The Problem Room — The Data Record
Health Insurance Companies'
Denial Rates — What the Data Shows
Denial rates for every major U.S. health insurer — nineteen companies, two years of data. Sourced entirely from federal CMS Transparency in Coverage data analyzed by KFF, and the 2025 AMA Prior Authorization Physician Survey. These are not estimates or advocacy numbers. They are what the government required insurers to report.
On This Page
- ⊕ Explore the Data — interactive, every insurer, 2023 & 2024
- I. Reading the Data — What the Numbers Do and Don't Say
- II. What Physicians Report — 2025 AMA Survey
- III. What They Actually Deny For — 2023 & 2024
- IV. The Alarm Rings Every Year — and the Fix Nobody Passed
- V. The Architecture — Why the Numbers Fit Together
- VI. Frequently Asked Questions
Interactive · KFF · CMS Federal Reporting Data · 2023 & 2024
Explore the Data — Every Insurer, Both Years
Pick a dataset, a year, and a company. Every number keeps its source link. The static tables this tool replaced covered seven insurers; this covers nineteen.
The Limits of the Instrument
What These Numbers Can't Show
The denials nobody tested
Fewer than 1% of ACA claim denials are ever appealed. No public dataset measures whether the other 99% were correct — not CMS, not the insurers' filings. Where systematic testing exists (Medicare Advantage appeals), roughly 8 in 10 tested denials failed the test. The accuracy of the untested pile is not a known number. It is a number the system was built not to produce.
The delay machine
Step therapy, fail-first protocols, and slow prior authorization never appear on this page — a claim that is stalled is not counted as denied. The most common form of harm, time, is structurally invisible in denial data. For what time costs when a treatable condition has a closing window, see the documented case in the Reason Room.
The unexplained third
The single largest denial reason both years is "Other reason not listed" — 34% of reasons in 2023, 36% in 2024. More than 28 million denials a year carry no stated reason at all. You cannot audit a reason that was never given.
The coverage most Americans actually have
This data covers HealthCare.gov marketplace plans; the Medicare Advantage data covers prior authorization only. Employer-sponsored insurance — the nation's largest source of private coverage — publishes no comparable denial data, even though the ACA requires transparency reporting for those plans. The requirement has simply never been implemented.
Every number above is a formal denial that got counted. The human cost — the grinding through step therapy, the prognosis windows that close during "process" — is the thing these numbers gesture at but cannot count. That silence is not a footnote to the data. It is a finding. No public data exists on the accuracy of the denials that were never appealed, and no denial statistic captures harm delivered as delay. That is why the clinical integrity question has to be asked — it cannot be answered from this page, and that is the point of asking it.
The Full Table — Every Major Insurer
Same data as the chart above, with raw claim counts where reported. The Total row covers the majors listed here (>5M claims each) — KFF's all-insurer average (across all ~175 HealthCare.gov insurers) is shown in the tiles above.
| Parent company | States | Claims received | Claims denied | Denial rate |
|---|---|---|---|---|
| Oscar Health | 14 | 7,728,613 | 1,924,512 | 25% |
| Molina Healthcare | 6 | 6,278,416 | 1,408,843 | 22% |
| GuideWell Mutual Holding | 1 | 68,858,890 | 15,397,985 | 22% |
| Harris Health | 1 | 6,776,421 | 1,449,319 | 21% |
| Cigna Health | 7 | 17,434,556 | 3,717,198 | 21% |
| BlueCross BlueShield of Tennessee | 1 | 6,270,421 | 1,323,501 | 21% |
| Blue Cross and Blue Shield of North Carolina | 1 | 16,183,703 | 3,116,071 | 19% |
| UnitedHealth Group | 19 | 37,134,878 | 7,137,191 | 19% |
| Blue Cross Blue Shield of Alabama | 1 | 10,704,172 | 2,038,603 | 19% |
| IHC Group | 1 | 8,402,145 | 1,571,221 | 19% |
| Centene Corporation | 20 | 93,134,551 | 17,226,764 | 18% |
| Health Care Service Corporation | 3 | 68,390,522 | 12,556,963 | 18% |
| CareSource | 5 | 8,845,681 | 1,588,363 | 18% |
| Louisiana Health Service | 1 | 6,465,640 | 1,140,936 | 18% |
| Blue Cross Blue Shield of Michigan | 1 | 5,206,241 | 866,555 | 17% |
| Arkansas Blue Cross Blue Shield | 1 | 6,568,033 | 1,041,647 | 16% |
| BlueCross BlueShield of South Carolina | 1 | 11,796,220 | 1,827,005 | 15% |
| Scott & White | 1 | 8,274,564 | 1,205,777 | 15% |
| Elevance Health | 7 | 14,691,239 | 1,224,517 | 8% |
| Total — all 19 majors | — | 409,144,906 | 77,762,971 | 19.0% |
Source registry — every dataset powering this page, with archived copies ▸
Source registry — carried through the reface
Every outbound source powering this explorer, plus the archived copy where one exists. This block is the contract: the rebuilt page ships with all of these intact.
