California Prop 40 (2026): Billionaire Wealth Tax Odds for November 3
The official ballot title and the 5%-of-wealth mechanics, the November 3 election date, the verified Polymarket board with Yes at 29.5¢, the already-resolved ballot-qualification companion market, the written settlement rules, and the campaign timeline through Election Day.
Published October 7, 2026 · Election Day: Tuesday, November 3, 2026 · Next planned refresh: October 20, 2026 (T-14 window)
The answer first
Proposition 40 is on California's ballot for Tuesday, November 3, 2026, and a Yes vote means the state would collect a one-time tax from billionaires equal to 5 percent of their wealth. The official voter guide titles it “Imposes One-Time Tax on Certain Taxpayers. Initiative Constitutional Amendment and Statute.” — placed on the ballot by petition signatures, with revenue primarily for health care and exempted from the school-funding requirement and the state spending limit. The exact Polymarket contract Billionaire one-time wealth tax passes in California election 2026? was active and open at the October 7, 14:07 UTC check: Yes at 29.5¢, No at 70.5¢, about $3,885,188 in cumulative volume, $4,560 in 24-hour volume, and $153,607 in liquidity. A companion market asking whether the measure would reach the ballot resolved Yes at $1.00 after the June 25 certification cutoff. The outcome is unknown. This guide separates the fixed ballot facts from the changing market price and the written rules that control resolution.
What Proposition 40 does, in one view
One-time 5% tax
The measure imposes a 5% tax on certain taxpayers with assets over $1 billion. A Yes vote means the state collects it; a No vote means it does not.
Decided November 3, 2026
A statewide vote on the same ballot as California's open-seat governor race and the 2026 midterms.
Revenue for health care
Per the official summary, revenue goes primarily to health care and is exempted from the constitutional school-funding requirement and the state spending limit.
Yes at 29.5¢
At the October 7 snapshot the reviewed contract prices passage at 29.5¢ against 70.5¢ for No — an implied probability, not a promise.
$3.9M traded
Cumulative volume of $3,885,188 with $153,607 in liquidity and $4,560 in the last 24 hours — one of the largest ballot-measure markets of the cycle.
Ballot spot already settled
The companion contract “on California ballot?” resolved Yes at $1.00 ($247,103 volume) once the measure qualified as Proposition 40.
The fiscal note in the official guide estimates a temporary revenue increase of tens of billions of dollars spread over several years, and a possible ongoing decrease of less than $1 billion per year in income tax revenue from billionaires. Those are legislative-fiscal estimates of the measure's text, not forecasts of the vote.
Timeline to the Proposition 40 vote
The Polymarket event is created a year out: “Billionaire one-time wealth tax passes in California election 2026?”, together with a companion asking whether the measure makes the ballot at all.
The initiative qualifies by petition signatures — the official guide's designation “Put on the Ballot by Petition Signatures” — on a proposal first publicized by a healthcare union (the proposal's earliest coverage is linked in the market's own description).
The market's certification cutoff passes with the measure qualified as Proposition 40 on the Secretary of State's list. The companion “on California ballot?” contract resolves Yes at $1.00 on $247,103 of volume.
Poll coverage describes the measure losing ground: Politico (September 21) reports it losing support, and NBC News (September 30) reports voters back the tax but short of the majority support it needs.
CalMatters explains how the tax would work and how Propositions 41 and 42 could defeat it regardless (September 24, October 1, October 5); LA Public Press (October 5) maps that counter-measure dynamic; ABC News (October 3) and The American Prospect (October 6) cover the Democratic split; Politico (October 7) reports on billionaire relocations and the tax agency's response.
At 14:07 UTC the passage contract trades Yes 29.5¢ / No 70.5¢ with $3,885,188 cumulative volume and $153,607 liquidity. The continuously refreshed odds page carries the live board between refreshes.
Polls open 7 a.m. to 8 p.m. local time. Fourteen statewide propositions appear on the ballot, alongside the governor race and the federal midterms.
The market's API window closes the morning after (8:59 p.m. PT on election night). The end time is technical plumbing — settlement follows the written rules and official results, not the clock.
California processes a large volume of mail ballots, so a close result can take days or weeks; the Secretary of State's certification is the definitive step the market's resolution sources point to.
The verified Polymarket board
The exact public event reviewed for this guide is titled Billionaire one-time wealth tax passes in California election 2026? At 14:07 UTC on October 7 — the publication snapshot — its two-outcome board read:
| Outcome | Price | Event volume | Liquidity |
|---|---|---|---|
| Yes — the wealth-tax proposition passes | 29.5¢ | $3,885,188 | $153,607 |
| No — it does not pass | 70.5¢ | — | — |
Snapshot: Polymarket Gamma, October 7, 2026, 14:07 UTC. Prices are cents per share and move continuously; the two prices sum to exactly 100¢. Volume and liquidity are event-level fields from the same snapshot. The companion qualification market (resolved Yes, $247,103 lifetime volume) is a separate, closed contract.
A 29.5¢ Yes price says buyers currently pay 29.5 cents for a contract that pays $1 if the written resolution conditions are met — an implied probability of passage near 30%, against polling coverage in late September that reported support short of a majority. For how to read that gap — and why market prices and polls can disagree — see the site's guide to prediction markets versus traditional polling.
