Which Insurance Company Denies the Most Prior Authorizations? (2025 Data)

For the first time ever, health insurers are required to publicly report how often they deny prior authorization requests. Under CMS's Interoperability and Prior Authorization Final Rule (CMS-0057-F), insurers had to post their calendar year 2025 data on their websites by March 31, 2026. We reviewed the filings from the nation's largest insurers. The results confirm what patients and doctors have long suspected: denial rates vary wildly by insurer, and most denials are beatable on appeal.

The Bottom Line

Over 80% of prior authorization appeals are overturned — yet only about 12% of patients ever appeal. If your prior authorization is denied, appeal it. The data shows your odds of winning are excellent. See our step-by-step PA appeal guide for exactly how.

Why CY2025 Numbers Look Better Than CY2024

You may notice that some CY2025 denial rates appear dramatically lower than older CMS data (e.g., UHC went from 12.6% to 4.6% for Medicare Advantage). This is largely a methodology difference, not an actual improvement. Under CMS-0057-F, insurers self-report and many count cases "approved after appeal" as approved — which lowers the headline denial rate. CMS's prior methodology counted initial denials regardless of appeal outcome. When comparing numbers across years, be aware that how "approved" is defined can dramatically change the figures. We note the data year for every number in this article.

The Comparison: Denial Rates by Insurer (CY2025)

This table is sourced directly from each insurer's own CMS-0057-F filing — not from any third-party aggregator. We reviewed the public filings from six of the nation's largest insurers.

Insurer	Plan Type	Std. Denied	Exp. Denied	Appeals Overturned	Avg TAT
Cigna	ACA Marketplace	27%	22%	16%	3.95 days
Ambetter (Centene)	ACA Marketplace (FL)	21%	20.38%	58.23%	4 days
UnitedHealthcare	ACA Marketplace	19.7%	—	—	24 hrs
Humana	Medicaid (KY)	12.79%	2.13%	29.16%	1 day
UnitedHealthcare	Employer & Individual	11.5%	—	—	24 hrs
Anthem (Elevance)	Medicaid (VA)	11.1%	7.0%	28.3%	3 days
UnitedHealthcare	Medicaid	8.5%	—	—	24 hrs
Humana	Medicare Advantage	6.17%	9.36%	67.02%	1 day
Anthem (Elevance)	Medicaid (IN)	5.3%	10.2%	42.2%	1 day
UnitedHealthcare	Medicare Advantage	4.6%	—	—	24 hrs
Aetna (CVS Health)	Medicare Advantage	2.39%	2.94%	53.33%	3.06 days

All data sourced directly from each insurer's CMS-0057-F filing, Jan 1 – Dec 31, 2025. Sorted by standard denial rate (highest first). "Avg TAT" = average turnaround time. UHC's figures include post-appeal approvals, which may lower their reported denial rate vs. other insurers. See methodology for details on each insurer's reporting.

Key Findings From the Data

Medicaid members face 2x higher denial rates than MA members at the same insurer. Humana denies 12.79% for Kentucky Medicaid vs. 6.17% for Medicare Advantage — and Medicaid appeals succeed only 29% of the time vs. 67% for MA. See the data.
Some insurers deny urgent requests MORE often than standard ones. Anthem Indiana denies expedited (urgent) PA requests at nearly double the rate of standard requests (10.2% vs. 5.3%). See the data.
97% of denied patients don't appeal — but 67% of those who do, win. Humana had 17,287 denials but only 467 appeals. Of those, 313 were overturned. An estimated 11,000+ patients accepted beatable denials. See the data.
Cigna denies 27% of ACA marketplace requests — the highest rate we found — with only a 16% appeal overturn rate. Ambetter and UHC also deny roughly 1 in 5 marketplace requests.

What Insurers Must Now Disclose

CMS-0057-F requires MA, Medicaid, and ACA marketplace insurers to publicly post eight categories of PA data every year — including approval/denial rates, appeal outcomes, expedited request data, and average turnaround times. This is the first year this disclosure has been mandated.

Insurer-by-Insurer Detail

The comparison table above shows the full picture. Below are brief notes on each insurer's CY2025 filing, including what they reported, how to find it, and what stands out.

