The Problem Room — The Data Record
UnitedHealthcare's Denial Rate
What the Data Shows
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.
The Short Answer — If You Came Here Looking for the Number
ACA Marketplace · 2023
33%
of in-network claims denied
4,670,649 denied of 14,022,287 received · 2nd highest of major insurers
ACA Marketplace · 2024
19%
of in-network claims denied
7,137,191 denied of 37,134,878 received · At industry average
Medicare Advantage · 2024
12.8%
prior auth requests denied
Highest denial rate of all major Medicare Advantage insurers
Source: KFF analysis of CMS Transparency in Coverage data for 2023 and 2024 plan years. KFF analysis of CMS Medicare Advantage prior authorization data for 2024.
On This Page
Section I · KFF · CMS Transparency Data · Updated September 2025
ACA Marketplace Denial Rates — 2023
KFF analyzed CMS Transparency in Coverage data for the 2023 plan year (data updated September 30, 2025, reflecting corrected data published by CMS). The dataset covers qualified health plans offered on HealthCare.gov — not state-based marketplaces, and not employer group plans. Among insurers that reported more than 5 million total claims, UnitedHealth Group had the second highest denial rate of any major insurer.
33%
UHC in-network denial rate
2nd highest of major insurers
4.67M
claims denied by UHC
of 14,022,287 received
20
HealthCare.gov states
where UHC reported 2023 data
20%
industry average
among all HealthCare.gov insurers
UHC's 33% denial rate is 65% above the industry average of 20%.
Major Insurer Comparison — 2023 ACA Marketplace
| Parent Company | Claims Received | Claims Denied | Denial Rate |
|---|---|---|---|
| Blue Cross Blue Shield of Alabama | 13,033,751 | 4,533,017 | 35% |
| UnitedHealth Group | 14,022,287 | 4,670,649 | 33% |
| Molina Healthcare | 5,339,437 | 1,407,854 | 26% |
| Health Care Service Corporation | 59,090,043 | 13,816,101 | 23% |
| CVS Health | 31,419,396 | 6,796,838 | 22% |
| Cigna Health | 18,151,575 | 3,777,467 | 21% |
| Industry average | — | — | 20% |
Appeals — 2023
<1%
of denied claims ever appealed
376,508 of 86 million denied
56%
of internal appeals upheld by insurer
211,383 of 376,508
3%
of upheld appeals taken to external review
~5,000 external appeals filed
40% of consumers didn't know they had a legal right to an external appeal. — KFF 2023 Consumer Survey
Source: KFF, "Claims Denials and Appeals in ACA Marketplace Plans in 2023," January 27, 2025 (data updated March 24, 2026 to reflect CMS corrections published September 2025). CMS Transparency in Coverage Public Use Files, 2023 plan year.
Section II · KFF · CMS Transparency Data · 2024 Plan Year
ACA Marketplace Denial Rates — 2024
UHC's ACA Marketplace denial rate dropped significantly from 33% in 2023 to 19% in 2024 — falling to the industry average. The industry overall showed less variability in 2024 than 2023. However, two data points require attention: UHC's total claims received more than doubled year-over-year (14M to 37M), and the insurer appeal uphold rate increased from 56% to 66% — meaning when patients did appeal, they were less likely to win in 2024 than 2023.
19%
UHC denial rate 2024
Down from 33% in 2023
7.14M
claims denied by UHC
of 37,134,878 received
19%
industry average 2024
Range: 8% (Elevance) to 25% (Oscar)
66%
appeals upheld by insurer
Up from 56% in 2023 — harder to win
Major Insurer Comparison — 2024 ACA Marketplace
| Parent Company | Claims Received | Claims Denied | Denial Rate |
|---|---|---|---|
| Oscar Health | 7,728,613 | 1,924,512 | 25% |
| Molina Healthcare | 6,278,416 | 1,408,843 | 22% |
| Cigna Health | 17,434,556 | 3,717,198 | 21% |
| UnitedHealth Group | 37,134,878 | 7,137,191 | 19% |
| Blue Cross Blue Shield of Alabama | 10,704,172 | 2,038,603 | 19% |
| Centene Corporation | 93,134,551 | 17,226,764 | 18% |
| Elevance Health | 14,691,239 | 1,224,517 | 8% |
Appeals — 2024
<1%
of denied claims appealed
262,982 of ~85 million denied
66%
of internal appeals upheld by insurer
Up from 56% in 2023
85M
total in-network claims denied
industry-wide, 2024
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.
Source: KFF, "Claims Denials and Appeals in ACA Marketplace Plans in 2024." CMS Transparency in Coverage Public Use Files for 2024 plan year.
Section III · KFF · CMS Medicare Advantage Data · 2024
Medicare Advantage Prior Authorization — 2024
Medicare Advantage insurers submitted nearly 53 million prior authorization requests to CMS in 2024 — a continued increase driven by growing MA enrollment (22 million people in 2019, 33 million in 2024). Of those, 4.1 million (7.7%) were denied in full or in part. UnitedHealth Group denied the highest share of prior authorization requests of any major Medicare Advantage insurer.
12.8%
UHC prior auth denial rate
Highest of all major MA insurers
52.8M
total MA prior auth requests
Up from 49.8M in 2023
4.1M
requests denied (7.7%)
Up from 6.4% in 2023
80.7%
of MA appeals overturned
More than 8 in 10 appeals won
UHC denied at 3× the rate of Elevance Health (4.2%) — the lowest major insurer.
Prior Authorization Denial Rates by Major Insurer — Medicare Advantage 2024
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
Source: KFF, "Medicare Advantage Insurers Made Nearly 53 Million Prior Authorization Determinations in 2024." CMS Medicare Limited Data Set, Contract Years 2022-2024 Part C and D Reporting Requirements.
Section IV · 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
8%
report PA led to disability, permanent damage, or death
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, Aetna), UHC was rated highest burden — with 65% of physicians rating UHC's PA program as "high" or "extremely high" burden.
65%
UnitedHealthcare
High/Extremely High Burden
75%
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. December 2025, n=1,000 practicing physicians. American Medical Association. © 2026 American Medical Association.
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.