# Billionaire one-time wealth tax passes in California election 2026?

Updated: August 6, 2026

Category: Politics

Tags: Taxes, referendum, referendums midterms, Fiscal, Elections

HTML: /markets/politics/taxes/billionaire-one-time-wealth-tax-passes-in-california-election-2026/

## Short Answer

**Key takeaway.** Both the **model** and the **market** expect a billionaire one-time wealth tax to pass in the California 2026 election, with no compelling evidence of mispricing.

## Key Claims (January 2026)

**- - Yes appears supported by recent public polling showing majority voter sentiment.** - Yes likely faces opposition from major business groups, impacting its prospects.
- Yes is challenged by historical low success rates for similar tax initiatives.

### Why This Matters (GEO)

- AI agents extract claims, not arguments.
- Improves citation probability in summaries and answer cards.
- Enables fact stitching across multiple sources.

## Executive Verdict

**Key takeaway.** At 30c, **market** prices higher than the **26.8%** **model** estimate, despite state leader opposition.

### Who Wins and Why

| Outcome | Market | Model | Why |
| --- | --- | --- | --- |
| Yes | 30.0% | 26.8% | California voters may favor policies addressing wealth inequality and state revenue needs. |

## Model vs Market

- Model Probability: 26.8% (Yes)
- Market Probability: 30.0% (Yes)
- Yes refers to: Yes
- Edge: -3.2pp
- Expected Return: -10.8%
- R-Score: -0.32
- Total Volume: $3,617,972.37
- 24h Volume: $109.73
- Open Interest: $0

- Expiration: November 3, 2026

## Market Behavior & Price Dynamics

The prediction market for a 2026 California one-time wealth tax has traded in a narrow, sideways range with a slight downward drift. The market opened pricing the initiative's passage at a 34.5% probability. It subsequently fell to 30.5%, where it has remained. This price action occurred after the measure, Proposition 40, officially qualified for the November 2026 general election ballot on June 17.

Market conviction is nonexistent. Total traded volume is zero, indicating that the price movement reflects automated adjustments rather than any trader activity. Without traded volume, conventional support and resistance levels are not established. The price range of 29.5% to 34.5% represents the bounds of the initial pricing mechanism. The current 30.5% price suggests sentiment is skeptical of the measure's passage, but this reading is entirely untested by market participants.

## Contract Snapshot

Here are the contract rules for this market:

1.  **YES resolution**: The market resolves to "Yes" if any statewide California proposition imposing a one-time tax on individuals, households, or family units with at least $1 billion (USD or equivalent) in wealth, assets, or net worth passes in the November 3, 2026 general election.
2.  **NO resolution**: The market resolves to "No" if no such qualifying proposition passes. It will also resolve "No" if no qualifying ballot initiative is certified by the deadline, or if all qualifying propositions are removed or amended before the election such that the main threshold drops below $1 billion.
3.  **Key dates/deadlines**: The relevant election is November 3, 2026. A critical deadline for a qualifying ballot initiative to be certified is June 25, 2026, 11:59 PM ET.
4.  **Special settlement conditions**: The market will primarily use official information from the Government of the State of California for resolution. A consensus of credible reporting may also be used for settlement.

## Market Discussion

Traders in this market generally anticipate that California's Proposition 40, a one-time billionaire wealth tax, will not pass in the 2026 election, reflected in its current 31% chance of success. Key arguments against its passage include strong opposition from Governor Newsom and other Democratic leaders, concerns about out-migration of high-net-worth residents, and competing "poison pill" initiatives designed to nullify the tax. Although earlier polling showed narrow support and one participant suggested the tax is "underpriced" due to potential voter irrationality, these points are largely overshadowed by the stated consensus favoring rejection.

## Market Data

| Contract | Yes Bid | Yes Ask | Last Price | Volume | Open Interest |
| --- | --- | --- | --- | --- | --- |
| Yes | 30% | 31% | 30% | $3,617,972.37 | $0 |

## How does the campaign messaging and funding for Proposition 40 compare to its competing measures, Propositions 41 and 42, ahead of the November 2026 election?

