---
title: "Why Health Insurers Deny Claims: Every Reason, Ranked"
url: "https://denialfacts.com/denial-reasons"
publisher: "Axion Labs — Denial Facts"
checked: "2026-11-04"
dataset_fixity: "sha256-cda2f9b89c8dde2a74989a35dbe7c0d08ff35dac5456484dc1c03c1b181a67b6"
---

# Why health insurers deny claims

## Figures

| Figure | Value |
| --- | --- |
| Categorized denials | 104,460,511 |

## What these categories are

Every denial has a category, and each category is beaten differently. These are the reasons insurers reported for 104,460,511 denied claims, this figure counts all categorized denials (in- and out-of-network), so it is larger than the 83,907,852 in-network figure cited elsewhere on the site. Find yours on the denial letter, it will use one of these categories or close to it. Then read the page for that reason: the argument that works is different for each.

## Every reason, ranked

| Reason | Claims | Share | Page |
| --- | --- | --- | --- |
| Other reasons | 33,793,471 | 32.4% | https://denialfacts.com/denial-reasons/other |
| Administrative reason | 17,933,106 | 17.2% | https://denialfacts.com/denial-reasons/administrative |
| Service excluded from the plan | 13,973,937 | 13.4% | https://denialfacts.com/denial-reasons/service-excluded |
| Referral required | 10,051,768 | 9.6% | https://denialfacts.com/denial-reasons/referral-required |
| Provider out of network | 9,391,760 | 9% | https://denialfacts.com/denial-reasons/out-of-network |
| Member not covered | 8,283,170 | 7.9% | https://denialfacts.com/denial-reasons/member-not-covered |
| Not medically necessary | 5,794,384 | 5.5% | https://denialfacts.com/denial-reasons/not-medically-necessary |
| Benefit limit reached | 5,147,025 | 4.9% | https://denialfacts.com/denial-reasons/benefit-limit-reached |
| Experimental or investigational | 91,890 | 0.1% | https://denialfacts.com/denial-reasons/experimental-investigational |

## What this hub is for

Every denial has a category, and the argument that works is different for each one. Find the wording on your own letter first, then read that page, not the other way around. If the letter is vague enough that none of these obviously fits, that is itself the answer: ask them, in writing, for the specific reason and the plan provision behind it. You are entitled to that, it costs nothing, and it is the most useful thing you can send tonight. Axion Labs · hello@getaxionlabs.com

## Who wrote this, and when

By Axion Labs · August 19, 2026, updated November 4, 2026

## The two federal clocks

The clock your letter has to describe, in actual dates Whatever else is on the page, these two dates are the page. You have 180 days from the date on your denial notice to file the internal appeal, and then 4 months from the final internal denial to ask for an independent external review. If waiting would seriously jeopardize your health you can ask for both to be expedited, decided in about 72 hours . Both timeframes are federal, not your insurer's choice, 29 CFR 2560.503-1 ( PDF ) and 45 CFR 147.136 ( PDF ), in plain English at HealthCare.gov , and your own denial letter states the ones that govern your plan. The PDFs are the same sections on govinfo.gov, which serves them without a challenge page, so an automated reader can check these two dates as easily as you can.

## How rare the second appeal is

You are not alone, measured rather than said: 83,907,852 in-network claims were denied in a single plan year, and only 4,918 of them, one in 17,061, ever reached the independent review stage. Of the ones that did, 22.2% (1,092 of 4,918; interval 22.2-23.8% for counts CMS withheld; 32.6% without SelectHealth) were overturned.

## What is free here, and what the one paid thing costs

Denied a claim? Insurers upheld 165,863 of the 262,982 internal appeals counted in 2024, 63.1% ( KFF ). The win is at independent external review, and the only way to arrive there is to run the internal stage on time, in the right order, with the record intact. That sequence is what the Appeal Kit is. Get my Appeal Kit, $29 One payment. No subscription. No cut of your claim. Opens on screen the moment you pay. 14-day refund, no questions, one email to hello@getaxionlabs.com. Get my Appeal Kit, $29 Everything you need for your appeal: your two deadlines, the argument that fits your denial reason, the letters, a brief for your doctor on what the reviewer checks, and the external review request. One payment. No subscription. No cut of your claim. Opens on screen the moment you pay. 14-day refund, no questions, one email to hello@getaxionlabs.com.

