Ever wondered which health insurance company denies the most claims? It’s actually UnitedHealthcare — rejecting a staggering one-third (33%) of in-network claims. That’s not just slightly above average — it’s nearly double the overall marketplace plan denial rate of 19%.
If you’ve ever had a claim denied, you’re definitely not alone. The frustration of fighting with insurance companies after receiving healthcare is something millions of Americans experience each year. Meanwhile, Kaiser Permanente stands out as the best major health insurance company for paying claims, with only 6% of medical bills denied. However, the quality gap between insurance providers is enormous — some insurers deny as little as 1% of claims while others reject up to 54% of in-network claims.
What’s even more concerning? Fewer than 1% of denied claims are ever appealed, despite insurance companies overturning their original decision 44% of the time when challenged. In this article, I’ll walk you through the seven worst health insurance companies for claim denials in 2025 — no complicated jargon, just straightforward facts to help you avoid potential headaches down the road.
UnitedHealthcare
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“UnitedHealthcare has a 56.4% denial rate, compared with the industry standard of 5% to 10%” — OHSU Spokeswoman, Official representative of Oregon Health & Science University
UnitedHealthcare tops the list as America’s largest health insurer—and unfortunately, also leads in claim denials. According to multiple studies, this insurance giant systematically rejects a significantly higher percentage of claims than most competitors.
UnitedHealthcare denial rate in 2025
The reality of UnitedHealthcare’s denial rate differs dramatically depending on who you ask. The insurer itself claims to approve 90% of claims shortly after submission, with the remaining 10% undergoing additional review. UnitedHealthcare further asserts that after this review process, their approval rate reaches 98% for eligible members when claims are submitted properly.
Nevertheless, independent analyzes tell a starkly different story. A careful examination of Centers for Medicare & Medicaid Services (CMS) data revealed that UnitedHealthcare denied claims at approximately 33%—the highest rate among major insurers. Even more concerning, Oregon Health & Science University (OHSU) reported that UnitedHealthcare maintains a 56.4% denial rate, substantially exceeding the industry standard of 5% to 10%.
Furthermore, the denial pattern shows troubling growth in specific healthcare areas. Between 2019 and 2022, UnitedHealthcare’s post-acute services denial rate soared from 8.7% to 22.7%. During this same period, their skilled nursing home denial rate increased ninefold, coinciding with the company’s implementation of NaviHealth-backed nH Predict, an algorithmic tool used for claims management.
Common denial reasons by UnitedHealthcare
UnitedHealthcare rejects claims for several recurring reasons:
- Eligibility verification issues – Often occurs when patients recently switched plans but didn’t share current health plan ID cards with providers
- Duplicate submissions – When providers inadvertently submit multiple claims for the same service
- Incomplete documentation – Missing information necessary for claim review
- Coverage limitations – Services not included in the specific plan by the employer, CMS, or state government
- Clinical guidelines non-compliance – Treatment not aligning with evidence-based standards (reportedly only affecting about 0.5% of claims)
Technical issues also trigger denials, particularly unregistered taxonomy codes and incorrect service location information. According to UnitedHealthcare, most denials stem from benefit criteria issues rather than clinical decisions.
Appeal success rate for UnitedHealthcare claims
Remarkably, challenging UnitedHealthcare’s denials frequently succeeds—yet few patients pursue this option. Research demonstrates that over 80% of appealed prior authorization denials are decided in patients’ favor. Accordingly, a class action lawsuit filed against UnitedHealthcare alleged that more than 90% of denials are reversed through internal appeals or proceedings before federal administrative law judges.
Despite these favorable odds, Americans file formal appeals on merely 0.1% of claims denied under the Affordable Care Act. Many patients don’t pursue appeals because they’re unaware of their rights (45%), uncertain whom to contact (40%), or simply don’t have time to navigate the process (nearly 25%).
Consumer complaints and issues with UnitedHealthcare
Patients dealing with UnitedHealthcare face substantial difficulties beyond initial denials. The insurer takes an average of 307.3 days to resolve claims—the longest resolution time among all insurance companies that OHSU does business with. Additionally, UnitedHealthcare accounts for 48% of all peer-to-peer denials at OHSU.