Prop 40 Tax Rate | One-time 5% tax on assets over $1 billion [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html)[[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://ballotpedia.org/California_Proposition_40,_One-Time_Wealth_Tax_for_State-Funded_Healthcare,_Education,_and_Food_Assistance_Programs_Initiative_(2026)) |
Prop 40 Backer | SEIU United Health Workers West [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html)[[^]](https://calmatters.org/politics/2026/08/billionaire-tax-california-democrats-split/) |
Prop 41/42 Funding Source | 'Building a Better California,' funded by wealthy individuals including Sergey Brin [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html)[[^]](https://calmatters.org/politics/2026/08/billionaire-tax-california-democrats-split/)[[^]](https://ballotpedia.org/California_Proposition_40,_One-Time_Wealth_Tax_for_State-Funded_Healthcare,_Education,_and_Food_Assistance_Programs_Initiative_(2026))[[^]](https://ballotpedia.org/California_Proposition_41,_Prohibit_Excluding_New_State_Taxes_from_Spending_Limit_and_Require_Special_Tax_Audits_Initiative_(2026))[[^]](https://ballotpedia.org/California_Proposition_42,_Prohibit_New_Taxes_on_Retirement_Holdings,_Personal_Assets,_and_Savings_and_Limit_Retroactive_Taxes_Initiative_(2026))[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/) |

**Proposition 40 proposes a wealth tax to fund social programs**

Proposition 40 proposes a wealth tax to fund social programs. This citizen-initiated ballot measure aims to levy a one-time **5%** tax on California residents possessing over **$1** billion in assets [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html)[[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://ballotpedia.org/California_Proposition_40,_One-Time_Wealth_Tax_for_State-Funded_Healthcare,_Education,_and_Food_Assistance_Programs_Initiative_(2026)). The revenue generated from this tax is earmarked to support critical healthcare, food assistance, and education initiatives [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html)[[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://ballotpedia.org/California_Proposition_40,_One-Time_Wealth_Tax_for_State-Funded_Healthcare,_Education,_and_Food_Assistance_Programs_Initiative_(2026))[[^]](https://ballotpedia.org/California_2026_ballot_propositions). Notably, the labor union SEIU United Health Workers West is a primary backer of Proposition 40 [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html)[[^]](https://calmatters.org/politics/2026/08/billionaire-tax-california-democrats-split/).

Competing measures 41 and 42 aim to nullify new wealth taxes. Propositions 41 and 42 directly oppose Proposition 40, designed either to undercut or entirely invalidate its tax provisions [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html)[[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://ballotpedia.org/California_Proposition_40,_One-Time_Wealth_Tax_for_State-Funded_Healthcare,_Education,_and_Food_Assistance_Programs_Initiative_(2026)). Proposition 41 specifically suggests implementing constitutional amendments that would require state audits for new special taxes enacted after January 1, 2026 [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html)[[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://ballotpedia.org/California_Proposition_41,_Prohibit_Excluding_New_State_Taxes_from_Spending_Limit_and_Require_Special_Tax_Audits_Initiative_(2026))[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/). Meanwhile, Proposition 42 seeks to establish constitutional amendments prohibiting new taxes on retirement holdings and personal assets, alongside restricting retroactive taxation [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html)[[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://ballotpedia.org/California_Proposition_42,_Prohibit_New_Taxes_on_Retirement_Holdings,_Personal_Assets,_and_Savings_and_Limit_Retroactive_Taxes_Initiative_(2026))[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/). Both Propositions 41 and 42 receive significant financial backing from wealthy individuals, including Google co-founder Sergey Brin, channeled through the committee 'Building a Better California,' underscoring strong opposition to the proposed billionaire tax [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html)[[^]](https://calmatters.org/politics/2026/08/billionaire-tax-california-democrats-split/)[[^]](https://ballotpedia.org/California_Proposition_40,_One-Time_Wealth_Tax_for_State-Funded_Healthcare,_Education,_and_Food_Assistance_Programs_Initiative_(2026))[[^]](https://ballotpedia.org/California_Proposition_41,_Prohibit_Excluding_New_State_Taxes_from_Spending_Limit_and_Require_Special_Tax_Audits_Initiative_(2026))[[^]](https://ballotpedia.org/California_Proposition_42,_Prohibit_New_Taxes_on_Retirement_Holdings,_Personal_Assets,_and_Savings_and_Limit_Retroactive_Taxes_Initiative_(2026))[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/).

