42Bans new state taxes on owning personal property (stocks, accounts, etc.) and certain retroactive taxes

#Key findings

• $128.0M for Yes, one of the biggest Yes campaigns on the ballot (more than Prop 3's $74.8M or Prop 38's $71.3M), through one committee backed by Building a Better California (Brin $102M across its measures). ^[1][2]
• Its Yes committee is named "Protect Retirement & Life Savings" ^[1], but Prop 40 already generally excludes pensions and retirement accounts ^[3]. The people who benefit most from a permanent wealth-tax ban are those whose wealth sits in unrealized gains.
• It's permanent: it would take another statewide vote to ever allow a wealth tax in California. Wealth taxes have mostly disappeared abroad (12 OECD countries in 1990, 4 in 2017, and 3 in 2025 per the Tax Foundation). ^[4]
• Unlike most billionaire-backed measures, it has backing from Gov. Newsom plus police and fire unions ^[5] and the State Building Trades ^[6].

#Track record

#Money and conflicts

• Yes $128.0M. No $22.7M ($21.2M from SEIU-UHW's Prop 40 committee), through Oct 22, 2026. ^[1]
• Supporters: Building a Better California, Sergey Brin, Reform California, Peace Officers Research Association, California Professional Firefighters, State Building Trades ^[6], Gov. Newsom ^[5].
• The public-safety and construction unions are a notable crossover, since their members aren't the ones being taxed. I didn't find a public explanation of their reasons.

#Does it solve a lasting problem?

• It settles a policy question permanently in the Constitution instead of leaving it to future voters. Whether that's good depends on whether you want a wealth tax off the table for good. Its near-term purpose is to defeat Prop 40.

#If you vote yes: accountability

Bottom line: Prop 42 is a ban, so there's no new money to follow. What to watch is how courts read "personal property" and "retroactive," and whether the ban spills over onto taxes it wasn't aimed at. ^[7]

#Who's accountable

• The courts will define the edges of the ban. Expect lawsuits over any new state tax enacted after Jan 1, 2026. ^[6]
• The Legislature and the Franchise Tax Board would have to fit future tax laws within it.

#What to watch

• Any state tax bill that's challenged or dropped because of Prop 42.
• Lost revenue: the LAO says the effect on future revenue is unclear in size and timing, so watch for budget estimates. ^[7]

#Public records to request (CPRA)

Anyone can file a California Public Records Act request (the state's version of FOIA), with no reason required. Agencies must respond within 10 days, or 24 in unusual cases. ^[8] The Legislature isn't covered by the Public Records Act. Its records fall under a separate law, the Legislative Open Records Act.