Doctors and health insurers have filed suit alleging Gov. Gavin Newsom and the California Legislature violated the law when they approved a healthcare tax that could substantially increase insurance premiums.

KRISTEN HWANG/CalMatters Doctors and health insurers filed a lawsuit Friday alleging Gov. Gavin Newsom and the Legislature violated the law when they approved a healthcare tax that could substantially increase insurance premiums for Californians The lawsuit claims the recently passed tax on health plans, known as the managed care organization tax or MCO tax, circumvents a 2024 initiative that limits healthcare taxes and directs revenue toward specific purposes. The California Medical Association and California Association of Health Plans filed the complaint with the California Supreme Court“California voters passed Proposition 35 and made it law. The state does not get to ignore that law simply because following the law is inconvenient,” medical association CEO Dustin Corcoran said in a statement.

Tara Gallegos, a spokesperson for Newsom, said the tax allows the state to make changes to fund healthcare. “The state disagrees with their claims, and we believe the courts will too,” Gallegos said in an H.D. Palmer, a spokesperson for the Department of Finance, said in a previous statement to CalMatters that the state wanted to balance the affordability concerns of privately insured patients against large-scale federal Medi-Cal cuts.

Newsom stopped short of opposing the 2024 initiative when it was on the ballot, but he warned at the time it would “hamstring” the state budget.

For more than 20 years, California has levied taxes on health insurers to help fund Medi-Cal, the state’s insurance program for low-income people. The state historically taxed private health plans at a lower rate than Medi-Cal insurers, but in June, the Legislature passed a bill substantially raising the tax on private plans.

Health insurers said they will pass the cost directly on to consumers, spiking premiums by about $100 per person each year. That means a family of four could pay a $400 annual increase. That would come on top of the rate increases people typically see year to year.

“California is breaking the law by blowing through a tax limit voters put in place to protect Californians and businesses from higher health care costs,” said Charles Bacchi, CEO of the health plans association.

Doctors, hospitals, clinics and Medi-Cal insurers have argued for many years that the revenue from the tax should go toward improving Medi-Cal. They said that the state was inappropriately using the money to replace general fund spending, and that many providers were being paid far less than their services cost. In 2024, they asked voters to approve a limited tax that would be reserved for Medi-Cal improvements.

But Congress last year changed the rules on taxes used to generate revenue for healthcare, including the ones imposed on health plans. Rather than lose the money generated by the tax, Newsom proposed and the Legislature agreed to submit two taxes to the federal government for approval: one that complied with the 2024 initiative but would be rejected by the feds, and one that complied with federal regulations and largely disregarded the initiative. This story was originally published by CalMatters and distributed through a partnership with The Associated Press.