All three propositions qualified with a unique 'poison pill' feature. By June 2026, all three measures successfully qualified for the November 3, 2026, general election ballot [[^]](https://news.ballotpedia.org/2026/06/24/california-billionaires-tax-qualifies-for-the-nov-3-ballot/)[[^]](https://news.ballotpedia.org/2026/06/18/california-billionaires-tax-qualifies-for-the-november-ballot-competing-measures-pending-signature-verification/)[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/). A crucial element across these propositions is the inclusion of "poison pill" provisions, which dictate that should multiple measures pass, the one securing the highest number of votes will take precedence, potentially nullifying the others [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/).

## What is the historical success rate of progressive tax ballot initiatives in California over the past decade, and how do their campaigns compare to the current effort for Proposition 40?

Citizen-initiated measure success rate | 36% (since 1910) [[^]](https://ballotpedia.org/How_many_initiatives_have_there_been_in_California)[[^]](https://news.ballotpedia.org/2025/01/06/californians-decided-on-1306-ballot-measures-between-1910-and-2024/)[[^]](https://news.ballotpedia.org/2025/01/09/a-comprehensive-look-at-all-ballot-measures-in-california-from-1910-2024/) |
Legislatively referred measure success rate | 69% [[^]](https://ballotpedia.org/How_many_initiatives_have_there_been_in_California)[[^]](https://news.ballotpedia.org/2025/01/06/californians-decided-on-1306-ballot-measures-between-1910-and-2024/)[[^]](https://news.ballotpedia.org/2025/01/09/a-comprehensive-look-at-all-ballot-measures-in-california-from-1910-2024/) |
Proposition 40 proposed wealth tax | 5% (one-time on >$1 billion net worth) [[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://lao.ca.gov/BallotAnalysis/Proposition?number=40&year=2026)[[^]](https://www.sos.ca.gov/administration/news-releases-and-advisories/2026-news-releases-and-advisories/california-secretary-state-shirley-n-weber-phd-announces-new-measure-eligible-november-2026-general-election-ballot-imposes-one)[[^]](https://apnews.com/article/california-billionaire-tax-ballot-healthcare-measure-9edd9fb1cb2e7f0717b5b1b620fd0e05) |

**California citizen-initiated tax measures historically have a low success rate**

California citizen-initiated tax measures historically have a low success rate. Since 1910, approximately **36%** of citizen-initiated ballot measures have been approved by voters, a notable contrast to the **69%** success rate for legislatively referred measures [[^]](https://ballotpedia.org/How_many_initiatives_have_there_been_in_California)[[^]](https://news.ballotpedia.org/2025/01/06/californians-decided-on-1306-ballot-measures-between-1910-and-2024/)[[^]](https://news.ballotpedia.org/2025/01/09/a-comprehensive-look-at-all-ballot-measures-in-california-from-1910-2024/). Taxes frequently appear as subjects for California ballot measures [[^]](https://news.ballotpedia.org/2025/01/09/a-comprehensive-look-at-all-ballot-measures-in-california-from-1910-2024/)[[^]](https://news.ballotpedia.org/2025/01/06/californians-decided-on-1306-ballot-measures-between-1910-and-2024/). While specific success rates for progressive tax initiatives over the past decade are not detailed in the research, California voters did reject Proposition 30, a progressive tax initiative, in 2022 [[^]](https://ballotpedia.org/California_2022_ballot_propositions).

