State and federal wealth tax designs are shifting from speculative proposals to highly detailed, empirically modeled legislative and ballot…

TL;DR

State and federal wealth tax designs are shifting from speculative proposals to highly detailed, empirically modeled legislative and ballot battles. While new transaction-level research on California's ultra-wealthy challenges long-standing capital flight arguments, Washington State faces a high-stakes ballot fight that threatens broader social program funding, and federal lawmakers are leveraging post-Moore legal terrain to propose aggressive valuation reforms.

Subnational Revenue Realities and the "Missing Billionaire" Math

Granular transaction data is rewriting the debate over state-level wealth taxes by showing that billionaires pay far less under traditional income taxes than previously estimated, while revealing a large, unmapped tier of "small billionaires" that boosts potential revenues.

"...Alphabet founders Larry Page and Sergey Brin paid $0 in California individual income tax on their Alphabet wealth in 2019, 2020, and 2023. Alphabet paid no dividends, they reported no stock sales, and they accepted symbolic $1 salaries..." — California 2026 Initiative+1 (Source: NBER Working Paper No. 35218)

This empirical reality directly undermines opponents' arguments that a wealth tax would cause a net-negative revenue loss from capital flight. By showing that the wealthiest residents pay an effective income tax rate of just 0.07% of their wealth, researchers Jasper Boll, Emmanuel Saez, and Gabriel Zucman demonstrate that even aggressive departures would take a century of income tax losses to offset a one-time 5% wealth levy, especially when accounting for an estimated 617 actual billionaires in the state California 2026 Initiative+1.

What to watch: Watch whether other states adopt the "Pareto tail extrapolation" methodology to identify hidden fortunes when designing their own progressive tax brackets California 2026 Initiative+1.

State-Level Backlash and the Collateral Fiscal Risks of Tax Repeals

The conservative pushback against progressive state taxes is hitting a wall of public resistance and legal warnings that anti-tax initiatives could dismantle broader social safety net funding.

"...the initiative's broad drafting could have devastating, unintended consequences for the state's entire fiscal structure... [and] could also strike down payroll taxes that fund Washington's critical social safety net..." — Washington Constitutional Constraints (Source: Northwest Progressive Institute)

The aggressive push by opponents to repeal Washington's 9.9% millionaires' tax has backfired by exposing popular programs like Paid Family and Medical Leave to legal jeopardy Washington Constitutional Constraints. Early polling suggests that voters, having already rejected a capital gains tax repeal in 2024, are highly skeptical of these sweeping measures Washington Constitutional Constraints.

What to watch: Watch whether Washington voters reject Initiative Measure No. 26-645 this November, establishing a powerful precedent that progressive taxes on high earners can survive direct popular votes Washington Constitutional Constraints.

Federal Design Overhauling Valuation and Enforcement

Federal wealth tax proposals are shifting their focus from constitutional defense to the practical mechanics of asset valuation and massive IRS enforcement funding.

"...the bill explicitly authorizes the IRS to use 'formulaic valuation approaches for designated assets, including formulaic approaches based on proxies for determining presumptive valuations.'" — Federal Wealth Tax Proposals (Source: S. 4246 Legislative Text)

By providing a $100 billion funding boost and mandating formulaic valuation rules, Senator Elizabeth Warren's S. 4246 attempts to preemptively solve the historic administrative nightmare of valuing illiquid assets Federal Wealth Tax Proposals. This shows that federal proponents are no longer just debating the legality of taxing net wealth post-Moore, but are actively building the administrative machinery to enforce it Federal Wealth Tax Proposals.

What to watch: Watch whether the Treasury Department begins drafting preliminary guidance on formulaic proxies for illiquid private assets in anticipation of future legislative shifts Federal Wealth Tax Proposals.

What surprised us

• The "Small Billionaires" Gap: Standard journalistic lists like Forbes are highly accurate for ultra-visible multi-billionaires but miss a massive "small billionaire" tier California 2026 Initiative+1. Applying a Pareto tail extrapolation reveals there are actually an estimated 617 billionaires in California—368 more than listed by Forbes—representing a massive, untapped tax base California 2026 Initiative+1.
• The $0 Tax Years of Tech Giants: Despite generating billions in economic profits, prominent tech founders like Larry Page and Sergey Brin managed to pay exactly $0 in California individual income tax in multiple recent years California 2026 Initiative+1. This starkly illustrates how easily the ultra-wealthy can bypass traditional income taxation by avoiding stock sales and dividend distributions California 2026 Initiative+1.
• The Self-Defeating Nature of Repeal Initiatives: The broad drafting of anti-income tax initiatives can accidentally trigger catastrophic legal challenges to existing payroll taxes and social programs Washington Constitutional Constraints. Rather than just rolling back a millionaires' tax, Washington's repeal measure threatens to dismantle unemployment insurance and long-term care funding Washington Constitutional Constraints.