Health Insurance Competition and Market Share in Michigan
November 13, 2025
Insurance companies provided medical coverage for over 9.5 million people in Michigan, as of June 30, 2025, based on enrollment reported in Mark Farrah Associates’ (MFA’s) County Health CoverageTM. As a mix of national and regional insurance carriers do business in its 83 counties, Michigan is an ideal state to examine. The focus of this brief is Michigan’s top three counties based on total health enrollment – Wayne, Oakland, and Macomb Counties.
Competition and Market Share
In Michigan, four carriers provide health insurance to over 75% of the state’s entire insured population. BCBS of Michigan (MI) covers half of the state’s health insurance market, while Corewell Health, another regional insurer that offers plans in Michigan under its subsidiary Priority Health, covers 13% of the market. UnitedHealthcare and Centene (operating as Meridian Health), both national insurance carriers, each cover approximately 6% of the state’s insured residents. The remaining 24% of the state’s insured receive some form of medical coverage from one of thirty-three other carriers.
- Wayne County, the most populous county in Michigan, is largely insured by BCBS of MI, with 45% of the insured market. Corewell, UnitedHealthcare, and Centene cover roughly equivalent shares of Wayne County, with Corewell and Centene both having 9% and UnitedHealthcare having 8%. The remaining 29%, or roughly 541,000 insured, are covered by one of 19 other carriers, including Molina, which also covers 8% of the market.
- Oakland County is primarily insured by BCBS of MI and Corewell, with 71% of the county’s insured population covered by just these two carriers. Combined, UnitedHealthcare and Centene cover about 11%, or roughly 140,000 people, in Oakland County, while 18% of the county’s insured are covered by other providers.
- Macomb County, like Oakland, is largely covered by BCBS of MI and Corewell, representing a combined total of 61% of the county’s insured. BCBS of MI’s penetration in Macomb is stronger, as it covers more than four times as many people as Corewell in the county. The reliance on smaller insurers is more prevalent here than in Oakland, with 23%, or over 191,000 people seeking coverage from other insurers.
- For the over 9.5 million Michiganders across the state with health insurance, including those discussed above, seventeen insurers provided private enrollment, ten offered coverage through Medicaid programs, and thirty-one presented Medicare Advantage plans. Eight carriers, a combination of national, regional, and local companies, offered plans across all three enrollment types.
About County Health CoverageTM
County Health CoverageTM provides reliable estimates of health insurance enrollment and market share at the state, county, and Metropolitan Statistical Area (MSA) levels. Product features include company market share by county, company, and state for the Individual, Private Group Risk, Private Administrative Services Only (ASO), Managed Medicaid, Medicare Advantage, and stand-alone Prescription Drug Plan (PDP) segments. Breakdowns by product type (HMO, PPO, etc.) are also presented, as well as population demographics and interactive, visual mapping tools. To learn more, visit the product page - County Health CoverageTM.
About Mark Farrah Associates (MFA)
Mark Farrah Associates (MFA) is a leading data aggregator and publisher providing health plan market data and analysis tools for the healthcare industry. Our product portfolio includes Health Coverage Portal™, County Health Coverage™, Medicare Business Online™, Medicare Benefits Analyzer™, 5500 Employer Health PLUS, and Health Plans USA™. For more information about these products, refer to the brochures available under the Our Products section of the website or call 724-338-4100.
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