Proposition 40, a wealth tax, faces significant opposition and complex challenges. This citizen-initiated measure, set for the November 2026 ballot, proposes a one-time **5%** wealth tax on California residents with over **$1** billion in net worth, intended to fund healthcare, education, and food assistance [[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://lao.ca.gov/BallotAnalysis/Proposition?number=40&year=2026)[[^]](https://www.sos.ca.gov/administration/news-releases-and-advisories/2026-news-releases-and-advisories/california-secretary-state-shirley-n-weber-phd-announces-new-measure-eligible-november-2026-general-election-ballot-imposes-one)[[^]](https://apnews.com/article/california-billionaire-tax-ballot-healthcare-measure-9edd9fb1cb2e7f0717b5b1b620fd0e05). The initiative faces substantial hurdles, including strong opposition from Gov. Gavin Newsom and anticipated significant financial pushback [[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://apnews.com/article/california-billionaire-tax-ballot-healthcare-measure-9edd9fb1cb2e7f0717b5b1b620fd0e05)[[^]](https://calmatters.org/politics/2026/06/california-unions-billionaire-tax-ballot/)[[^]](https://news.ballotpedia.org/2026/06/18/california-billionaires-tax-qualifies-for-the-november-ballot-competing-measures-pending-signature-verification/). Its prospects are further complicated by the qualification of two competing constitutional amendments for the 2026 ballot, which aim to potentially restrict or nullify such tax measures [[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://apnews.com/article/california-billionaire-tax-ballot-healthcare-measure-9edd9fb1cb2e7f0717b5b1b620fd0e05)[[^]](https://calmatters.org/politics/2026/06/california-unions-billionaire-tax-ballot/)[[^]](https://news.ballotpedia.org/2026/06/18/california-billionaires-tax-qualifies-for-the-november-ballot-competing-measures-pending-signature-verification/)[[^]](https://news.ballotpedia.org/2026/06/24/california-billionaires-tax-qualifies-for-the-nov-3-ballot/)[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/). Although recent polling indicates slight majority statewide support, historical trends suggest that support often diminishes closer to an election, and intense opposition spending is expected [[^]](https://www.marketplace.org/story/2026/08/04/californias-prop-40-wealth-tax-could-offset-100-billion-in-medicaid-cuts).

Comparing Proposition 40's campaign to past initiatives lacks sufficient research data. The available research does not provide adequate details on the campaigns of other progressive tax initiatives over the past decade to allow for a direct comparison of their strategies or challenges with the current effort for Proposition 40.

## What potential endorsements or opposition campaigns from major California business groups or public unions could significantly shift polling for Proposition 40 before November 2026?

Tax Rate | One-time 5% on net worth exceeding $1 billion (2)(3) [[^]](https://ballotpedia.org/2026_ballot_measure_polls) |
Early Voter Support | 50% (5) [[^]](https://ballotpedia.org/2026_ballot_measure_polls) |
Competing Amendments | Two (Propositions 41 and 42) (2)(5)(6)(7) [[^]](https://ballotpedia.org/2026_ballot_measure_polls) |

**Proposition 40 proposes a significant wealth tax to fund public services**

Proposition 40 proposes a significant wealth tax to fund public services. Sponsored by SEIU United Healthcare Workers West (UHW), this initiative suggests a one-time **5%** tax on net worth exceeding **$1** billion [[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://ballotpedia.org/California_Proposition_40,_One-Time_Wealth_Tax_for_State-Funded_Healthcare,_Education,_and_Food_Assistance_Programs_Initiative_(2026)). Funds generated would support state healthcare, food assistance, and education programs. Prominent supporters, including Senator Bernie Sanders and Representative Ro Khanna, advocate for the measure as a vital revenue tool for public services [[^]](https://ballotpedia.org/2026_ballot_measure_polls)[[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://news.ballotpedia.org/2026/06/24/california-billionaires-tax-qualifies-for-the-nov-3-ballot/).

Opposition to Proposition 40 raises economic stability concerns. Governor Gavin Newsom and various business interests, such as the California Business Roundtable, are leading the campaign against the measure, joined by individual donors like Peter Thiel and Reid Hoffman [[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://news.ballotpedia.org/2026/06/24/california-billionaires-tax-qualifies-for-the-nov-3-ballot/). These groups contend that Proposition 40 poses a risk to state economic stability and innovation, citing concerns about long-term fiscal impacts and a potential exodus of wealth from California [[^]](https://ballotpedia.org/2026_ballot_measure_polls)[[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/). While early polling indicates **50%** voter support for the measure, many voters reportedly share anxieties regarding the economic consequences if wealthy individuals and businesses were to leave the state [[^]](https://calmatters.org/politics/2026/06/california-unions-billionaire-tax-ballot/).

