Competition in U.S. Health Insurance Markets: AMA's Latest Report

AMA Data Shows Health Insurance Markets Are Getting Even More Concentrated

Health insurance market concentration is not a new story, but the newest national data suggests the trend is hardening in place. Using 2024 market figures and the Herfindahl Hirschman Index, the American Medical Association reports that 97% of metropolitan commercial health insurance markets are now “highly concentrated,” up from 95% a decade earlier. (American Medical Association)

For industry professionals, the implications are less about headlines and more about how concentration quietly reshapes everything downstream, from distribution economics to network strategy to employer negotiations.

What the Latest Numbers Actually Say

The AMA’s analysis looks at concentration across metropolitan statistical areas and classifies markets as highly concentrated when HHI scores exceed the thresholds used by federal antitrust regulators. In plain terms, it is a measurement of how much market power is sitting with a small number of carriers. (American Medical Association)

Two findings stand out for commercial coverage:

• Blue Cross Blue Shield affiliated plans held the largest commercial market share in 84% of metro areas, reflecting the breadth of the BCBS footprint. (American Medical Association)

• Nearly half of metro areas have one insurer controlling at least 50% of the commercial market, a level of dominance that makes “choice” feel theoretical for many employers and members. (Becker's Payer Issues | Payer News)

“In numerous metropolitan areas nationwide, a limited number of insurers control significant shares of the market, impacting consumer choice and increasing costs.”
John J. Whyte, MD, MPH, CEO and Executive Vice President, American Medical Association (American Medical Association)

Medicare Advantage: Slightly Less Concentrated, Still Dominated

Medicare Advantage shows modest improvement in concentration in some areas, but the leadership pattern remains similar. The AMA notes that MA markets still commonly feature a leading carrier with a very large share, and in many metros at least one plan crosses the 30% threshold. (American Medical Association)

A related takeaway for payers and agencies: even when concentration softens, market power tends to remain sticky because MA growth is fueled by brand familiarity, broker relationships, and operational scale.

Exchange Markets: Movement, But Not a Breakthrough

Individual exchange markets have been more dynamic than employer markets over the past decade, with entrants and exits shifting concentration year to year. The AMA’s latest update describes a pattern where concentration rose after the early exchange years and has since trended downward again, though the overall HHI level remains high. (American Medical Association)

For agency leaders, that “churn without true fragmentation” reality matters because it affects carrier participation, commission stability, and how often your book needs to adapt to new plan availability.

A Quick Concentration Snapshot

Here’s a simple way to frame what concentration levels often look like in practice.

(These structures align with how HHI-based classifications behave in real-world markets.) (American Medical Association)

What This Means for Agents, Agencies, and Carrier Partners

When markets concentrate, product differences can shrink, but distribution value can rise. Why? Because buyers still need help navigating networks, utilization controls, prior authorization realities, and the true total cost of coverage. In heavily concentrated markets, the advisory edge often comes from clarity and comparison discipline rather than “more options.”

One section with practical actions (bullet points):

• Build a local “carrier power map” for your metro area: who dominates large group, small group, and MA, and where the viable alternatives truly are. (American Medical Association)

• Lean harder into network literacy: dominant share carriers often have the broadest networks, but narrower products may be where savings and friction live.

• Watch exchange participation like a hawk: year-to-year carrier shifts can change retention risk, member disruption, and enrollment ops workload. (American Medical Association)

• For agency owners, concentration is a revenue concentration risk too: diversify carrier relationships and lines where feasible to reduce exposure to unilateral compensation or underwriting changes.

The Strategic Bottom Line

Concentration is not just a policy debate, it is a day-to-day operating reality for the insurance industry. The AMA’s data reinforces that most metropolitan commercial markets are firmly in “highly concentrated” territory, with dominant carriers continuing to widen their reach. (American Medical Association)

“The newest edition… analyzes 2024 data showing which health insurers hold the largest share… where limited competition leaves millions of Americans with too few choices and rising costs.”
American Medical Association, Press Release Statement (American Medical Association)