CALIFORNIA — Campaign finance records show the BUILDING A BETTER CALIFORNIA committee contributed $17,000,000 to the No on Prop 40 campaign on September 25, 2026. The Service Employees International Union, United Healthcare Workers West Nonprofit 501(c)(5) contributed $1,000,000 to the Yes on Prop 40 campaign on March 18, 2026. Primary source: quickguidetoprops.sos.ca.gov

Proposition 40 is an initiative constitutional amendment and statute that appears on the November 3, 2026, ballot in the state of California. The measure imposes a one-time tax on certain taxpayers with assets over $1 billion. Primary source: quickguidetoprops.sos.ca.gov

Under Proposition 40, billionaires who were residents of California on January 1, 2026, would pay a one-time state tax equal to 5 percent of their net worth. The wealth tax under Proposition 40 would be due in 2027. Taxpayers under Proposition 40 would have the option to spread payments over five years, but would have to pay more to do so. Real estate, pensions, and retirement accounts generally would be excluded from the Proposition 40 wealth tax.

Ninety percent of the revenue from the Proposition 40 wealth tax would have to be spent on health care services for the public. Existing rules in the State Constitution that limit spending and require the state to spend a certain amount on schools and community colleges would not apply to the revenue from the Proposition 40 wealth tax. Primary source: quickguidetoprops.sos.ca.gov

The Legislative Analyst estimates the state probably would collect tens of billions of dollars from the Proposition 40 wealth tax. The Legislative Analyst states that exactly when and how much the state would collect from the wealth tax is very hard to predict. The Legislative Analyst estimates that responses to the wealth tax probably would reduce state income tax revenues by less than $1 billion per year. Primary source: quickguidetoprops.sos.ca.gov

The Legislative Analyst states that the state would have costs to determine how much wealth tax is owed and to collect tax payments. The Legislative Analyst estimates that administrative costs for the wealth tax could be tens of millions of dollars per year for several years.

SEIU United Healthcare Workers West supports Proposition 40. U.S. Senator Bernie Sanders supports Proposition 40. The California School Boards Association opposes Proposition 40. Primary source: quickguidetoprops.sos.ca.gov

The SEIU United Health Care Workers West Political Issues Committee contributed $1,350,000 to the Yes on Prop 40 campaign on February 12, 2026. Ripple Labs contributed $5,000,000 to the No on Prop 40 campaign on February 11, 2026. The SEIU United Health Care Workers West Political Issues Committee contributed $2,348,319 to the Yes on Prop 40 campaign on March 10, 2026. Primary source: quickguidetoprops.sos.ca.gov

The BUILDING A BETTER CALIFORNIA committee contributed $15,000,000 to the No on Prop 40 campaign on September 18, 2026. Primary source: quickguidetoprops.sos.ca.gov