Competing ballot measures could challenge Proposition 40's efficacy. The landscape is further complicated by Propositions 41 and 42, two competing constitutional amendments that have also qualified for the November ballot [[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://calmatters.org/politics/2026/06/california-unions-billionaire-tax-ballot/)[[^]](https://news.ballotpedia.org/2026/06/18/california-billionaires-tax-qualifies-for-the-november-ballot-competing-measures-pending-signature-verification/)[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/). These measures, sponsored by Building a Better California and funded by Google co-founder Sergey Brin, aim to challenge the billionaire tax. They do so by mandating audits and imposing constraints on future tax initiatives [[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://calmatters.org/politics/2026/06/california-unions-billionaire-tax-ballot/)[[^]](https://news.ballotpedia.org/2026/06/18/california-billionaires-tax-qualifies-for-the-november-ballot-competing-measures-pending-signature-verification/)[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/). If Propositions 41 and 42 receive more votes than Proposition 40, they possess the potential to nullify it [[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://calmatters.org/politics/2026/06/california-unions-billionaire-tax-ballot/)[[^]](https://news.ballotpedia.org/2026/06/18/california-billionaires-tax-qualifies-for-the-november-ballot-competing-measures-pending-signature-verification/)[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/).

## What public polling data is available on California voter sentiment for Proposition 40, and which polling firms have been most accurate for past tax-related ballot measures?

Prop 40 Support (August 2026) | Majority among likely voters [[^]](https://www.ppic.org/publication/ppic-statewide-survey-californians-and-their-government-may-2026/) |
PPIC Poll (May 2026) | 54% in favor [[^]](https://www.ppic.org/publication/ppic-statewide-survey-californians-and-their-government-may-2026/)[[^]](https://www.ppic.org/press-release/becerra-hilton-lead-governors-race-majority-back-billionaire-wealth-tax/)[[^]](https://escholarship.org/content/qt1xq6d35m/qt1xq6d35m.pdf?v=lg) |
Yes on Prop 40 Internal Poll (July 2026) | 57% support [[^]](https://www.ppic.org/publication/ppic-statewide-survey-californians-and-their-government-may-2026/)[[^]](https://www.kcra.com/article/yes-on-prop-40-campaign-new-internal-poll-billionaire-tax/73300404) |

**California's Proposition 40 shows majority support in recent public polling**

California's Proposition 40 shows majority support in recent public polling. This measure, proposing a one-time **5%** tax on net worth exceeding **$1** billion for state residents, has successfully qualified for the November 3, 2026, ballot [[^]](https://www.sos.ca.gov/administration/news-releases-and-advisories/2026-news-releases-and-advisories/california-secretary-state-shirley-n-weber-phd-announces-new-measure-eligible-november-2026-general-election-ballot-imposes-one)[[^]](https://apnews.com/article/california-billionaire-tax-ballot-healthcare-measure-9edd9fb1cb2e7f0717b5b1b620fd0e05)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316176491.html)[[^]](https://www.sfchronicle.com/politics/article/billionaire-tax-qualifies-22228531.php)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316225859.html). As of August 2026, available public polling data indicates majority support among likely voters [[^]](https://www.ppic.org/publication/ppic-statewide-survey-californians-and-their-government-may-2026/). Specifically, the Public Policy Institute of California (PPIC) Statewide Survey in May 2026 reported **54%** in favor, while the UC Berkeley IGS Poll, also from May 2026, showed **52%** support [[^]](https://www.ppic.org/publication/ppic-statewide-survey-californians-and-their-government-may-2026/)[[^]](https://www.ppic.org/press-release/becerra-hilton-lead-governors-race-majority-back-billionaire-wealth-tax/)[[^]](https://escholarship.org/content/qt1xq6d35m/qt1xq6d35m.pdf?v=lg). An internal poll conducted by the 'Yes on Prop 40' campaign in July 2026 reported higher support at **57%** [[^]](https://www.ppic.org/publication/ppic-statewide-survey-californians-and-their-government-may-2026/)[[^]](https://www.kcra.com/article/yes-on-prop-40-campaign-new-internal-poll-billionaire-tax/73300404). Ballotpedia's indexing further reflects mixed public sentiment regarding Proposition 40 [[^]](https://ballotpedia.org/2026_ballot_measure_polls).

Historical accuracy data for polling firms on tax measures is limited. The Public Policy Institute of California (PPIC) is widely regarded as a reputable and nonpartisan firm frequently referenced for California ballot measures [[^]](https://www.lines.com/prediction-markets/elections/billionaire-one-time-wealth-tax-passes-in-california-election-2026). However, specific historical accuracy rankings for PPIC's projections on tax-related measures are not publicly quantified in its standard recent reports [[^]](https://www.lines.com/prediction-markets/elections/billionaire-one-time-wealth-tax-passes-in-california-election-2026). The available research does not provide information regarding the historical accuracy of other polling firms concerning tax-related ballot measures.

