Denial Rates by Insurer

Two people in the same county buy marketplace coverage for 2024. Both plans are ACA-qualified, cover the same essential health benefits, and follow the same federal rules. One insurer denied 3% of the in-network claims it received that year. Another denied 36%.¹ Nothing on either member card says which is which.

The spread is in the federal government's own files. Every issuer selling qualified health plans on HealthCare.gov must report the claims it received and the claims it denied, and KFF's analysis of the 2024 plan-year disclosures counts 157 reporting issuers with an average in-network denial rate of 19% — roughly one claim in five.¹ The average is the least informative number in the file. What it conceals is the range: issuers on the same exchange, selling to the same population under the same rules, denying at rates 33 percentage points apart.

The extremes are thinning, not the spread itself. In 2024, 3% of reporting issuers had in-network denial rates of 30% or higher — down from 17% in 2023.¹ The band most issuers occupy, though, still runs the width of the strip above, and where a given insurer sits inside it is knowable only from the disclosure data.

KFF tabulates the parent organizations whose HealthCare.gov subsidiaries received more than 5 million total claims in 2024 — nineteen of them, listed below. For in-network claims processed by these companies, the average denial rate was 19%, ranging from 8% at Elevance Health to 25% at Oscar Health.² Sort or filter the published table:

Read plainly: an in-network claim submitted to Oscar's marketplace plans in 2024 was about three times as likely to be denied as one submitted to Elevance's.²Volume compounds the point. GuideWell Mutual Holding, operating in a single HealthCare.gov state, received 68.9 million in-network claims and denied 15.4 million of them. Centene, the exchange's largest carrier by claims, received 93.1 million across 20 states and denied 17.2 million.² These are not edge cases; they are the bulk of the marketplace.

The table is also unstable year to year. Blue Cross Blue Shield of Alabama was the highest-denying large parent in 2023 at 35%; in 2024 it reported 19%.¹ Whatever drives swings of that size — product mix, claims-system changes, reporting practices — it is invisible in the data insurers file.

For a practice, this table reads differently than it does for a shopper. A clinic's denial workload is not just a function of how well it codes and documents — it is the product of visit volume, payer mix, and each payer's denial rate. Two practices with identical billing discipline can face very different piles of denied claims simply because one's marketplace panel skews toward an 8% parent and the other's toward a 25% one. The member card the front desk photocopies does not carry that number; the federal file does.

Two honest limits. First, a high denial rate is not, by itself, proof of wrongful denial — issuers differ in product design, membership, and the quality of the claims they receive, and the disclosure data cannot separate those causes. Second, the file barely explains itself: the most common denial reason issuers reported in 2024 was “Other”, at 36% of in-network denials, with 25% cited as administrative and only 5% as lack of medical necessity.¹ What the spread does establish is exposure — and what happens after denial makes exposure expensive. Fewer than 1% of the roughly 85 million denied in-network claims were appealed by consumers, and insurers upheld 66% of the appeals they saw.¹A denial that isn't contested is, in practice, a price cut nobody agreed to.

The disclosure regime that produced these numbers exists precisely so the market can price this in. So far, almost nobody does. The spread is public; it is simply unread.