Prop. 40 Without the Commercials: What California's Billionaire Tax Actually Says

I have been seeing a lot of commercials about California Proposition 40 lately, and depending on which commercial you watch, you would think we are voting on two completely different laws. One side describes a one-time tax on billionaires that will raise roughly $100 billion. The other warns that it is really a tax on every Californian—that everyone will have to disclose their finances under penalty of perjury, that retirement accounts are being taxed, and that the Legislature will be able to expand the tax to everyone later.

Those claims cannot all describe the same law. So I stopped listening to the commercials and read the measure. That turns out to matter here because the California Secretary of State explicitly warns voters that the arguments for and against ballot propositions are the opinions of their authors and have not been checked for accuracy by any official agency. (California Secretary of State)

Section 50301(a) applies the tax for the 2026 tax year to qualifying individuals with net worth of at least $1 billion and to certain trusts. The Legislative Analyst's Office describes it the same way: a one-time wealth tax on billionaires who were California residents on January 1, 2026. (Legislative Analyst's Office) So the claim that Proposition 40 currently taxes every Californian is not supported by the text. But "5 percent on wealth over $1 billion" is not quite how the formula works—Section 50301(b) phases the rate in between $1 billion and $1.1 billion, and the full 5 percent then applies to taxable net worth, not merely the dollars above $1 billion. (California Attorney General)

The opposition commercials do contain a real fact wrapped in misleading language. Section 50301(d) applies a new declaration requirement much more broadly than the tax itself. Every California resident required to file a 2026 income-tax return must either declare that their net assets were worth $1 billion or less, or submit the wealth-tax calculation. That is really in the measure. (California Attorney General) It is not the same as saying every Californian must inventory everything they own. California income-tax returns are already certified under penalties of perjury. (State of California Franchise Tax Board)

Directly held real property is excluded. (California Attorney General) Qualified pensions and IRAs are exempted, with an exception for Roth arrangements once their aggregate value exceeds $10 million. (California Attorney General) Section 50310 allows two-thirds Legislature amendments only if they are consistent with and further the purposes of a measure written around a narrowly applicable, one-time tax on billionaire wealth. (California Attorney General) A future Legislature could try to stretch that. That hypothetical is not the same as saying the current measure already taxes ordinary Californians.

Supporters say the measure will raise about $100 billion. The LAO estimates tens of billions of dollars spread over several years. (Legislative Analyst's Office) Other parts deserve scrutiny without exaggeration: temporary APA exemptions for FTB implementing regulations until 2028, up to ten years for certain deficiency assessments, and a tax obligation date of January 1, 2026—months before the November election. (California Attorney General)

After reading the measure: Proposition 40 creates a one-time wealth tax targeted at California billionaires, while also requiring every California resident who must file a 2026 income-tax return to declare whether their net assets exceed $1 billion. The supporter argument that this affects only billionaires leaves out that declaration. The opponent argument that it taxes everyone's savings, homes and retirement accounts goes much further than the text supports.

I'm not interested in telling anyone how to vote on it. But if we're going to decide something this consequential, we should at least be deciding based on the law that is actually printed on the ballot—not the version of it somebody bought thirty seconds of television time to sell us.

Read the full text of Initiative 25-0024A1, the 2026 Billionaire Tax Act.