## What are the primary arguments from factions within the California Democratic Party who opposed the official endorsement of Proposition 40 in August 2026?

Prop 40 Tax Type | one-time 5% wealth tax on billionaires [[^]](https://calmatters.org/politics/2026/08/billionaire-tax-california-democrats-split/)[[^]](https://www.politico.com/news/2026/08/02/california-democratic-party-endorses-billionaire-tax-01021974)[[^]](https://www.sfchronicle.com/politics/article/california-billionaire-tax-prop-40-22370956.php)[[^]](https://www.kqed.org/news/12093726/california-democratic-party-endorses-billionaire-tax-splitting-with-newsom) |
Withdrawal Deadline | June 25, 2026 [[^]](https://news.ballotpedia.org/2026/06/24/california-billionaires-tax-qualifies-for-the-nov-3-ballot/)[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/) |
Opposition Descriptors | temporary, unreliable, and untested [[^]](https://calmatters.org/politics/2026/08/billionaire-tax-california-democrats-split/)[[^]](https://www.politico.com/news/2026/08/02/california-democratic-party-endorses-billionaire-tax-01021974)[[^]](https://www.sfchronicle.com/politics/article/california-billionaire-tax-prop-40-22370956.php)[[^]](https://www.kqed.org/news/12093726/california-democratic-party-endorses-billionaire-tax-splitting-with-newsom) |

**State leaders opposed Proposition 40, citing fiscal instability and economic harm**

State leaders opposed Proposition 40, citing fiscal instability and economic harm. Key figures within the California Democratic Party, including Governor Gavin Newsom and gubernatorial candidate Xavier Becerra, opposed Proposition 40, arguing it represented a "temporary," "unreliable," and "untested" fiscal solution that could harm the state's budget, economy, and long-term prospects [[^]](https://calmatters.org/politics/2026/08/billionaire-tax-california-democrats-split/)[[^]](https://www.politico.com/news/2026/08/02/california-democratic-party-endorses-billionaire-tax-01021974)[[^]](https://www.sfchronicle.com/politics/article/california-billionaire-tax-prop-40-22370956.php)[[^]](https://www.kqed.org/news/12093726/california-democratic-party-endorses-billionaire-tax-splitting-with-newsom). Governor Newsom and other state leaders reportedly engaged in negotiations with SEIU-UHW West, the measure's sponsor, attempting to persuade them to withdraw Proposition 40—a proposed one-time **5%** wealth tax on billionaires—before its June 25, 2026, ballot qualification deadline [[^]](https://calmatters.org/politics/2026/08/billionaire-tax-california-democrats-split/)[[^]](https://www.politico.com/news/2026/08/02/california-democratic-party-endorses-billionaire-tax-01021974)[[^]](https://www.sfchronicle.com/politics/article/california-billionaire-tax-prop-40-22370956.php)[[^]](https://www.kqed.org/news/12093726/california-democratic-party-endorses-billionaire-tax-splitting-with-newsom)[[^]](https://news.ballotpedia.org/2026/06/24/california-billionaires-tax-qualifies-for-the-nov-3-ballot/)[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/).

Various groups raised concerns about economic impact and fiscal solutions. Labor organizations, such as the California Teachers Association, voiced apprehension that the proposed tax could lead to ultrawealthy residents relocating out of state, thereby reducing future tax revenue and complicating efforts to renew existing taxes that support schools [[^]](https://www.politico.com/news/2026/08/02/california-democratic-party-endorses-billionaire-tax-01021974)[[^]](https://www.sfchronicle.com/politics/article/california-billionaire-tax-prop-40-22370956.php)[[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://apnews.com/article/california-billionaire-tax-ballot-healthcare-measure-9edd9fb1cb2e7f0717b5b1b620fd0e05). Opposition from healthcare-related groups arose from a perceived lack of consultation during the measure's development, with critics contending that it would not address the fundamental structural or long-term fiscal challenges facing the healthcare system [[^]](https://www.sfchronicle.com/politics/article/california-billionaire-tax-prop-40-22370956.php)[[^]](https://calmatters.org/california-voter-guide-2026/proposition-40-billionaire-tax/)[[^]](https://apnews.com/article/california-billionaire-tax-ballot-healthcare-measure-9edd9fb1cb2e7f0717b5b1b620fd0e05). Further opposition from Democratic-aligned interests is evident through competing ballot initiatives, financed by individuals like Google co-founder Sergey Brin, designed to nullify or restrict the billionaire tax and other new special taxes [[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/).