The consequences extend beyond financial burdens to actual healthcare outcomes. Approximately one-quarter of consumers with denied claims experience significant delays in receiving medical care, with about the same proportion unable to receive care altogether. Consequently, around one-quarter reported their health declined due to these delays.
Mental health suffers too. Roughly 80% of adults reported they or a family member experienced worry or anxiety about care delays resulting from coverage denials. Many patients find themselves caught in a distressing cycle of denials, appeals, and uncertainty—all while their health conditions potentially worsen.
The transparency issue compounds these problems, as insurers frequently cite “other” as the most common denial reason. This vague designation makes it exceptionally difficult for patients to understand why their claims were rejected or how to address the underlying issues.
Elevance Health (Anthem)
Elevance Health (formerly known as Anthem) ranks as the second-worst major insurer for claim denials in 2025. The insurance giant operates through multiple Blue Cross Blue Shield affiliates across the country, covering millions of Americans while maintaining troublingly high rejection rates.
Elevance Health claim denial statistics
Elevance Health denies a substantial 23% of in-network claims, placing it among the most rejection-prone insurers in the healthcare marketplace. This means nearly one in four valid in-network medical claims submitted to Elevance gets rejected—significantly higher than the national average of 19% for marketplace plans. Specifically, this high denial rate applies across 154 Elevance Health plans operating in seven states.
For perspective, while Elevance’s 23% denial rate is concerning, it remains below UnitedHealthcare’s industry-leading 33% rejection rate. Nevertheless, Elevance processes approximately 40 million claims monthly, meaning roughly 9.2 million claims face denial each month based on their rejection percentage.
At the state level, denial rates vary dramatically. In fact, Elevance’s Blues plan in Alabama has the highest state average in-network denial rate at 34%, reflecting substantial regional variations in how the company handles claims.
Top reasons for denied claims by Elevance
Like most insurers, Elevance Health denies claims for several common reasons. Based on available data across marketplace plans, the denial reasons typically include:
- “Other” unspecified reasons (34% of denials)
- Administrative issues (18% of denials)
- Excluded services (16% of denials)
- Exceeding benefit limits (12% of denials)
- Lack of prior authorization or referral (9% of denials)
- Medical necessity determinations (6% of denials)
The high percentage of “other” reasons makes it particularly difficult for consumers to understand why their claims were rejected. Moreover, Elevance has been subject to formal complaints regarding unlawful denial patterns. In California, for instance, the California Medical Association filed a complaint asserting that Anthem Blue Cross (part of Elevance) has adopted policies under which it “routinely denies claims that include high level emergency department evaluation and management services”.
Appeal outcomes for Elevance Health
Unfortunately, most consumers never challenge Elevance’s claim denials. Records show patients appeal only about 1% of denied in-network claims, despite having the legal right to contest rejections. Subsequently, when consumers do appeal, Elevance upholds approximately 56% of their original denial decisions.
The appeal process generally requires submitting an application form with supporting information, including policy details, healthcare provider information, service dates, claim numbers, and relevant medical documentation. Following submission, an administrative panel not involved in the initial decision reviews the appeal, typically rendering a decision within 30 days.
When internal appeals fail, consumers have the option for external review through independent medical bodies. Nonetheless, many patients remain unaware of these rights—indeed, a Kaiser Family Foundation survey found that only 40% of consumers knew they had legal rights to appeal to a government agency or independent medical expert.
Elevance Health consumer satisfaction
In spite of high denial rates, Elevance Health has worked to improve consumer experience, specifically through technological solutions. The company has implemented a self-service claim denial review system that uses predictive analytics to provide real-time feedback on why claims were denied. This digital portal aims to streamline inquiries by reason codes, allowing providers to understand denial reasons within minutes rather than waiting for explanation of benefits documents.
These efforts appear to have yielded positive results in some areas. A consumer satisfaction report found Elevance Health (as Anthem) scored 75 out of 100 in overall customer satisfaction—tying for the highest score among health insurers and representing a 9% improvement over the previous year. Additionally, Elevance has achieved greater efficiency in claims processing, resulting in faster reimbursement for approved claims.
