---
title: "Fact Check: Could California Lawmakers Extend the Billionaire Tax to Everyone Else?"
description: "Opponents call Proposition 40 a Trojan horse, but legal experts say the tax’s own text limits how far the Legislature could go"
author: "rews desk"
published: 2026-10-02T12:00:00Z
modified: 2026-10-02T23:33:07Z
url: https://rews.cc/a/fact-check-could-california-lawmakers-extend-the-billionaire-31e55f
language: en
tags: ["politics", "tax", "prop-40", "billionaire-tax", "california", "us"]
publisher: "Rews (https://rews.cc)"
---

# Fact Check: Could California Lawmakers Extend the Billionaire Tax to Everyone Else?

*Opponents call Proposition 40 a Trojan horse, but legal experts say the tax’s own text limits how far the Legislature could go*

By rews desk · October 2, 2026 · https://rews.cc/a/fact-check-could-california-lawmakers-extend-the-billionaire-31e55f

## In brief

- Opponents’ ads say Prop. 40 lets lawmakers expand the billionaire tax to all Californians
- The measure allows amendments by two-thirds vote if they further the act’s purposes
- Experts said the text’s repeated reference to billionaire wealth limits how far changes could go
- The No campaign argues the measure’s stated purposes were written to permit a broader tax
- The November vote would be the first time voters directly decide a wealth tax

Opponents of Proposition 40, the one-time 5 percent tax on California billionaires that voters will decide next month, are airing ads that call the measure a “Trojan horse” lawmakers could expand to everyone. The claim is only partly true, legal experts said, and the ads leave out a fact that cuts against it: the measure writes the tax into the state Constitution.

The initiative, placed on the November ballot by Service Employees International Union-United Healthcare Workers West, includes language letting the Legislature amend it by a two-thirds vote “if the statute is consistent with and furthers the purposes of the 2026 Billionaire Tax Act.” That clause is where the fight starts.

Dave Regan, the union’s president, called the ads a scare tactic. “The billionaire tax is a tax on billionaires. Period. If you’re not a billionaire, you don’t pay the tax,” he said in a statement. Rob Lapsley, president of the California Business Roundtable, the group behind the ad, said voters deserve “to understand those issues and what they could mean for taxpayers and the state’s economy.” A separate billionaire-funded opposition group has said the initiative “gives politicians the power to expand the tax to anyone,” a claim at odds with the [election spending reported earlier](https://www.latimes.com/california/story/2026-10-01/2026-california-election-proposition-40-billionaire-tax-voter-guide).

The reality sits between the two. California courts have long given lawmakers authority to amend initiatives whose text permits it, and such clauses are common. Voters passed the Political Reform Act in 1974 and the Legislature has amended it almost continually since; the voter-approved millionaires’ tax for mental health has been amended 10 times since 2004, though never in its rate. “If it’s going to further the purposes, then they could,” said Megan Jones, a tax attorney at Holland & Knight.

But the courts look at what voters thought they were approving, said Michael Colantuono, an election law attorney, and Proposition 40’s text is specific. Its purpose section mentions “billionaire wealth” three times, and voter-guide arguments target roughly 200 California billionaires. “They could probably adjust the structure of the tax in marginal ways, but what they couldn’t do is make it a more than a one-time tax, and they probably couldn’t lower the threshold on wealth,” Mr. Colantuono said.

Kurt Oneto, a lawyer for the No on 40 campaign, countered in a statement that the measure’s purpose language “was carefully crafted to ensure that extending the tax to non-billionaires would be consistent with the measure,” pointing to its opening goal of protecting health care, education and food assistance. Any dispute, lawyers agree, would land in court. “Ultimately, it ends up in court,” said Chris Parker, a principal tax attorney at Baker Tilly.

Should it pass, the measure would build a new tax apparatus assigning value to startups, private businesses, art and car collections. “The excise tax that’s being proposed here is on potential,” Mr. Parker said. “The question then is, if we open the door to taxing potential, when does that stop?” Lawmakers have floated wealth taxes before and the bills have stalled; this is the first time voters themselves will decide one.

Mr. Colantuono noted one more check, a political one. Once a revenue stream funds services people value, he said, “there’s tremendous political pressure to prevent the sunset” — and temporary taxes in California have become permanent more than once.