2026-10-17
8. Proposition 40 – Imposes One-Time Tax on Certain Individuals and Trusts. Initiative Constitutional Amendment and Statute., 2026 Ballot Measure Contribution Totals California Secretary of State (Cal-Access) Accessed 2026-10-17
9. Top 10 Contributors List, November 2026 General Election California Fair Political Practices Commission Accessed 2026-10-17
10. CalMatters California Voter Guide 2026: Proposition 40, Apply one-time tax to billionaires to fund healthcare and education CalMatters Accessed 2026-10-17
11. Billionaire tax explained: What you need to know about Prop. 40 (Jeanne Kuang and Kristen Hwang, October 1, 2026) CalMatters Accessed 2026-10-17
12. Fact check: Could California lawmakers expand the billionaire tax to everyone? (Kristen Hwang, October 2, 2026) CalMatters Accessed 2026-10-17
13. The billionaire tax could be defeated by two other tax measures. Here's how (Kristen Hwang, published September 24, 2026, updated September 28, 2026) CalMatters Accessed 2026-10-17
14. Proposition 40: One-Time Wealth Tax, California Ballot Proposition Guides, November 3, 2026 General Election Institute of Governmental Studies, University of California, Berkeley Accessed 2026-10-17
15. Prop 40 (2026), The 2026 Billionaire Tax Act, CaVotes ballot measure guide League of Women Voters of California Education Fund Accessed 2026-10-17
16. California Proposition 40, One-Time Wealth Tax for State-Funded Healthcare, Education, and Food Assistance Programs Initiative (2026) Ballotpedia Accessed 2026-10-17
17. Quick Reference Guide – Proposition 40 (Official Voter Information Guide, November 3, 2026) California Secretary of State Accessed 2026-10-17
18. Yes on 40, campaign website of the committee supporting the measure Yes on 40 – Billionaire Tax Now, sponsored by Service Employees International Union – United Healthcare Workers West Accessed 2026-10-17
19. Californians Against Tax Increases, Sponsored by the California Business Roundtable – No on 40, campaign website of the committee opposing the measure Californians Against Tax Increases, Sponsored by the California Business Roundtable – No on 40 Accessed 2026-10-17