Yet challenges remain, particularly for those whose claims are denied. Patient advocacy groups have highlighted that the “cumbersome and opaque appeals process” creates significant barriers for consumers trying to get coverage for essential care. As Elevance continues evolving its practices, millions of members still face the frustration of navigating these high denial rates.
Molina Healthcare
Securing the third spot on our list, Molina Healthcare demonstrates an alarming pattern of claim denials that affects millions of members nationwide. This insurer, which primarily serves Medicaid and marketplace enrollees, has caught regulatory attention for its high rejection rates.
Molina Healthcare denial rate overview
Molina Healthcare holds the distinction of having the highest overall denial rate among major Medicaid insurers at 17.7%. This figure substantially exceeds the industry average and places Molina above other major players like CareSource (15.4%) and UnitedHealthcare (13.6%).
The situation becomes even more concerning when examining individual state plans. Seven of Molina’s 12 managed care organizations, representing approximately 1.2 million enrollees, have denial rates exceeding 25%. Most notably, Molina’s Illinois plan rejected an extraordinary 41.4% of claims—the single highest denial rate among all insurers reviewed. Similarly troubling, their Texas plan denied 34.2% of claims, earning it the second-highest rejection rate nationally.
Beyond Medicaid, across all insurance markets, Molina reportedly denies about 26% of claims, positioning it consistently among the worst performers for claim approvals.
Frequent causes of claim denials by Molina
According to Molina’s own documentation, several recurring issues trigger claim denials:
- Missing Explanation of Benefits (EOB) from primary insurers when members have other coverage
- Incomplete or invalid EOB information submitted with claims
- Exact/duplicate claim submissions for previously processed services
- Missing or incomplete claim information, particularly when submitting corrected claims
- Expired timely filing windows for claim submission
- Missing or invalid condition codes required for specific services
- Invalid ordering/referring provider NPIs that don’t match physician records
A concerning pattern emerges from Molina’s own reports, which document numerous “Claims Payment Systemic Errors” (CPSEs) affecting their processing systems. In 2025 alone, Molina acknowledged multiple technical issues causing improper denials, including incorrectly denying claims with coordination of benefits and failing to properly review claims with attachments prior to adjudication.
Appeal process effectiveness at Molina
Molina’s appeal process typically gives members 60-90 calendar days from the denial date to file an appeal, depending on the state and plan type. Once submitted, Molina generally acknowledges receipt within 3-5 business days and renders decisions within 14-30 calendar days.
Notably, members seeking continued coverage during the appeal must file within 10 business days of the denial notification, creating a tight window for action during medical crises.
While specific success rates for Molina appeals aren’t publicly disclosed, consumer experiences suggest mixed outcomes. Troublingly, one user reported that Molina “denied all claims when primary insurance is commercial” and “denied all of my appeals,” forcing them to stop accepting Medicaid clients.
The appeal pathway includes multiple potential stages—internal review, state administrative hearing, independent review, and board of appeals—though few patients navigate beyond the initial stages.
Molina Healthcare consumer reviews
Consumer experiences with Molina often highlight frustration with claim processing and appeals. One member described needing state insurance commissioner intervention after Molina denied cancer medication twice and then assigned an Independent Review Organization (IRO) without notification.
Others report specific service categories facing systematic denials, including:
- ABA therapy services for patients with commercial primary insurance
- Biological infusions for chronic conditions
- Mobility aids like wheelchairs
- Physical therapy services
The recurring pattern involves initial denials followed by challenging appeal experiences, often requiring external intervention to resolve. As one consumer noted, only after involving regulatory authorities did Molina “reluctantly approve” their medication.
The impact extends beyond financial concerns—many patients report treatment delays or complete inability to access needed care until claims are resolved, directly affecting health outcomes and quality of life.
Health Care Service Corporation (HCSC)
“The number of denied claims in 2022 was nine times higher compared to 2019” — U.S. Senate Permanent Subcommittee on Investigations, Democratic members of a Senate oversight subcommittee
With more than 17 million members across five states, Health Care Service Corporation (HCSC) stands as the fourth-largest health insurer in the United States. Yet, behind this impressive scale lies a troubling pattern of claim denials that affects countless patients seeking care.