## What we will not pretend

What we will not pretend. We cannot overturn your denial. Only your plan, or an independent reviewer, can do that. We cannot make your plan cover a service it genuinely excludes. We cannot guarantee external review applies to your denial. It covers medical judgment, experimental or investigational determinations, and rescission, a purely administrative denial may not qualify, and we say so on those pages rather than selling you past it. We have no customer testimonials and publish none. Our evidence is the federal dataset and the regulation cites, both of which you can check.

## Every page on this site

Home Start here Insurers By company States Denial reasons Use cases How to appeal Ranked by denial rate The external-review gap Write the letter, free Deadline calculator Self-funded plan? Prior authorization denied Medicare WISeR denial Denial code CO-50 Before you call a lawyer Attorney for a denied claim Your denial letter United Healthcare denying claims Time limits on a claim Appeal a Medicare denial About Editorial policy How we compare Privacy Terms For machines: llms.txt openapi.json changes.json the composed answer this page as markdown

## Which release these figures are

Which release these figures are Every number on this page is the plan-year 2027 Transparency in Coverage file, issued October 22, 2026, covering plan-year 2025 claims. This is the newest plan year CMS has published: there is no Transparency in Coverage file for a plan year after 2027. The dataset list is at data.healthcare.gov . A test in this site’s build fetches that list on every run and fails if CMS publishes a plan year we have not acknowledged here. Every earlier release, plan-year 2024, plan-year 2025, plan-year 2026, is kept alongside it so the record is visible rather than a single year’s snapshot; /about says what changed between them. From the plan-year 2024 release to the plan-year 2026 release, external reviews filed went from 2,336 to 5,881. Overturned reviews went from 32.8% in the plan-year 2026 release to 22.2% in plan-year 2027, or from 32.6% to 32.6% without SelectHealth. We do not compare filed or overturned counts across plan-years 2026 and 2027. Some issuers may have counted pre-service appeals in their 2026 cells.

## Where these numbers come from

Where these numbers come from Counts: CMS Transparency in Coverage Public Use File (PY2027 release, PY2025 claims), data.healthcare.gov — US Government public domain . Rights and timeframes: 29 CFR 2560.503-1 (180 days, and your free right to the claim file) and 45 CFR 147.136 (4 months, and what qualifies), explained at HealthCare.gov . Expedited review is decided in about 72 hours under both sections. Reading either regulation from a script rather than a browser: eCFR answers automated fetches with a challenge page, so the same two sections are mirrored as government PDFs at govinfo.gov (29 CFR 2560.503-1) and govinfo.gov (45 CFR 147.136) .

## Who publishes this

Denial Facts publishes federal data about health insurance claim denials. We are independent: not affiliated with, endorsed by, or acting for any insurer, government agency, or review organization. We are not a law firm, a medical provider, or an insurance producer, and nothing here is legal, medical, or insurance advice. Data: CMS Transparency in Coverage Public Use File (PY2027 release, PY2025 claims), data.healthcare.gov — US Government public domain. Figures cover individual-market Qualified Health Plans on the federal Exchange and come from the plan-year 2027 release, issued October 22, 2026, covering plan-year 2025 claims. This is the newest plan year CMS has published: there is no Transparency in Coverage file for a plan year after 2027. See where the data comes from .

## Not advice

This page presents federal statistics and a general description of appeal rights created by federal law. It is not legal, medical, or insurance advice, and no outcome is guaranteed. Your denial letter and plan documents govern your specific case. Free help is available from your state's Consumer Assistance Program and from the federal Marketplace at HealthCare.gov.

## Sources

- CMS Transparency in Coverage Public Use File (PY2027 release, PY2025 claims), data.healthcare.gov — US Government public domain: https://data.healthcare.gov/
- 29 CFR 2560.503-1 (180 days, and your free right to the claim file): https://www.ecfr.gov/current/title-29/section-2560.503-1
- 45 CFR 147.136 (4 months, and what qualifies): https://www.ecfr.gov/current/title-45/section-147.136
- HealthCare.gov on external review: https://www.healthcare.gov/appeal-insurance-company-decision/external-review/

Cite: Axion Labs — Denial Facts, "Why Health Insurers Deny Claims: Every Reason, Ranked", https://denialfacts.com/denial-reasons (checked 2026-11-04). free to quote with the URL.