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Report: California's Proposed 'Billionaire Tax' Is Based on Bad Research

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Tuccille, J. (2026, September 18). Report: California's Proposed 'Billionaire Tax' Is Based on Bad Research. Reason. https://reason.com/2026/09/18/report-californias-proposed-billionaire-tax-is-based-on-bad-research/

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Reason · collected 2026-09-18 · by J.D. Tuccille

Quick Summary

California's proposed "billionaire tax," which aims to impose a one-time 5% tax on individuals with over $1 billion in assets, currently leads polls but faces opposition from Propositions 41 and 42. A recent report by Kristian Fors of the Independent Institute argues that this proposal is flawed, citing unreliable research by UC Berkeley professors Emmanuel Saez and Gabriel Zucman, who have previously estimated varying tax rates for high-income households, ranging from 36% to 23%. The report warns that these inconsistencies undermine the credibility of the proposed wealth tax, which could significantly harm California's economy.
Written by AI on 2026-09-18, from this article's own text only (the story summary below draws on all the coverage).

AI analysis

Story summary

California's proposed "billionaire tax," known as Proposition 40, faces a high-stakes battle leading up to midterm elections. A September poll by the Public Policy Institute of California showed 52 percent support for Proposition 40, which would impose a one-time 5% tax on individuals with assets over $1 billion. However, another measure, Proposition 41, has garnered 51 percent support and requires audits for new taxes and restricts how the wealth tax revenue can be used, potentially undermining Proposition 40's implementation. Critics argue that Proposition 40 is based on faulty research; economists Emmanuel Saez and Gabriel Zucman previously estimated a higher overall tax rate of around 36 percent for the top 1%, compared to the current proposal’s claim of a 23 percent rate for the top 400 richest households. This discrepancy raises concerns about the economic impact and validity of the proposed tax, especially as wealthy Californians are already considering leaving the state due to potential financial burdens.

Written for “California Billionaire Tax Proposal” on 2026-11-03, grounded in this article and the 0 other(s) covering the same event.

Story

📰 California Billionaire Tax Proposal
Economy/Business · 1 article(s) covering the same event.

Compared with similar articles

This article reads unscored and hedges 29% of its claims. Each row says how that neighbour differs.
New York Post
Hedges 8 of 30 claims Outlet record 66/100
“The articles discuss related issues concerning California's proposed 'billionaire tax', but describe different perspectives and warnings from different individuals at distinct times.”
How this article was measured signals, leaning charts, publisher record, byline, topics and claims

Signals How these are calculated →

Claims extracted
41
sentences that state something as happening or true
Uncertain
29%
12 of 41 hedged ("reportedly", "may", "according to")
Leaning
withheld
no quote in the article backed the model's score
Publisher signals
67/100
Reason's corrections and hedging, across everything collected from it. Not a measure of accuracy.
Outlets on this story
1
Economy/Business
Same framing elsewhere
1
articles that frame the event the way this one does
Analyzed 2026-09-18 · how these are computed

How this is being covered How these are calculated →

Article leaning vs. publisher reliability
Source leaning vs. consistency

Publisher

Reason · 1087 article(s) · 4 correction(s) detected
Running correction rate · 4 correction(s)

Who wrote this

J.D. Tuccille
16 article(s) here · 1 carrying a prediction
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Also by J.D. Tuccille
Nothing else under this byline is closely related to this article, so these are simply their most recent.
All 16 articles by J.D. Tuccille →

Topics

California Californians J.D. Proposition 40 Reason

Subjects

Saez PERSON · 5× Zucman PERSON · 5× California GPE · 4× Fors PERSON · 3× Californians NORP · 2× Independent Institute ORG · 2× Hoover Institution ORG · 1× J.D. ORG · 1× J.D. Tuccille PERSON · 1× Reason ORG · 1×

Narrative

But as Fors points out, the estimate that drew so much news coverage claimed that "the overall tax rate for the top 400 richest households in the nation was 23 percent," while just a year earlier, Saez and Zucman "estimated that the top 1 percent paid an overall tax rate of approximately 36 percent; the authors found a share of 41 percent for the top 0.001 percent of earners in the most recent year of their survey, a category encompassing billionaires and high multimillionaires."
framing: mixed · carried by 1 article(s) · first seen 2026-09-18
🔮 California's proposed "billionaire's tax" on the assets of wealthy state residents enjoys a slim lead in the polls leading up to the midterm elections, though so do two measures that, if they draw more votes, could render the scheme unenforceable.

Claims (41 extracted, 12 hedged)