UnitedHealthcare

The nation's largest insurer published a detailed transparency page with data across all plan types. Their headline "91.7% approved" masks huge variation: Medicare Advantage members see a 4.6% denial rate while ACA marketplace members face 19.7% — more than four times higher. UHC counts post-appeal approvals in their "approved" figure, which partially explains why their CY2025 MA rate (4.6%) looks much better than CMS's CY2024 figure (12.6%).

Cigna

Cigna's IFP FFE disclosure covers ACA marketplace plans only and reveals the highest denial rate we found: 27% of standard requests denied, with only 16% of appeals overturned. Unlike most insurers where appeals routinely succeed, Cigna denials largely stick — making strong clinical documentation critical from the start.

Ambetter (Centene)

Ambetter's Florida filing (Issuer ID 49004) processed 419,452 standard PA requests — a massive volume that makes this data statistically robust. They denied 21% of standard requests, but unlike Cigna, 58% of appeals were overturned. If your Ambetter plan denies a PA, appealing is strongly worth it.

Aetna (CVS Health)

Aetna's Medicare Advantage filing (Contract H0523) shows the lowest denial rate we found: 2.39% standard, 2.94% expedited. A second contract (H0562) reported 100% approval with zero denials. When denials do occur, 53% are overturned on appeal.

Humana

Humana published contract-level MA reports showing a 6.17% standard denial rate with a strong 67% appeal overturn rate and a fast 5-hour average expedited turnaround. Their Kentucky Medicaid data tells a different story — 12.79% denied with only 29% appeal success. See the Medicaid gap below.

Anthem (Elevance Health)

Anthem published state-level Medicaid scorecards showing significant variation: Indiana at 5.3% denied with 42% appeal success vs. Virginia at 11.1% denied with only 28% appeal success. Notably, Anthem Indiana denies expedited requests at nearly double the standard rate (10.2% vs. 5.3%) — see the expedited paradox below.

The Medicaid Gap: Higher Denials, Lower Appeal Success

One of the most troubling patterns in the CY2025 data is the disparity between plan typeswithin the same insurer. Medicaid enrollees — by definition lower-income — face both higher denial rates and lower appeal success rates:

Insurer	Plan Type	Std. Denied	Appeals Overturned
Humana	Medicare Advantage (H4461)	6.17%	67.02%
Humana	Medicaid (KY)	12.79%	29.16%
Anthem	Medicaid (IN)	5.3%	42.2%
Anthem	Medicaid (VA)	11.1%	28.3%

Source: Insurer CMS-0057-F filings, CY2025. Same insurer, different plan types, different outcomes.

Humana's Kentucky Medicaid members are denied at twice the rate of their Medicare Advantage members (12.79% vs. 6.17%) — and when they appeal, they win less than half as often (29% vs. 67%). The Trump administration's June 2025 decision to suspend CMS's health equity reporting requirements means this disparity will not be tracked at the demographic level — making data like this more important.

The Expedited Denial Paradox

You might expect urgent PA requests — filed when a patient's health is at immediate risk — would be approved more often. The CY2025 data shows the opposite at some insurers:

Insurer	Std. Denied	Exp. Denied	Gap
Anthem IN (Medicaid)	5.3%	10.2%	+4.9 pts
Humana H4461 (MA)	6.17%	9.36%	+3.2 pts
Ambetter FL (ACA)	21.0%	20.38%	−0.6 pts
Cigna (ACA)	27%	22%	−5 pts
Anthem VA (Medicaid)	11.1%	7.0%	−4.1 pts

Source: Insurer CMS-0057-F filings, CY2025. Positive gap = expedited denied MORE often than standard.

Anthem Indiana denies expedited requests at nearly double the rate of standard ones. If your urgent PA is denied, don't assume it was a well-considered clinical decision — the data suggests expedited reviews may receive less thorough evaluation, not more.

