The Problem Room — The Data Record
Prior Authorization
Denial Rates by Insurer
For the first time, insurers had to publish their own numbers. Under a 2024 federal rule, every Medicare AdvantageMedicare AdvantageThe private-insurer alternative to Traditional Medicare (Part C). Plans are paid a fixed, risk-adjusted amount per enrollee — which rewards documenting more diagnoses (upcoding), the central source of overpayment. plan, Medicaid managed care plan, and federal ACA Marketplace insurer had to post how often it denied prior authorizationPrior AuthorizationA health-insurance process that requires your doctor to get advance approval from your plan before it will cover a specific service, procedure, or drug. requests in 2025, and how often those denials were reversed on appeal. The first reports went up by March 31, 2026.
This page is about care refused before it happens. Every figure is the insurer's own reported number, or a federal dataset, as analyzed by KFF.
17%
of standard Medicare Advantage requests denied by UnitedHealth Group in 2025
All 6 MA insurers analyzed: 12%
21%
of standard ACA Marketplace requests denied by UnitedHealth Group in 2025
All 8 Marketplace insurers analyzed: 18%
2 in 3
appealed Medicare Advantage denials were reversed in 2025 (67%)
The denial didn't hold up once challenged
Section I · Insurer-Reported, 2025
The First Public Numbers
The CMS Interoperability and Prior Authorization Final Rule (CMS-0057-F), finalized in 2024, requires covered insurers to post their prior authorization metrics on their public websites every year. The first reports, covering 2025, were due March 31, 2026. In August 2026, KFF analyzed reports from 14 insurers covering about 71 million people.
Share of standard requests denied, 2025
| Market (2025) | Standard denied | Expedited denied | Approved on appeal | Median decision |
|---|---|---|---|---|
| Medicare Advantage | 12% | 10% | 67% | ~1 day |
| Medicaid managed care | 14% | 12% | 47% | ~1 day |
| ACA Marketplace | 18% | 16% | 43% | ~1 day |
Averages across the insurers KFF analyzed: 6 in Medicare Advantage (~69% of MA enrollees), 8 in Medicaid managed care (~54%), and 8 on the federal Marketplace (~74%). "Approved on appeal" is the share of appealed standard denials that were reversed.
The number to remember
In Medicare Advantage, two out of three denials that patients or doctors appealed were reversed. The care was approved in the end, after a delay the patient had to fight through. Most denials are never appealed at all.
Section II · By Company
By Insurer — What KFF Reported
KFF's analysis names the highest and lowest rates in each market and calls out notable insurers. It doesn't print every company's figure, so this table shows only what KFF reported. KFF reports at the parent-company level: "UnitedHealth Group" includes UnitedHealthcare.
| Insurer | Market | 2025 figure |
|---|---|---|
| UnitedHealth Group | Medicare Advantage | 17% standard denied (market: 12%) |
| UnitedHealth Group | ACA Marketplace | 21% standard denied (market: 18%) |
| UnitedHealth Group | Medicaid managed care | 11% denied; 81% of appealed denials reversed, the highest of the Medicaid insurers analyzed |
| Centene | ACA Marketplace | 25% standard denied, the highest; 54% reversed on appeal |
| Centene | Medicare Advantage | 93% of appealed denials reversed |
| Independence Health Group | Medicaid managed care | 23% standard denied, the highest |
| Elevance Health | Medicare Advantage | 5% standard denied |
| Kaiser Permanente | Medicare Advantage | 40% of appealed denials reversed |
| CVS Health (Aetna) | Medicaid managed care | 22% of appealed denials reversed |
| GuideWell | ACA Marketplace | 3% standard denied, the lowest |
| L.A. Care Health Plan | Medicaid managed care | 2% standard denied, the lowest |
Source: KFF, "Prior Authorization Metrics Provide New Insights into Insurer Practices, but Gaps Remain" (Aug. 13, 2026), analyzing insurers' 2025 reports posted under CMS-0057-F.