HCSC claim denial rate in 2025
Data from the Kaiser Family Foundation reveals HCSC denied an alarming 29% of in-network claims across its 915 plans operating in four states. This rate positions HCSC as the third-highest among major insurers for claim denials, trailing only UnitedHealthcare (33%) and Blue Cross Blue Shield of Alabama (35%). Essentially, this means nearly one in three valid medical claims submitted to HCSC faces rejection—substantially exceeding the marketplace average of 19%.
In practice, HCSC processes millions of claims monthly, resulting in hundreds of thousands of denials. Apparently, although the insurer states that “most claims are approved”, the nearly one-third rejection rate contradicts this reassurance and creates significant barriers for patients seeking coverage.
Why HCSC denies claims
HCSC’s denials predominantly stem from several recurring issues:
- Minor data errors in claim submissions (the most common reason for denials)
- Services provided by out-of-network providers
- Treatments requiring prior authorization that wasn’t obtained
- Procedures excluded from specific plan coverage
- Clinical determinations that services weren’t medically necessary
- Experimental treatments without proven effectiveness
- Claims inadvertently sent to the wrong insurance entity
Fundamentally, HCSC—like other major insurers—often cites an ambiguous “other” reason for denials, accounting for approximately 34% of all rejections. This vague categorization typically makes it difficult for members to understand and address the actual causes behind their denied claims.
Appeal success rate for HCSC
Challenging HCSC’s claim denials can be remarkably effective, yet few members pursue this option. Broadly speaking, across all insurers, 80% of appeals result in successful reversals of initial denial decisions. Regardless, only about 1% of denied claims are formally appealed, leaving countless legitimate claims uncontested.
HCSC offers an internal appeals process for members to challenge denials, outlined in their “adverse benefit determination” section of policy booklets. Afterward, if the internal appeal is denied, members sometimes qualify for external review by independent entities, particularly for denials related to medical necessity or clinically unproven services.
Typically, when consumers do appeal, insurers uphold about 56% of their original denials, suggesting that a significant portion of appeals (44%) succeed in overturning initial decisions.
HCSC consumer experience
HCSC members facing claim denials report considerable difficulties navigating their coverage. Among consumers with denied claims, 65% struggle to understand what their insurance covers, 57% are confused about out-of-pocket costs, and 52% find explanation of benefits statements perplexing.
Concurrently, only 29% of those with denied claims report satisfactory resolution of their insurance problems, compared to 59% satisfaction among those whose issues don’t involve claim denials. Although 84% of consumers with denied claims take some action to resolve their insurance problems, most (69%) remain unaware of their appeal rights.
The consequences extend beyond financial strain. Undeniably, patients with denied claims experience delayed care, leading to worsening health conditions and unexpected higher out-of-pocket expenses. This creates a challenging cycle where administrative decisions directly impact health outcomes and financial security for HCSC members.
Blue Cross Blue Shield of Alabama
Among all major insurers nationwide, Blue Cross Blue Shield of Alabama stands out with the highest claim denial rate in the country, creating significant challenges for its members seeking care.
Denial rate for BCBS Alabama
First and foremost, BCBS Alabama rejects an extraordinary 35% of in-network claims, ranking it as the insurer with the highest denial rate among large payers in the United States. This means more than one-third of all valid medical claims submitted to BCBS Alabama face rejection—substantially exceeding the marketplace average of 19%. In practical terms, for every three claims submitted by patients or providers, BCBS Alabama denies at least one.
Surprisingly, this high denial rate applies across all 12 BCBS Alabama plans operating in the state. Some critics have suggested this pattern represents a systematic approach rather than isolated incidents. As an illustration, one Forbes analysis questioned whether “BCBS is leveraging prior authorization as a cost-control mechanism” since approximately one-third of physician-led treatment decisions face denial.