Section I · What the Numbers Do — and Don't — Say
Reading the Data
The explorer above holds the full record — every major insurer, from UnitedHealth Group and Cigna to Centene — across both program types and both years. Two findings in it are easy to misread, so they get spelled out here.
What the Drop from 33% to 19% Means — And What It Doesn't
UHC's ACA Marketplace denial rate fell from 33% to 19% between 2023 and 2024 — a 14-point drop. Three factors likely contributed: increased regulatory scrutiny following the December 2024 killing of UHC's CEO, voluntary insurer pledges made in June 2025 to reform prior authorization (though the AMA survey found these had not yet made a meaningful difference as of December 2025), and UHC's announced reduction in the number of services subject to prior authorization.
However: UHC's total ACA Marketplace claims volume more than doubled from 2023 to 2024 (14M to 37M). A 19% denial rate on 37 million claims produces 7.1 million denied claims — more total denials than the 4.7 million denied at 33% in 2023. The rate improved. The volume of harm did not.
The 80.7% Appeal Overturn Rate — What It Means
Of the 11.5% of Medicare Advantage prior auth denials that were appealed, 80.7% were overturned. This has been above 80% across all years examined. In plain language: more than 8 in 10 prior authorization denials that patients challenged were found to be wrong. The care ordered by a physician, denied by the insurer, was deemed necessary after all — but only after the additional delay of the appeal process.
"These requests represent medical care that was ordered by a health care provider and ultimately deemed necessary but was potentially delayed because of the additional step of appealing the initial prior authorization decision. Such delays may have negative effects on a patient's health." — KFF
Even UnitedHealth's own denials were reversed 79.1% of the time on appeal in 2024 — about 4 in 5. The reversal isn't the exception; it's the rule. Which is what makes the <1% appeal rate the quiet part: how many wrongful denials simply stand because no one challenges them?
Sources: KFF analyses of CMS Transparency in Coverage data for the 2023 and 2024 plan years, and of CMS Medicare Advantage prior authorization data for 2024. Archived copies of all three are in the source registry above.
Section II · American Medical Association · December 2025 · n=1,000 Physicians
What Physicians Report — 2025 AMA Prior Authorization Survey
The AMA annually surveys 1,000 practicing physicians (400 primary care, 600 specialists) about their experiences with prior authorization. The 2025 survey was fielded in December 2025. It is the physician-side evidence of what the insurer-side denial rate data produces in clinical practice.
Patient Impact
95%
report PA causes care delays
92%
report significant negative impact on clinical outcomes
79%
report PA sometimes leads to treatment abandonment
26%
report PA led to a serious adverse event for a patient
The Life-and-Death Numbers
20%
of physicians report PA led to a patient's hospitalization
22%
report PA led to a life-threatening event or required intervention to prevent permanent impairment
Administrative Burden
40
PAs completed per physician, per week
13 hrs
spent per physician per week on PA
94%
report PA significantly increases physician burnout
UHC Rated Highest PA Burden of All Major Insurers
Physicians were asked to rate the burden of prior authorization for each major health plan. Of the four major national insurers (UHC, Humana, Anthem/Elevance, AetnaAetnaA major U.S. health insurer, acquired by CVS Health in 2018. Central to vertical integration concerns: CVS simultaneously owns Aetna (insurance), CVS Pharmacy, and CVS Caremark (PB…), UHC was rated highest burden — with 75% of physicians rating UHC's PA program as "high" or "extremely high" burden.
75%
UnitedHealthcare
High/Extremely High Burden
65%
Humana
High/Extremely High
61%
Anthem/Elevance
High/Extremely High
61%
Aetna
High/Extremely High
The Voluntary Pledge — What Physicians Found
On June 23, 2025, over 60 health insurers pledged voluntary reforms to PA programs. The AMA survey, fielded six months later in December 2025, found physicians reported little meaningful change:
Only 16% of physicians believe the insurer commitments will make a meaningful difference for patients and physicians.
Only 1 in 3 (33%) agree that PA denials for clinical factors are being reviewed by a licensed, qualified clinician — despite this being the one commitment already in effect at the time of the survey.
Only 1 in 4 (24%) of physicians participating in peer-to-peer reviews report that the health plan's "peer" often or always has the appropriate clinical qualifications.
74% report that the number of PA denials increased over the last five years.