Section III · Federal Data, 2023–2024
The Medicare Advantage Track Record
Before insurers had to post their own numbers, CMS collected Medicare Advantage prior authorization data through its plan reporting. KFF analyzed it for 2023 and 2024. In 2024, Medicare Advantage insurers made 52.8 million prior authorization decisions and denied 4.1 million (7.7%). Only 11.5% of denials were appealed, and 80.7% of those appeals succeeded.
| Insurer (2024) | Denied | Denials appealed | Appeals reversed |
|---|---|---|---|
| UnitedHealthcare | 12.8% | 11.9% | 79.1% |
| Centene | 12.3% | 7.6% | 95.5% |
| CVS (Aetna) | 11.9% | 19.9% | 92.6% |
| Kaiser Permanente | 10.9% | 1.6% | 51.0% |
| Humana | 5.8% | 10.5% | 64.7% |
| Elevance Health | 4.2% | 7.4% | 86.5% |
| Other insurers | 5.5% | 10.2% | 78.1% |
| All Medicare Advantage | 7.7% | 11.5% | 80.7% |
UnitedHealthcare had the highest denial rate of any major Medicare Advantage insurer in 2024, up from 9.1% in 2023. The insurer-published 2025 figure is 17%.
Don't line these up as a trend
The 2023–2024 figures come from CMS's plan reporting. The 2025 figures come from each insurer's own posted report, under different definitions (the 2025 rates are for "standard" requests). Both show UnitedHealth above the market. But a jump from 12.8% to 17% may be partly a change in how it's counted, so we don't present it as a one-year increase.
Denials that broke Medicare's own rules
Medicare Advantage plans don't get to write their own coverage rules. They're paid with federal money under a contract with CMS that requires them to cover everything original Medicare covers, under the same written coverage policies: National and Local Coverage Determinations. Those aren't loose "medical norms." They spell out exactly when care must be covered, and a plan that denies care meeting them is breaking the terms it's paid to follow.
The government checked. In 2022, the HHS Office of Inspector General reviewed prior authorization denials from 15 of the largest Medicare Advantage companies and found that 13% met Medicare's coverage rules. Original Medicare would likely have approved them. Plans had applied clinical criteria that aren't in Medicare's rules, like requiring an x-ray before an MRI, or claimed the records were insufficient when reviewers found them adequate. On the payment side, 18% of denied payments met Medicare and billing rules.
Apply 13% to the 4.1 million Medicare Advantage denials in 2024 and it would mean roughly half a million denials of care Medicare's own rules cover, in one year. That's our arithmetic, not an OIG finding: the OIG's sample was from 2019.
Since January 2024, CMS's rule CMS-4201-F says this outright: Medicare Advantage plans can't use internal criteria stricter than original Medicare's where Medicare's rules are already spelled out. The rule restated an obligation the plans already had.
Source: HHS-OIG, "Some Medicare Advantage Organization Denials of Prior Authorization Requests Raise Concerns About Beneficiary Access to Medically Necessary Care" (OEI-09-18-00260, April 2022). Sample: 250 prior authorization and 250 payment denials issued June 1–7, 2019.
Source: KFF, "Medicare Advantage Insurers Made Nearly 53 Million Prior Authorization Determinations in 2024," analyzing CMS Part C reporting data. Fuller 2023 and 2024 detail, with archived copies, is on our denial rates data explorer.
On the Record · January 22, 2026
"Only about less than 2% of all the interactions that we receive are under a prior authorization review. And the vast majority of those are administrative. And at the end of the day, 99% of all the care is covered."
— Stephen Hemsley, CEO, UnitedHealth Group, to the House Energy & Commerce Committee, 2:22:23
Our read: "99% of all the care" counts every routine visit, refill and lab test. The 2% that goes through prior authorization is where the expensive, high-stakes care sits: prosthetics, cancer drugs, wound grafts, surgeries. Being in the 2% is where people lose limbs and savings.
"Our read" is AbilityForge's analysis, not reported fact. Later in the same hearing he gave "less than 2%" as his denial rate; see that exchange.
Section IV · Limits of the Data
What the Reports Leave Out
Publishing is a real step. But the rule left the format and the detail up to the insurers, and KFF found the reports hard to use. These are the gaps KFF named:
Percentages, no counts
You see "17% denied" but not 17% of how many requests, so you can't judge scale.
