California’s billionaire tax gets a brutal reality check ahead of Election Day – here’s what traders expect to pass

California’s billionaire tax is looking like a long shot, with prediction-market traders betting the controversial measure will go down in flames as voters prepare to decide 14 statewide propositions next week.

Kalshi and Polymarket International’s displayed markets put several proposals in strong positions, while others, including a voter ID requirement and a mandate for community health clinics, are drawing much lower passage estimates.

Here’s how the numbers stack up, according to the displayed market odds:

Housing and infrastructure

• Proposition 1 — Housing bonds: Authorizes $11.25 billion for veteran and affordable housing programs. Kalshi: 75% | Polymarket: 89%
• Proposition 37 — Homebuyer loans: Creates a state-backed low-cost loan and mortgage program for middle-income buyers of qualified new homes. Kalshi: 91% | Polymarket: 82%

State finances and elections

• Proposition 2 — Rainy Day Fund: Raises deposit limits and the maximum cap for the state’s reserve fund. Kalshi: 92% | Polymarket: 72%
• Proposition 4 — Public campaign financing: Repeals the prohibition on public funding for election campaigns. Kalshi: 9% | Polymarket: 22%
• Proposition 5 — Recall elections: Changes the recall process for statewide officers by removing the simultaneous successor election. Kalshi: 9% | Polymarket: 26%

Taxes and spending rules

• Proposition 3 — High-earner tax: Makes a temporary income tax increase permanent to fund public schools and health care. Kalshi: 95% | Polymarket: 94%
• Proposition 40 — Billionaire tax: Imposes a one-time wealth tax on billionaires to fund health care and educational facilities. Kalshi: 25% | Polymarket: 23%
• Proposition 41 — Tax spending limits and audits: Restricts new state taxes that fall outside specified spending-limit rules and requires independent audits of special tax revenue. Kalshi: 54% | Polymarket: 59%
• Proposition 42 — Property and retroactive taxes: Prohibits new state personal property taxes and retroactive tax legislation. Kalshi: 79% | Polymarket: 80%
• Proposition 43 — Local tax votes: Raises the voting threshold for certain local tax increases. Kalshi: 19% | Polymarket: 25%

Voting, health care and the environment

• Proposition 39 — Voter ID: Requires government-issued photo identification to vote. Kalshi: 14% | Polymarket: 21%
• Proposition 38 — Immunology research bonds: Authorizes $8.4 billion in state bonds for medical research facilities. Kalshi: 82% | Polymarket: 72%
• Proposition 44 — Clinic spending: Requires community health clinics to direct at least 90% of revenue toward patient programs and services. Kalshi: 8% | Polymarket: 11%
• Proposition 45 — Environmental review: Changes the CEQA review process for designated housing, transit and infrastructure projects. Kalshi: 32% | Polymarket: 37%

Californians can trade on these political outcomes because prediction-market contracts are treated under a different legal and regulatory framework from sports betting.

Federal law classifies prediction markets as financial derivatives rather than sports gambling, allowing platforms such as Kalshi and the US-regulated version of Polymarket to operate under that framework.