Once a year, one of the few hard numbers in American claims adjudication lands in a public file. Insurers selling qualified health plans on HealthCare.gov must report how many claims they received and how many they denied, and KFF's analysis of the 2024 file — published March 24, 2026 — found they denied approximately 19% of in-network claims: about 85 million denials out of roughly 451 million in-network claims submitted.1
Out of network, the rate nearly doubles, to 37%. Counting both, one in five claims filed under a HealthCare.gov marketplace plan in 2024 was denied — figures KFF describes as all similar to 2023.1 The denial, in other words, is not an edge case in this market. It is a fifth of the workload.
19%1
of in-network claims denied by HealthCare.gov insurers in 2024 — about 85 million claims
37%1
of out-of-network claims denied — nearly double the in-network rate
<1%1
of denied in-network claims were appealed by consumers
An average that hides a 33-point spread
The 19% average is real, but almost nobody experiences the average. Across the 157 insurers that met the reporting threshold in 2024, in-network denial rates ran from 3% to 36%.1 Which plan a patient picked matters more than the national number: the same claim, filed to two different issuers on the same exchange, can face a denial rate that differs by a factor of ten.
Sources 1, 4. 157 issuers with more than 1,000 claims reported; 'large parent' = parent companies with more than 5 million HealthCare.gov claims in 2024.
The extremes are not obscure regional carriers. Among parent organizations processing more than 5 million marketplace claims, the average was 19% — ranging from 8% at Elevance Health to 25% at Oscar Health.1 Becker's Payer Issues, working from the same file, lists household names across the top of the table.4
| Parent organization | In-network denial rate, 2024 |
|---|---|
| Oscar Health | 25% |
| Molina Healthcare | 22% |
| Guidewell Mutual Holding | 22% |
| Harris Health | 21% |
| Cigna | 21% |
| BCBS Tennessee | 21% |
| BCBS North Carolina | 19% |
| UnitedHealth Group | 19% |
| BCBS Alabama | 19% |
| IHC Group | 19% |
Ten highest average in-network denial rates among parent organizations with more than 5 million HealthCare.gov claims in 2024, rounded to the nearest point (source 4, from KFF's analysis of CMS data).
One structural change did show up in 2024: the extreme tail thinned. Only 3% of reporting insurers had in-network denial rates of 30% or more, down from 17% of insurers in 20234 — and the full range compressed from 1%–54% in 2023 to 3%–36% in 2024.2 The worst rates got less extreme. The middle of the distribution, where most claims live, did not move.
The largest reason on record is "Other"
The file also asks insurers why they denied. The largest single answer in 2024 was no answer at all: 36% of in-network denials were attributed to "Other" — a reason not on the list. Administrative reasons took another 25%. Medical necessity, the category around which the entire appeals apparatus is built, accounted for just 5% of reported denial reasons.1
Source 1. Shares of in-network denials; categories shown sum to 88% — the remainder falls across smaller reported categories. Reasons are not linked to the services denied (see methodology).
“Because the current data do not link denial reasons to the services that were denied, neither the share of total claims denied for a given reason nor the type of service most often denied can be calculated.”1
KFF, Claims Denials and Appeals in ACA Marketplace Plans in 2024
Three data years, one flat line
Set the 2024 brief against its predecessors and the picture is stability at a high level. KFF's brief on 2021 data put the in-network denial rate at nearly 17%.3 The 2023 figure was 20% — which HFMA noted was the highest since the marketplaces opened in 2015.25 The 2024 rate of roughly 19% sits within a point of that peak, and KFF itself calls the two years similar rather than a decline.1
Sources 1–3. KFF's published brief series has no standalone analysis of the 2022 data year. Reporting populations differ by year (162 issuers in 2021, 175 in 2023, 157 in 2024), so small year-over-year movements should not be over-read.
What happens after the denial
The file traces the aftermath too, and the funnel is steep. Of roughly 85 million denied in-network claims in 2024, HealthCare.gov consumers appealed at least 262,982 — under 1%. Insurers upheld 165,863 of those appeals, or 66%1 — up from a 56% uphold rate in 2023.2 Just 5,881 cases went on to external review, 4% of upheld internal appeals.1 Fighting a denial remained rare; in 2024, winning the internal fight got rarer as well.
| Stage | Count, 2024 | Share |
|---|---|---|
| In-network claims denied | ~85 million | 19% of ~451M received |
| Appealed internally by consumers | ≥262,982 | under 1% of denials |
| Denials upheld on internal appeal | 165,863 | 66% of appeals |
| Taken to external review | ≥5,881 | 4% of upheld appeals |
Source 1. Consumer appeals reported for HealthCare.gov plans; counts are floors — small cells are suppressed in the public file.
Sources
- 1KFF — Claims Denials and Appeals in ACA Marketplace Plans in 2024 (19% in-network; 37% out-of-network; 3%–36% issuer range; reasons; appeals funnel) · Mar 24, 2026 (2024 data)
- 2KFF — Claims Denials and Appeals in ACA Marketplace Plans in 2023 (20% in-network; 1%–54% issuer range; 56% uphold rate) · Jan 27, 2025 (2023 data)
- 3KFF — Claims Denials and Appeals in ACA Marketplace Plans (nearly 17% in-network in 2021; 162 reporting issuers) · Feb 9, 2023 (2021 data)
- 4Becker's Payer Issues — 10 ACA insurers with the highest claim denial rates: KFF (parent-company table; share of issuers at ≥30% fell from 17% to 3%) · Mar 25, 2026
- 5HFMA — ACA marketplace plans see highest denial rate in nine years (on the 2023 data) · Feb 3, 2025