Full Breakdown
California’s Billionaire Wealth Tax Faces Tight Race Ahead of November Ballot
8/17/2026, 6:31:57 AM
Core Event – Proposition 40 Wealth Tax on the November Ballot
Proposition 40 proposes a one-time 5 % tax on the assets of California residents whose net worth exceeds $1 billion as of Jan. 1 2026. The tax would be applied retroactively and the revenue is earmarked to offset projected $100 billion cuts to federal health-care programs. The measure qualified for the November statewide ballot alongside 13 other initiatives.
Background & Context
The initiative was drafted by the Service Employees International Union’s health-care workers’ arm (SEIU-UHW West) after federal health-care reductions were approved. Supporters say the tax will generate billions for California’s health-care and education systems; opponents argue it could accelerate the outflow of wealth and investment from the state.
Data & Statistics – Poll Numbers and Taxpayer Outflow
- A UC Berkeley Institute of Governmental Studies (IGS) poll of 4,207 registered voters (2,310 likely voters) conducted Aug. 3-9 found 48 % of likely voters support Proposition 40, 41 % oppose it, and 11 % are undecided.
- The poll shows partisan polarization: 70 % of Democrats back the tax, while 80 % of Republicans oppose it. Voters with no party preference are split 50 %–39 % in favor.
- IRS data compiled from federal returns reveal a continuing exodus of high-income filers: Los Angeles County recorded a net loss of 17,496 tax filers who took nearly $1.9 billion in income to other states; Orange, San Diego, Riverside and San Bernardino counties also posted double-digit net losses.
Official Statements & Responses
- Billionaire investor Mark Cuban warned the tax could prompt wealthy residents and multi-billion-dollar startups to relocate out of California.
- Eric Schickler, co-director of the IGS poll, said the initiative is shaping up as a closely fought contest, with the key question being whether opponents can make inroads among traditionally Democratic-leaning voters.
- Governor Gavin Newsom expressed concern that the tax could further damage California’s volatile budget, which relies heavily on high-net-worth taxpayers.
- Senator Bernie Sanders (I-VT) called the tax “modest” and necessary to help Californians facing cuts to health-care benefits.
Criticism & Opposition
Governor Newsom warned that the tax could “destroy the state’s economy” by accelerating the departure of high-income earners. Republican leaders have uniformly opposed the proposal, framing it as liberal overreach.
Verbatim Quotes
- “If this passes, and it doesn't directly impact me at all, I won't be a Cali resident, but you can bet if I'm investing in a multi billion dollar startup, I'm asking them to move from California first,” — Mark Cuban
- “These results suggest that the billionaires tax initiative is shaping up to be a closely fought contest, with the key question being whether opponents can make big enough inroads among the state’s traditionally Democratic-leaning voters,” — Eric Schickler
Conflicting Reports & Gaps
Both sources agree the race is close but differ on the exact level of opposition. The poll does not capture the views of voters who have not heard of the measure; roughly 30 % of respondents were unfamiliar with Proposition 40.
What’s Next – Election Timeline
- The June 2 primary will determine the top two candidates for the November general election, which will include Proposition 40 among the ballot measures.
- Campaigns for and against the wealth tax are expected to intensify in the weeks leading up to the November vote, with both sides seeking to sway undecided and independent voters.
