California voters have rejected Proposition 40, the ballot measure that would have imposed a one-time 5% tax on the wealth of the state's billionaires, after opponents poured a record-shattering sum of money into defeating it. The Associated Press called the race over the weekend, and NPR confirmed the measure failed after trailing for days as mail ballots were counted.

The scale of the opposition campaign was staggering even by California's standards. According to CalMatters, ultra-wealthy opponents funneled $378.4 million into killing Prop 40 — more than five times what the measure's backers, led by the health care workers' union SEIU-UHW, were able to raise in support.

A tax fight that split Democrats

Prop 40 didn't just divide California's electorate; it divided the state's dominant political party. Progressive Democrats championed it as a way to claw back revenue from a handful of residents with the means to absorb it, while business-aligned Democrats and the governor's allies worried it would accelerate an exodus of wealthy taxpayers and employers that the state has already struggled to stem. The opposition's war chest went in part toward two companion measures, Props 41 and 42, engineered by the same donors specifically to box in future wealth-tax efforts — the Washington Post reported Prop 42, which would make it harder for Sacramento to levy any future wealth tax, was itself narrowly ahead in late counting.

AT LEAST FIVE TIMES AS MUCH WAS SPENT OPPOSING THE MEASURE AS SUPPORTING IT

Supporters framed Prop 40 as a one-time fix aimed squarely at the state's wealth gap and its chronically strained budget. Opponents, backed heavily by tech and finance fortunes with deep ties to the state, argued it would set a precedent that could eventually widen to reach far more taxpayers than advertised, and ran a saturation advertising campaign warning of capital flight.

What comes next

SEIU-UHW, the measure's lead sponsor, says the defeat isn't the end of the push — the union has already signaled it intends to bring a similar wealth-tax measure back before California voters in 2028, betting that public appetite for taxing extreme wealth will keep growing even as this round's spending gap proved insurmountable. For now, California's billionaires keep their fortunes untouched by any state-level wealth levy, and the fight shifts to whatever comes of Prop 42's own, still-being-finalized result.