A controversial billionaire tax measure in California — which has secured enough signatures to appear on the November ballot — would devastate the state’s economy, a new study published Monday shows.

More than 108,000 jobs could be lost if the tax goes into effect, the analysis concluded, and $28 billion worth of wages would also be lost in California.

“For everyday Californians, these are not abstract numbers. They represent fewer career opportunities in the state’s most dynamic industries and in the businesses that serve them,” the report said.

The study was commissioned by Stop the Squeeze, a committee run by veteran consultants Dan Newman and Brian Brokaw to oppose the tax initiative. The two have ties to Gov. Gavin Newsom (D), who publicly opposes the tax.

The tax — proposed by the Service Employees International Union–United Healthcare Workers West — would impose a one-time 5% levy on California residents with assets exceeding $1 billion.

This is needed, the union said, to “prevent the collapse of California healthcare and help fund California public K-14 education and state food assistance programs.”

However, the study estimated that at least 40 ultra-wealthy Californians would leave the state as a result, meaning half of the $2 trillion held by the state’s billionaires would be gone. Already, a number of them have announced they’ve left California.

When such individuals leave, there is a loss of jobs with offices relocated, a reduction in consumer consumption and disruption to future jobs that would have been created, the report said. Those factors help contribute to the more than 108,000 jobs lost.

Overall, the study estimates $12 billion in annual personal income tax revenue losses by 2046, with a cumulative total of $122 billion over the next two decades. The lower tax revenue will hurt public services, the authors claimed.

Polls have suggested that a majority of Californians support the billionaire tax proposal, but opponents are putting up a fight.

Multiple competing ballot initiatives have been propped up. If they gain more votes, they could override the billionaire tax proposal.

One of them, titled the Transparency Act, would require audits of special state taxes and put those taxes under a spending limit. The act has enough signatures as well for the November ballot, backers announced on Monday.

“California families pay billions in state taxes every year and they deserve to see where that money goes and what it delivers,” said Tracy Hernandez, Co-Founder and CEO of the New California Coalition, which backs the Transparency Act.