Proponents of a proposal to tax California billionaires say they have obtained enough signatures for the measure to appear on the November ballot. 

The measure, proposed by Service Employees International Union-United Healthcare Workers West (SEIU-UHW), a union representing more than 120,000 California health care workers, would impose a one-time 5% tax on Californians with net worths of $1 billion or more.

The union said it obtained more than 1.5 million signatures, exceeding the 875,000 required to qualify for the ballot.

Called the "2026 Billionaire Tax Act," the statewide ballot measure is intended to prevent hospital and clinic closures across California and help fund public K-14 education and state food assistance programs, according to organizers. But the proposed tax has also proven divisive, with California Gov. Gavin Newsom arguing it could hurt the state's economy and budget if it drives its wealthiest residents to relocate.

Raising $100 billion

The tax is projected to raise about $100 billion over five years, according to an analysis by the Institute on Taxation and Economic Policy. 

Backers argue that the roughly 200 billionaires in California have collectively amassed $2 trillion in wealth, yet pay less than 1.5% of that in annual taxes — a fraction of the effective tax rate paid by middle-class residents. The state tax rate for single filers earning about $25,000 to $70,000 ranges from 4% to 8%.

Opponents of the proposal argue that it would drive wealthy Californians from the state. Billionaire hedge fund manager Bill Ackman, a New York resident, opposes the measure, saying he believes wealth taxes "effectively represent an expropriation of private property and have many unintended and negative consequences."

Suzanne Jimenez, chief of staff at SEIU-UHW, lead sponsor of the measure, said in a Monday statement that while "controversial billionaires" have tried to stop the measure from moving forward, "our current signature tally proves frontline healthcare workers will prevail in bringing this commonsense proposal to voters." 

"When our growing coalition files these signatures, David will have won the first round against Goliath, but healthcare workers and our allies won't quit until we fully protect our patients from the looming healthcare disaster that will be caused by $100 billion in cuts to California healthcare," she said.