Why Most Patients Leave Healthcare on the Table

The appeal overturn rate is the most actionable number in these reports. When over 80% of appeals succeed, it means most initial denials don't hold up. But the CY2025 filings reveal exactly how few patients fight back:

Insurer	Std. Denials	Appeals Filed	Appeal Rate	Appeals Won
Ambetter FL	88,079	3,670	4.2%	58.2%
Humana H4461 (MA)	17,287	467	2.7%	67.0%
Humana H5525 (MA)	21,438	565	2.6%	67.1%

Source: Insurer CMS-0057-F filings, CY2025. "Appeal Rate" = appeals filed ÷ total standard denials.

The Math That Should Change Your Mind

Humana denied 17,287 standard PA requests under contract H4461. Only 467 patients appealed — just 2.7%. Of those 467 appeals, 313 were overturned (67%). That means roughly 11,282 patients accepted denials they likely could have overturned, simply by filing an appeal. If you're one of the 97% who doesn't appeal — the data says you're leaving your healthcare on the table.

The Trend: Denials Are Rising (2019–2024)

Despite insurer pledges to streamline prior authorization, total PA volume in Medicare Advantage has grown 42% since 2019 and denial rates have trended upward:

Year	Total PA Requests	Denial Rate	Appeals Overturned
2019	37.1M	5.7%	75.0%
2020	35.0M	5.6%	74.6%
2021	37.9M	5.8%	82.3%
2022	46.7M	7.4%	82.0%
2023	49.8M	6.4%	81.7%
2024	52.8M	7.7%	80.7%

Source: CMS Medicare Advantage prior authorization data, 2019–2024 (analyzed by KFF). Denial rates are for medical services (excluding Part D drugs).

How to Look Up Your Insurer's Report

Under CMS-0057-F, every MA, Medicaid, and ACA marketplace insurer must post their PA metrics publicly. Here's where to find them:

Where to Find Your Insurer's CMS-0057-F Report

UnitedHealthcare: uhc.com/legal/cms-interoperability-prior-authorization
Cigna: cigna.com/legal/compliance/disclosures
Aetna: aetna.com/health-care-professionals/prior-authorization-statistics.html
Anthem (Elevance): State-specific scorecards via anthem.com provider portal
All other insurers: Search your insurer's website for "prior authorization metrics" or "CMS interoperability." If you can't find it, call member services and ask for their CMS-0057-F prior authorization disclosure.

What to Do If Your Prior Authorization Is Denied

Your PA Denial Action Plan

Read the denial letter carefully — under the 2026 CMS rule, insurers must provide specific clinical reasons for every denial
Ask your doctor for a peer-to-peer review — a phone call with the insurer's medical director often resolves denials before a formal appeal
File a formal internal appeal with clinical documentation, published guidelines, and a letter of medical necessity from your doctor
Request an external review if the internal appeal fails — this is an independent review at no cost to you, and the decision is binding
Reference your insurer's overturn data in your appeal: "According to CMS data, [Insurer] overturns [X]% of PA denials on appeal, indicating a pattern of initial denials that do not withstand scrutiny."

For detailed step-by-step instructions, see our complete prior authorization appeal guide. For help with the bills that result from delayed or denied care, you can upload your medical bill to check for billing errors and generate professional appeal letters.

Methodology

This article presents original research. We reviewed the CMS-0057-F prior authorization transparency filings published directly by each insurer on their public websites, covering calendar year 2025 (January 1 – December 31, 2025). We extracted data from UnitedHealthcare, Cigna, Ambetter/Centene, Humana, Aetna, and Anthem/Elevance — covering Medicare Advantage, Medicaid, and ACA marketplace plan types across multiple states.

Data methodology varies between insurers. UnitedHealthcare counts cases "approved after appeal" as approved in their headline figures, which lowers their reported denial rate compared to CMS's methodology (which counts initial denials). Cigna's report covers only their IFP FFE (ACA marketplace) plans. Anthem reports at the state level for Medicaid. Humana reports at the MA contract level. Ambetter reports at the issuer level per state. We note these differences throughout the article and show the plan type for each data point in our comparison table.

Historical trend data (2019–2024) uses CMS aggregate Medicare Advantage data. This article is updated annually when new CY data becomes available. Last updated: April 2026.

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Content is for informational purposes only and does not constitute financial, legal, or medical advice. Consult a qualified professional for advice specific to your situation.