## What Could Change the Odds

**A one-time 5% wealth tax initiative, Proposition 40, has qualified for the California November 3, 2026, general election ballot [[^]](https://apnews.com/article/california-billionaire-tax-ballot-healthcare-measure-9edd9fb1cb2e7f0717b5b1b620fd0e05)[[^]](https://calmatters.org/politics/2026/06/california-unions-billionaire-tax-ballot/)[[^]](https://www.sfchronicle.com/politics/article/billionaire-tax-qualifies-22228531.php)[[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/).** The measure proposes a one-time **5%** tax on the net worth of individuals and trusts with assets over **$1** billion residing in California as of January 1, 2026 [[^]](https://ballotpedia.org/California_Proposition_40,_One-Time_Wealth_Tax_for_State-Funded_Healthcare,_Education,_and_Food_Assistance_Programs_Initiative_(2026))[[^]](https://news.ballotpedia.org/2026/06/24/california-billionaires-tax-qualifies-for-the-nov-3-ballot/)[[^]](https://news.ballotpedia.org/2026/04/29/signatures-submitted-for-california-initiative-enacting-one-time-billionaire-tax-for-healthcare-and-education-funding/). This initiative, which qualified on June 17, 2026, has not yet been voted on as of August 6, 2026 [[^]](https://news.ballotpedia.org/2026/06/24/california-billionaires-tax-qualifies-for-the-nov-3-ballot/)[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/). It aims to generate revenue for healthcare, education, and food assistance programs [[^]](https://calmatters.org/politics/2026/06/california-unions-billionaire-tax-ballot/)[[^]](https://www.sfchronicle.com/politics/article/billionaire-tax-qualifies-22228531.php)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html)[[^]](https://ballotpedia.org/California_Proposition_40,_One-Time_Wealth_Tax_for_State-Funded_Healthcare,_Education,_and_Food_Assistance_Programs_Initiative_(2026)).

**Competing measures, Proposition 41 (tax audits) and Proposition 42 (prohibiting new personal property taxes), have also qualified for the November 2026 ballot, doing so on June 24, 2026 [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/)[[^]](https://news.ballotpedia.org/2026/06/18/california-billionaires-tax-qualifies-for-the-november-ballot-competing-measures-pending-signature-verification/)[[^]](https://news.ballotpedia.org/2026/06/25/two-california-tax-initiatives-targeting-personal-asset-taxes-and-special-tax-rules-qualify-for-the-ballot-in-challenge-to-billionaires-tax-initiative/).** These are intended to nullify or undercut the wealth tax if both pass, with the measure receiving more votes prevailing in such an event [[^]](https://calmatters.org/politics/2026/06/california-ballot-measures-november-election/). The SEIU-United Healthcare Workers West backs Proposition 40, while opponents include California Governor Gavin Newsom and various business groups [[^]](https://calmatters.org/politics/2026/06/california-unions-billionaire-tax-ballot/)[[^]](https://www.sfchronicle.com/politics/article/billionaire-tax-qualifies-22228531.php)[[^]](https://www.sacbee.com/news/politics-government/capitol-alert/article316315507.html). Recent polling indicates voter division, with concerns regarding potential wealth flight and its impact on the state's long-term tax base [[^]](https://calmatters.org/politics/2026/06/california-unions-billionaire-tax-ballot/)[[^]](https://www.nytimes.com/interactive/polls/california-wealth-tax-polls-2026.html)[[^]](https://www.sfchronicle.com/politics/article/billionaire-tax-qualifies-22228531.php).

## Key Dates & Catalysts

- **Closes:** November 03, 2026

## Decision-Flipping Events

- A one-time **5%** wealth tax initiative, Proposition 40, has qualified for the California November 3, 2026, general election ballot [^] [^] [^] [^] .
- The measure proposes a one-time **5%** tax on the net worth of individuals and trusts with assets over **$1** billion residing in California as of January 1, 2026 [^] [^] [^] .
- This initiative, which qualified on June 17, 2026, has not yet been voted on as of August 6, 2026 [^] [^] .
- It aims to generate revenue for healthcare, education, and food assistance programs [^] [^] [^] [^] .

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