Free tool · CMS public data

Health Insurance Claim Denial Rates by Payer

Marketplace insurers denied 18.7% of in-network claims, and only 0.3% of those denials were ever appealed. When they were appealed, almost a third were overturned. This tool opens up the CMS Transparency in Coverage file for plan year 2026, so you can look up the real in-network denial rate, out-of-network denial rate, appeal overturn rate and denial-reason breakdown for any insurer on the federal Marketplace.

18.7%In-network claims denied across all reporting issuers
451,249,751In-network claims in the file, 84,502,749 denied
32.6%Of internal appeals were overturned
2.7% to 32.7%The spread between the lowest and highest issuer

Every figure here is calculated from one file: the CMS Transparency in Coverage Public Use File for plan year 2026. Nothing is estimated, scored by opinion, or submitted by users. The data covers Qualified Health Plans sold on the Federally-facilitated Exchanges and is self-reported by issuers to CMS. It does not cover Medicare Advantage, Medicaid managed care or employer-sponsored commercial plans. General reference information, not a coverage determination or legal advice.

What the numbers actually mean

The headline number most people quote is the in-network denial rate: the share of claims an issuer received for in-network services that it then denied. Across every issuer reporting for plan year 2026, that rate is 18.7% — roughly one claim in five. But the national figure hides an enormous spread. The lowest reporting issuer denied 2.7% of in-network claims. The highest denied 32.7%. That is a twelvefold difference between insurers operating under the same federal rules.

Out-of-network claims are denied at roughly double the in-network rate, 37.1% nationally. That gap is expected, but it is worth knowing the size of it before you write off an out-of-network balance as uncollectable.

The appeal gap is the finding worth acting on

262,982Internal appeals filed against 84.5 million denied in-network claims
32.6%Of those appeals were overturned in the filer’s favour
0.3%Of denials were appealed at all — three in every thousand

Put those numbers next to each other and the implication is hard to miss. Appeals succeed roughly a third of the time, and almost nobody files them. If your practice writes off denials without appealing, the CMS file suggests you are leaving a meaningful share of them on the table. The overturn rate varies by issuer, and you can check your specific payers in the tool above.

Denial reasons are reported, not guessed

The file breaks denials into ten categories, including whether a service was ruled not medically necessary, whether a referral was required, whether the member was not covered, and whether the denial was administrative. Notably, CMS collects separate counts for medical-necessity denials in behavioural health and everywhere else, which means behavioural health parity can be measured against an issuer’s own reported numbers rather than argued from anecdote.

How to read an issuer profile

A few cautions are built into the tool, and they matter if you plan to cite a number.

Volume first. Issuers reporting fewer than 10,000 in-network claims are hidden by default and excluded from the percentile ranking. A 33% denial rate calculated on 241 claims is noise, and it would be unfair to the issuer to put it at the top of a list. Switch them on with the low-volume toggle if you want to see them, and they are labelled when you do.

Suppressed cells are not zeros. CMS masks some values: an asterisk means the data was not available, a double asterisk means the cell was suppressed because it was too small, and N/A marks an issuer or plan new to the Exchange. Every one of those is left out of the totals here rather than counted as zero, which is why a denial-reason breakdown can add up to less than the issuer’s total denials.

Self-reported. CMS states plainly that all issuer and plan level claims data in this file is self-reported by the issuers. It is the best public data that exists on the question, and it is not an audit.

Sources and methodology

Source file: Transparency in Coverage PUF, plan year 2026, published by CMS on data.healthcare.gov. This tool reads the Individual Marketplace Medical QHP sheet.

Denial rate is calculated as issuer-level in-network claims denied divided by issuer-level in-network claims received. Out-of-network rate uses the equivalent out-of-network columns. Appeal overturn rates are the percentages CMS publishes at issuer level. Denial-reason counts are reported per plan and summed across each issuer’s plans. Percentile rank is computed on in-network denial rate across the 151 issuers reporting at least 10,000 in-network claims, where a higher percentile means fewer denials.

Colour bands compare an issuer against the national in-network rate rather than against a judgement: green is at or below 75% of the national rate, red is at or above 125% of it, amber is in between.