No breakdown by service
One number covers everything from MRIs to prosthetic legs. A patient can't see how their kind of care fares.
No reasons
Appeal results aren't broken out by service or by why the request was denied.
Averages hide the waits
Decision times are medians or averages. No ranges, and no count of decisions that missed the deadline.
No standard format
CMS's template is optional. Formats and units differ, some report nationally instead of by state, and the reports are hard to find.
Employer plans aren't covered
The rule covers Medicare Advantage, Medicaid, CHIP and the federal Marketplace. Employer plans, which cover most working Americans, publish no prior authorization data.
Prescription drugs are excluded too. The metrics cover medical items and services only.
Section V · AbilityForge Policy Position
Our Position: A Denial Facts Label
Every gap above is a choice the rule left to insurers. Other industries already have the fix: one required format, the same for every seller, so a buyer can compare.
Nutrition Facts
Required by federal law since 1990. Same panel on every package.
Broadband labels
Since 2024, the FCC requires internet providers to show price and speed in one standard label.
Health insurance already does it
The ACA's Summary of Benefits and Coverage is a required, standard-format sheet. The industry complies for benefits. It just isn't required for denials.
Denial Facts
[Insurer] · [Plan type] · [State] · [Year]
Denied, by type of care
Same format for every plan, posted in the same place, filed with one federal lookup. A proposal by AbilityForge.
What the label would fix
- Counts beside percentages, so scale is visible.
- Denials by type of care, so an amputee can see how prosthetic requests fare, and a cancer patient can see imaging.
- Top denial reasons and outside-review results, so a denial pattern can't hide in an average.
- Late decisions counted, not averaged away.
- One mandatory format, one location, and a single federal lookup site.
- Every plan, including employer plans. Reaching most employer plans would take a change to federal law, likely ERISA, the law that governs them.
The point is informed purchasing. People compare plans on premiums and deductibles because those are posted in a standard form. Whether a plan pays when you need it is the one thing you can't compare.
Common Ground
The White House's January 2026 "Great Healthcare Plan" calls for insurers to publish claim denial and appeal data in plain English. That's the core of the Denial Facts idea. It's an outline, not yet a bill. We'd like to see Congress write this part into law, whoever's name is on it. AJMC summary →
This section is AbilityForge's policy proposal, not reported fact. No bill currently requires this label.
Section VI
Questions People Ask
What is a prior authorization denial rate?
The share of requests for advance approval that an insurer turns down. Your doctor asks the plan to approve a test, procedure or device before it happens; a denial means the plan won't cover it unless the decision is reversed. It's different from a claim denial, which happens after care. Claim denial rates are here.
Which insurer denies the most prior authorizations?
It depends on the market. In KFF's analysis of 2025 reports, Centene had the highest ACA Marketplace rate (25%), Independence Health Group the highest Medicaid managed care rate (23%), and UnitedHealth Group denied 17% of standard Medicare Advantage requests against a 12% average. In 2024 federal Medicare Advantage data, UnitedHealthcare had the highest rate of the major insurers, 12.8%.
Do insurers have to publish their prior authorization data?
Some do. Under CMS-0057-F, Medicare Advantage plans, Medicaid and CHIP plans, and insurers on the federal ACA Marketplace must post yearly metrics on their websites, starting with 2025 data by March 31, 2026. Employer plans are not covered.
Should I appeal a prior authorization denial?
The data says appeals often work. In 2025, 67% of appealed Medicare Advantage denials were reversed, and in 2024 federal data it was 80.7%. Yet only about 1 in 9 Medicare Advantage denials is appealed. Since January 1, 2026, plans covered by the rule must give a specific reason for every prior authorization denial, which is your starting point for the appeal.
Sources
- KFF, "Prior Authorization Metrics Provide New Insights into Insurer Practices, but Gaps Remain" (Aug. 13, 2026). Michelle Long, Jeannie Fuglesten Biniek, Justin Lo, Rayna Wallace, Jada Raphael, Allison Kim, Kaye Pestaina.
- KFF, "Medicare Advantage Insurers Made Nearly 53 Million Prior Authorization Determinations in 2024" (archived copy).
- CMS, Interoperability and Prior Authorization Final Rule (CMS-0057-F) fact sheet.