California's proposed "billionaire's tax" on the assets of wealthy state residents enjoys a slim lead in the polls leading up to the midterm elections, though so do two measures that, if they draw more votes, could render the scheme unenforceable. uncertain
scheme → propose → votes
That makes for a high-stakes battle as many prosperous Californians are already fleeing to escape a tax that could force them to surrender ownership stakes in companies they've founded. uncertain
they → make → companies
Even if it doesn't pass, a new report warns that the proposal is based on faulty research and could do vast economic damage. uncertain
proposal → pass → damage
You are reading The Rattler from J.D. Tuccille and Reason. asserted
You → read → Tuccille
A Slight Polling Lead for the Wealth Tax—and for Opposing Measures A survey conducted September 4–10 by the Public Policy Institute of California found 52 percent support for Proposition 40, which would impose a (supposedly) one-time 5 percent tax on the wealth of people with assets worth over $1 billion. asserted
which → oppose → assets
Interestingly, 51 percent of respondents also support Proposition 41, which requires audits for new taxes and bars the way the wealth tax measure would allocate collected revenue, and 54 percent favor Proposition 42, which prohibits taxes on financial assets. asserted
which → support → assets
Under California law, "if provisions of two or more measures approved at the same election conflict, those of the measure receiving the highest affirmative vote prevail." asserted
those → approve → vote
Those conflicting measures could save Californians from themselves, since the proposed wealth tax is based on bad assumptions and would do enormous damage to the state's economy. uncertain
tax → conflict → economy
Unfortunately, much self-inflicted harm is already locked in. asserted
harm → inflict → ?
In March, a Hoover Institution study found that wealthy individuals leaving the state in fear of Proposition 40's passage had already removed "$536 billion, or nearly 30 percent of aggregate billionaire wealth, from the tax base." asserted
individuals → find → base
The Wealth Tax Scheme Is Based on Unusual Accounting Now, a new report finds the proposed wealth tax is not only dangerous for California's economic prospects; it's also based on bad research. asserted
it → base → research
According to the report's author, Independent Institute research fellow Kristian Fors, "this proposal has been heavily influenced by the work of UC Berkeley professors Emmanuel Saez and Gabriel Zucman to justify the concept of wealth taxation." uncertain
proposal → accord → taxation
Saez and Zucman have generated news headlines with their claims that the wealthy are undertaxed in comparison to lower-income Americans. uncertain
wealthy → generate → Americans
But as Fors points out, the estimate that drew so much news coverage claimed that "the overall tax rate for the top 400 richest households in the nation was 23 percent," while just a year earlier, Saez and Zucman "estimated that the top 1 percent paid an overall tax rate of approximately 36 percent; the authors found a share of 41 percent for the top 0.001 percent of earners in the most recent year of their survey, a category encompassing billionaires and high multimillionaires." asserted
authors → point → billionaires
The discrepancy, according to Fors, comes from how the economists treat corporate income taxes. uncertain
economists → accord → taxes
Conventional analysis assumes that corporate taxes burden shareholders, workers, and consumers as the tax gets passed on. asserted
tax → assume → shareholders
That results in the earlier estimate of a 41 percent tax rate for the wealthiest. asserted
That → result → wealthiest
To reach their much lower 23 percent estimated rate, Saez and Zucman used a non-standard analysis—and while the results of that approach won news coverage, they weren't subject to peer review. asserted
they → reach → review
"Saez and Zucman's empirical work on the California billionaire tax proposal retains these same unconventional accounting practices from 2019 without addressing their conflict with the mainstream corporate tax incidence literature," cautions Fors. asserted
Fors → retain → literature
The Independent Institute report observes that privacy laws prevented Saez and Zucman from drawing on personal income tax and other financial records. asserted
laws → observe → tax
They relied on the Forbes 400 list, and "a 2010 study by a group of IRS statisticians found that the Forbes 400 dramatically overestimates the net worth of individuals in their lifetimes when compared to probate records of their estates after death." asserted
Forbes → rely → death
Adjusting for that discrepancy produces estimates of "an average effective tax rate of 38 percent between 2018 and 2020, as compared to the 24 percent claimed by Saez and Zucman for this period. asserted
Adjusting → adjust → period
Other Economists Echo Criticism asserted
Economists → echo → Criticism
It should be noted that Fors isn't the first critic to call out Saez and Zucman. asserted
Fors → note → Saez
In 2019, economic historian Phil Magness wrote that the duo's much-publicized data "produced a flashy chart that purported to show the top 400 earners' tax rate dipping below the bottom half, this pattern also broke sharply from their own previous published work including a 2018 article with Thomas Piketty." asserted
pattern → write → Piketty
The earlier paper "showed a relatively flat pattern that only fluctuated year-to-year. asserted
that → show → year
In 2014 it had only changed 3 percentage points, sitting at 41%." asserted
it → change → %
Magness agreed with Fors that Saez's and Zucman's work "contradicted decades of scholarly literature on how to handle corporate tax incidence." asserted
work → agree → incidence
Fors also criticizes claims by Saez and Zucman that the rich avoid income taxes with a "buy, borrow, die" strategy of borrowing against net worth to fund their lifestyles. uncertain
Fors → criticize → lifestyles
"This strategy is not available only for those with an ultra-high net worth, but is also available to ordinary people," he notes, and it "only works if assets continue to appreciate." asserted
assets → note → people
If assets lose value, lenders can call in loans, and selling assets to meet obligations "can also trigger a massive tax liability if massive, unrealized capital gains are involved." asserted
gains → lose → liability
Strategies exist for reducing taxes, but they're not just for the super-rich and they're not risk-free. Forced To Sell or Flee Last asserted
they → exist → rich
, in an exchange with Rep. Ro Khanna (D–Calif.), businessman Mark Cuban warned that the wealth tax could force entrepreneurs with high paper value to sell stakes in their companies because "they are the definition of cash poor, stock rich." uncertain
they → warn → rich
Borrowing against shares to pay tax bills, as Khanna suggested, would be difficult for the founders of speculative start-ups. uncertain
Khanna → borrow → ups
Of course, one of the lowest-risk ways of minimizing exposure to high taxes is to leave jurisdictions that impose them. asserted
that → minimize → them
"Even the statistically improbable threat of a wealth tax is enough to provoke capital flight," notes Fors, who points to the high-profile departures of wealthy individuals who have brought vast amounts of capital with them to their new homes outside California. asserted
who → provoke → California
"Wealth is notoriously difficult to tax because of its mobility." asserted
Wealth → tax → mobility
"Over the years, California has continually embraced policies that have driven people and capital out of the state," Fors concludes. asserted
Fors → embrace → state
"If enacted, the billionaire wealth tax, and the precedent it sets, may be the straw that breaks the camel's back." uncertain
that → enact → back
Californians seem inclined to break their state's back with this ill-informed tax scheme. asserted
Californians → seem → scheme
…and 1 more, not listed.
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