Source: 2025 AMA Prior Authorization Physician Survey (archived copy). December 2025, n=1,000 practicing physicians. American Medical Association. © 2026 American Medical Association.
Section III · KFF · CMS Transparency in Coverage · 2023 & 2024
What They Actually Deny For
Before you scroll — take a guess
Of every claim denial, what share do you think is for "not medically necessary"?
That's the reason we're always given — the insurer protecting us from care we don't need. Drag to your guess.
Your guess
—
The real number
5–6%
2024: 5% · 2023: 6%
Denials are sold as a medical safeguard. Roughly 19 of every 20 denials cite something else. In 2024, "not medically necessary" was 5% of the reasons insurers reported — about 3.6 million physical-health denials plus 374,000 behavioral-health denials. In 2023 it was 6% (5% physical + 1% behavioral). The rest is "other," "administrative," excluded services, and benefit caps — the full breakdown, both years, is right below.
AbilityForge runs on no ads, no donations, and no store — just people who saw the gap between the story and the data. If this surprised you, that's exactly why we need the help.
→ Join the fightDenials are sold as a clinical safeguard — the insurer catching care that isn't medically necessary. The federal data says otherwise, and now says it two years in a row. The single largest category both years was "Other reason not listed" — 26.8 million unexplained denials in 2023, growing to 28.1 million in 2024. The insurer declined to name a reason at all.
Reasons Given for In-Network Claims Denials
The Tell — What's Missing From the Top of the List
If denials were mainly a clinical safeguard, "not medically necessary" would top the list. Instead it sits near the bottom both years — 6% of reasons in 2023, 5% in 2024. What tops the list is "Other" plus "Administrative" — and that opaque, paperwork-based share didn't shrink as denial rates fell: it grew, from 55% of all reasons in 2023 to 61% in 2024. The machinery justified as protecting patients from inappropriate care is, by its own reported reasons, mostly doing something else — and explaining itself less each year.
And a denial reason the insurer won't even name is the one hardest for a patient to fight — and the one likeliest to hide a wrongful denial.
Where an Investigation Would Start — An AbilityForge Hypothesis
If S.3829 becomes law and its wrongful-denial oversight takes effect, this taxonomy is the natural map — and the "Other reason not listed" category, now 28 million denials a year and growing, is where we'd expect the first shovel to go. You cannot audit a reason the insurer never stated. Forcing those unexplained denials into daylight is, we'd argue, exactly the kind of gap the legislation exists to close. (This is our analysis of the data — not a claim about the bill's specific text.)
Sources: KFF analysis of CMS Transparency in Coverage data — 2023 plan year (updated September 30, 2025) (archived copy), Table 2; 2024 plan year (archived copy), Table 2. Reasons are as reported by insurers to CMS; a claim may carry multiple reasons across resubmissions.
Section IV · The Recurrence — Measured, Mandated, Unanswered
The Alarm Rings Every Year — and the Fix Nobody Passed
This is not a one-year snapshot. The federal government now requires the alarm to ring: under the 2024 CMS Interoperability & Prior Authorization Rule, insurers must publicly post their prior-authorization metrics every year beginning in 2026. The data recurs, release after release, saying the same thing — and the response has never reached the core problem.
The Fix With Near-Universal Support — Still Not Law
The Improving Seniors' Timely Access to Care Act passed the U.S. House unanimously in 2022. It has been reintroduced every Congress since and currently carries 238 House and 63 Senate cosponsors — a supermajority in both chambers. It first stalled in the Senate over a $16 billion CBO score; later versions scored as cost-neutral — and it still is not law.
A bipartisan bill nearly all of Congress has signed, passed the House with zero "no" votes — and four years on, still unpassed.
And Even That Fix Doesn't Reach the Core
Everything moving in Washington — the Timely Access Act, the CMS rule — targets speed and disclosure: faster prior auth, published metrics. None of it makes a wrongful denial cost the party that made it. If all of it passed tomorrow, a denial like the ones documented on this page would still carry no consequence for the insurer.
Measurement without accountability is documentation of harm, not a remedy for it. (AbilityForge analysis.)
Members of Congress Have Named the Gap Themselves
"Now that insurance companies are making medical decisions for patients without a license — should they be held accountable?"— Rep. Neal Dunn, M.D. →
"I asked health insurance CEOs to raise their hands if they're penalized when patients are harmed by delays or wrongful denials. Not. One. Hand."— Rep. Kat Cammack →
The gap they name — insurers making clinical calls with no accountability when those calls harm patients — is the one the Clinical Integrity Amendment (S.3829+) is built to close.
Sources: Improving Seniors' Timely Access to Care Act of 2025 — S.1816 / H.R.3514, 119th Congress (Congress.gov). CMS Interoperability & Prior Authorization Final Rule (CMS-0057-F, 2024). Cosponsor counts as reported in the 119th Congress.
