Denial Rates by State

Once a year, a federal disclosure file makes it possible to ask a simple question: does where a claim is filed change how likely it is to be denied? For 2024, the answer is yes — by a factor of almost four. Insurers selling on HealthCare.gov denied roughly 85 million in-network claims, an average rate of 19%.¹ Behind that average, the state with the highest average in-network denial rate was Hawaii, at 27%; the lowest was South Dakota, at 7%.¹

The table below is the published record, not an estimate: the average in-network denial rate for each state in KFF’s analysis of the federal transparency data, alongside the lowest and highest issuer rate inside that state.² The 2024 file covers 156 insurers that reported receiving more than 1,000 claims, and their individual rates run from 3% to 36%¹ — so the spread matters as much as the rank. A state average is the average of whoever sells coverage there, and in thin markets it is largely one company’s number.

Read the bands before the ranks. In Texas, KFF notes, “the average denial rate for insurers … was about the same as the national average,” yet denial rates for its insurers “had greater variability than any other state included in this analysis, ranging from 12% to 36%.”¹ Hawaii’s 27% average sits at the very top of its own issuer range (5%–27%) — the state figure is effectively its dominant issuer’s figure. And the ranking is a photograph, not a fixture: in the 2023 data, the highest-denying state was Alabama, at 34%³; in the 2024 figure, Alabama shows 19%. A state’s position can turn on one issuer’s year.

Thirty states appear above. The rest are not low-denial states — they are invisible ones. The federal Transparency in Coverage file, the public’s only systematic source of denial rates, covers issuers on HealthCare.gov.⁴ States that run their own marketplaces — California, New York, Pennsylvania, Washington, and the rest of the state-based exchanges — file nothing into it. Georgia and Illinois used HealthCare.gov in 2024 but “have switched to operating their own marketplaces” since¹ — so the visible map is set to shrink further, not grow.

One state-based exchange offers a partial exception. California requires Covered California insurers to report comparable claims data, and in plan year 2023 those with complete data denied an average of 21% of in-network claims — “similar to HealthCare.gov insurers.”¹ That is the strongest evidence available that the hidden half of the map looks broadly like the visible half. But it is one state, one year. There is no true 50-state ranking of denial rates in public data; any map that shows one is interpolating.

The same file that exposes the denial rates also records what happens next: of the roughly 85 million denied in-network claims in 2024, consumers appealed less than 1%, and insurers upheld 66% of those appeals.¹ Past the internal appeal sits the step almost nobody takes — external review by an independent reviewer, outside the insurer. Marketplace enrollees filed at least 5,881 external appeals in 2024, about 4% of upheld internal appeals.¹ And unlike denial rates, that geography is mapped completely: every state and DC has an external-review path, either state-administered or through the federal HHS-administered process.