Resolution rules: what settles this market
The event's written description resolves the contract to Yes if any proposition containing a one-time tax targeting individuals, households, or family units with wealth, assets, or net worth of at least $1 billion passes in the named election, and to No otherwise. Three consequences follow. First, the unit is the proposition's passage — not signature counts, court rulings before the election, or the tax being collected. Second, the rules carry an integrity clause: if all qualifying propositions were removed from the ballot or amended before the election so that the main threshold dropped below $1 billion, the market resolves No. Third, the primary resolution source is official information from the State of California, with a consensus of credible reporting permitted as support — so the settlement window can extend past election night while mail ballots are counted, just as the market's end time (November 4, 04:59 UTC) is plumbing rather than a deadline for the result.
Why this page exists
Ballot-measure searches turn specific in the final three weeks of a campaign: the proposition number, what a Yes vote does, who supports and opposes it, and — for prediction-market readers — what the contract prices. This page is published 27 days out so search engines can index it before that wave, and it will be refreshed in the T-14 window (October 20), on Election Day, and at settlement. It joins the site's November 3 election cluster: the midterms balance-of-power hub, the California governor hub, and the November odds calendar.
California Proposition 40 FAQ
What is Proposition 40 on California's November 2026 ballot?
Proposition 40 is an initiative constitutional amendment and statute placed on the ballot by petition signatures. Its official title is “Imposes One-Time Tax on Certain Taxpayers.” It imposes a one-time 5% tax on certain taxpayers with assets over $1 billion, with revenue primarily for health care, and exempts that revenue from the constitutional school-funding requirement and the state spending limit.
When does California vote on Proposition 40?
Election Day is Tuesday, November 3, 2026, with polls open 7 a.m. to 8 p.m. local time. California counts a large volume of mail ballots, so a close result can take days or weeks to resolve definitively; the Secretary of State's certification follows in the weeks after Election Day.
What does the Polymarket market price for Prop 40?
At 14:07 UTC on October 7, 2026, the contract “Billionaire one-time wealth tax passes in California election 2026?” priced Yes at 29.5¢ and No at 70.5¢, with $3,885,188 in cumulative volume, $4,560 in 24-hour volume, and $153,607 in liquidity. Prices move continuously and are not polls or guarantees.
How does the Prop 40 market resolve?
The written rules resolve the market to Yes if any proposition containing a one-time tax targeting individuals, households, or family units with wealth, assets, or net worth of at least $1 billion passes in the November 3, 2026 election; otherwise No. The primary resolution source is official information from the State of California, with a consensus of credible reporting as a fallback. A companion market asking whether the measure would make the ballot already resolved Yes.
Could Prop 40 pass and the tax still not take effect?
That is a separate question from this market's settlement. The rules measure whether the tax proposition passes, not whether it survives later legal or constitutional friction. Reporting in October 2026 (LA Public Press, CalMatters) describes two other same-ballot measures, Propositions 41 and 42, that could constrain the tax's operation even if Proposition 40 passes — an implementation question the market does not settle.
When is this guide refreshed?
A planned refresh follows in the T-14 window around October 20, 2026, alongside the site's election-cluster updates, then an Election Day snapshot on November 3 and a settlement record once the result is resolved. Material developments — new polls, court action, or a substantial price move — can pull the refresh earlier.
Sources and verification
- California Secretary of State: Qualified Statewide Ballot Measures — Proposition 40's placement on the November 3, 2026 ballot and the full proposition list, including Propositions 41 and 42. Checked October 7, 2026.
- Official Voter Information Guide: Proposition 40 — official title, summary, fiscal impact, What Your Vote Means, and the pro/con arguments with listed supporters and opponents. Checked October 7, 2026.
- Polymarket Gamma: passage event — exact prices, volumes, liquidity, and the full resolution text. Checked October 7, 2026 at 14:07 UTC.
- Public Polymarket event page — live surface for the current order book. Companion ballot-qualification market: Gamma snapshot (resolved Yes, $247,103 volume).
- The union proposal's earliest coverage — the article the market's own description links for the proposal's origin.
- Campaign-status context is from October 2026 headline coverage indexed by Google News on October 7, 2026: Politico (September 21; October 7), NBC News (September 30), ABC News (October 3), The American Prospect (October 6), LA Public Press (October 5), and CalMatters (September 24; October 1; October 5). Poll findings are described only as reported in those headlines; no numbers are restated beyond them.
The October 7 publication run reviewed the complete blog archive, all 30 existing event hubs, the live sitemap, the auto-generated odds surfaces (including this market's own odds page, which serves the continuously-updating intent while this hub is the dated editorial guide), the proactive queue, and the latest local GSC snapshot. Exact and semantic scans found no editorial page targeting the Proposition 40 / California wealth-tax query family; the November odds calendar lists the market, and the governor and midterms hubs own adjacent intents. Demand evidence meets the pilot floor: $3.89M cumulative volume, $4,560 in 24-hour volume, and $153,607 in liquidity at the snapshot. Three contextual inbound links were added from the governor hub's Election Day timeline item, the midterms hub's “What is elected” FAQ (visible text and FAQPage schema together), and the blog election-betting guide, plus the events index listing.