Section V — What the Numbers Mean Together
The Architecture — Why These Numbers Fit Together
The denial rate data, the appeal data, the Medicare Advantage prior authorization data, and the AMA survey are not separate stories. They describe the same mechanism from four different vantage points.
The Complete Picture — ACA Marketplace + Medicare Advantage + Physicians
UHC denied 33% of ACA Marketplace in-network claims in 2023 — 4.67 million denials.
Fewer than 1% of those denied claims were ever appealed. 59% of physicians don't appeal because they don't believe it will succeed based on past experience.
Of the tiny fraction that reached an Independent Review Entity, 85.2% were overturned against UHC's position — meaning independent physicians found UHC's denial was wrong in more than 8 of 10 reviewed cases.
In Medicare Advantage, UHC had the highest prior auth denial rate of any major insurer (12.8%) — despite having the fewest prior auth requests per enrollee, meaning UHC is uniquely selective about when they require prior auth and uniquely likely to deny it when they do.
95% of physicians report prior auth causes care delays. 22% report it led to a life-threatening event. The insurer's voluntary pledge to reform has been rated meaningful by only 16% of physicians.
The system denies at scale, relies on patients not appealing, overturns almost universally when challenged at independence, and has not meaningfully changed despite voluntary pledges. This is the documented argument for why structural legislative remedy is necessary.
They Knew
Scienter — The Evidence Record
The nH Predict 90% error rate deployed knowingly. The Natalie Collins training testimony. The DOJ investigations.
The Remedy Exists
S.3829 & S.3822 — The Legislation
The bills that close the structural gaps these numbers document.
The Human Cost
The Reason Room — Eleven Cases
These are the people the denial rate percentages ran through. Seven did not survive.
The Full Problem Record
The Problem Room
Systemic denial patterns, market power, government scrutiny, and the five-element fraud framework.
Section VI · Common Questions
Frequently Asked Questions
How many claims does UnitedHealthcare deny?
On the ACA marketplace, UnitedHealthcare denied 33% of in-network claims in 2023 (4,670,649 of 14,022,287) — the second-highest rate among major insurers — and 19% in 2024 (7,137,191 of 37,134,878). In Medicare Advantage, it denied 12.8% of prior-authorization requests in 2024, the highest rate of any major Medicare Advantage insurer. (Source: KFF analysis of federal CMS data.)
What is UnitedHealthcare's claim denial rate in 2025 or 2026?
The most recent comprehensive federal data covers the 2024 plan year (analyzed by KFF): 19% of ACA in-network claims and 12.8% of Medicare Advantage prior-authorization requests denied. CMS has not yet released complete 2025 or 2026 figures — insurers report this data on a lag — so anyone citing a precise 2025 or 2026 rate is estimating. We update this page as new federal data is published.
Why was my UnitedHealthcare claim denied?
The most common reasons are prior-authorization requirements, "not medically necessary" determinations, out-of-network or coding problems, and missing documentation. KFF found that for ACA plans the single most common denial reason given was a vague "other" — about a third of all denials. Fewer than 1% of denied claims are ever appealed, but a denial is not the final word: you have the right to appeal.
How do I appeal a UnitedHealthcare denial, and does appealing work?
Yes — appeals frequently succeed. Federal data shows that when Medicare Advantage prior-authorization denials are appealed, the large majority are overturned (about 85% for UnitedHealthcare). Yet fewer than 1% of denied claims are ever appealed, which is a major reason denials persist. You can request an internal appeal and, if it is denied, an external independent review.
Can UnitedHealthcare deny coverage for a preexisting condition?
No. Under the Affordable Care Act, ACA-compliant plans — including UnitedHealthcare's — cannot deny coverage, charge you more, or refuse to pay for essential health benefits because of a preexisting condition. This protection does not extend to short-term or non-ACA plans, which are not ACA-compliant.
Which major insurer has the highest claim denial rate?
It depends on the market. On the 2023 ACA marketplace, Blue Cross Blue Shield of Alabama had the highest in-network denial rate at 35%, with UnitedHealthcare second at 33% (against a roughly 19% industry average). In 2024 Medicare Advantage prior authorization, UnitedHealthcare had the highest denial rate of the major insurers at 12.8%.
What is the disadvantage of UnitedHealthcare for patients and seniors?
The principal documented disadvantage in the federal data is denial behavior: the highest Medicare Advantage prior-authorization denial rate among major insurers (12.8% in 2024) and historically one of the highest ACA in-network denial rates (33% in 2023). For seniors on Medicare Advantage, that means a higher likelihood of care being delayed or denied at the prior-authorization stage — denials that are often overturned on appeal, but only if the patient appeals.