Insurers Sue Gavin Newsom Over Healthcare Tax
Doctors and health insurers in California have sued Gov. Gavin Newsom and the state Legislature over a new healthcare tax that they say could significantly increase insurance premiums for consumers. The lawsuit was filed with the California Supreme Court on October 5, 2026.
The dispute centers on California’s Managed Care Organization (MCO) tax, which has historically been used to help finance Medi-Cal, the state’s Medicaid program. The Legislature recently approved a substantial increase in the tax applied to private health plans.
The California Medical Association and California Association of Health Plans argue that the new tax conflicts with Proposition 35, a healthcare-related initiative approved by voters in 2024. They contend that Proposition 35 established limits on healthcare-related taxes and specified how the resulting revenue should be used.
The organizations argue that the state cannot effectively bypass those voter-approved restrictions by restructuring the tax. Their lawsuit asks the California Supreme Court to determine whether the Legislature and governor acted within the law when approving the new arrangement.
Health insurers warn that the increased tax will ultimately be passed along to consumers through higher premiums. They estimate that premiums could rise by roughly $100 per person annually, potentially adding about $400 a year for a family of four.
The potential increase would come on top of normal annual premium adjustments driven by medical costs and other factors. The insurers therefore argue that the tax could add another layer of financial pressure for Californians who purchase health coverage.
California officials defend the tax as part of an effort to maintain healthcare funding while responding to significant reductions in federal Medicaid funding. The state has argued that it needs additional flexibility to keep Medi-Cal financially sustainable.
The dispute is also connected to changes in federal rules governing healthcare-related taxes. Congress changed those rules, creating new restrictions on how states can use provider and health-plan taxes to generate Medicaid revenue. Federal officials have established new limits that began taking effect October 1, 2026.
California had used taxes on health insurers for more than two decades to help finance Medi-Cal. Historically, private health plans were taxed at a lower rate than Medi-Cal plans, but the Legislature’s latest action substantially increased the tax on private plans.
The state’s approach has involved seeking federal approval for different tax structures—one designed to comply with Proposition 35 and another designed to comply with federal requirements. The lawsuit argues that the resulting arrangement improperly circumvents the voter-approved initiative.
The case puts California’s healthcare financing system at the intersection of state voter initiatives, legislative authority and new federal Medicaid restrictions. Its outcome could determine how the state raises money for Medi-Cal and how much of those costs can be shifted onto privately insured Californians.
For consumers, the most immediate issue is whether the higher tax ultimately translates into higher premiums. For the state, the case could affect its ability to replace federal Medicaid funding and maintain financing for the millions of people covered through Medi-Cal.
Key Legal Outcome
- California doctors and health insurers filed a lawsuit challenging the new MCO healthcare tax.
- The plaintiffs argue that the tax violates restrictions established by Proposition 35.
- The lawsuit was filed with the California Supreme Court.
- Insurers estimate the tax could increase premiums by about $100 per person annually.
- California maintains that the tax is necessary to help address federal Medicaid funding reductions.
Why It Matters
- The case could affect healthcare premiums for millions of Californians.
- It tests the legal limits of voter-approved healthcare tax restrictions.
- The dispute comes as new federal limits on Medicaid-related taxes take effect.
- A ruling could influence how California finances Medi-Cal in future years.
- The case highlights the growing tension between state healthcare funding needs and federal Medicaid restrictions.