Common denial reasons by BCBS Alabama
Similar to other insurers, BCBS Alabama rejects claims for several recurring reasons. The most common explanation falls under a vague “other” category, accounting for 34% of denials. In addition to this ambiguous classification, denials often involve:
- Excluded services (16% of denials)
- Lack of prior authorization or referral (9% of denials)
- Medical necessity determinations (6% of denials)
Consumer reports indicate specific issues with routine medical services being denied. For instance, one member reported BCBS Alabama denied bloodwork performed during an annual physical—care typically covered under the Affordable Care Act. As a result, patients often face unexpected bills for preventive services that should be covered.
Appeal outcomes for BCBS Alabama
BCBS Alabama provides members with appeal rights, yet few utilize this option. As a general trend, only about 1% of denied in-network claims are formally appealed. When consumers do challenge denials, BCBS Alabama upholds approximately 56% of their original decisions.
The appeal process requires submitting documentation explaining the disagreement, including supporting materials like physician letters and medical records. Members have the right to appoint an authorized representative to handle the appeal process on their behalf, which can be valuable given the complexity of the system.
Consumer feedback on BCBS Alabama
Consumer experiences with BCBS Alabama often highlight frustration with claim processing. Multiple members report having to fight denials that should have been covered, such as strep throat lab work and routine physical bloodwork. Equally important, patients note that BCBS Alabama “doesn’t have a patient advocate or any mechanism to escalate a complaint”, creating additional barriers for those seeking resolution.
Some consumers express concern about BCBS Alabama’s business practices. In one case, a patient who received only partial reimbursement for a preventive vaccination—despite the service being listed as fully covered in their benefits plan—expressed disappointment that BCBS “doesn’t abide by their Standard Benefit Plan”.
Sendero Health Plans
Texas-based Sendero Health Plans claims the sixth position on our list with a troubling record of denying more than one in four claims submitted by its members and healthcare providers.
Sendero Health Plans denial statistics
Sendero Health Plans maintains a 28% denial rate, placing it firmly among insurers with the highest rejection rates nationwide. This regional insurer serves over 20,000 members yet denies more than a quarter of all claims submitted—substantially higher than what many consider acceptable industry standards.
Top denial reasons from Sendero
A Texas Department of Insurance examination revealed several concerning patterns in Sendero’s claim handling. In 27% of cases, Sendero issued adverse determinations without giving providers reasonable opportunity to discuss treatment. Additionally, the company failed to provide required documentation lists in 29% of appeals and missed deadlines for expedited prescription drug appeals at the same rate.
Even more alarming, 83% of oral adverse determination appeals lacked the required one-page appeal form, while 17% of processed claims had inadequate explanation of payments.
Sendero appeal process and success rate
Sendero offers a structured yet complex two-tier appeal system. Members must file Level I Appeal Reconsiderations within 120 calendar days of initial denial, including a completed claim form, explanation of payment copy, written explanation, and supporting documentation.
Should this first appeal fail, members have just 30 calendar days to file a Level II Appeal. Only after exhausting these internal processes can members file complaints with the Texas Department of Insurance.
Consumer issues with Sendero Health Plans
Consumer feedback paints a bleak picture of Sendero’s customer service. One Google reviewer awarded Sendero a single star, calling even this low rating “too generous”. Common complaints include:
- Phones consistently going unanswered
- Emails receiving no response
- Providers unable to verify active coverage despite members presenting valid insurance cards
As one frustrated former member noted, these issues ultimately forced him to “switch back to UnitedHealthcare, even though my premiums increased significantly”—a telling indication of the service quality problems that compound Sendero’s high denial rates.
AvMed
Florida-based AvMed rounds out our list as the seventh-worst insurer for claim denials in 2025, tying for the highest rejection rate among major health insurance providers nationwide.
AvMed claim denial rate in 2025
AvMed rejects an alarming 33% of in-network claims submitted by members and providers, matching UnitedHealthcare for the highest denial rate among major insurers. This means one in three valid medical claims faces rejection—significantly higher than the industry average. With approximately 1.2 million members, this high denial percentage affects hundreds of thousands of patients annually seeking coverage for legitimate medical expenses.
Why AvMed denies claims
Unlike larger insurers, AvMed doesn’t publicly disclose specific reasons for their high denial rates. Nevertheless, based on industry patterns, denials typically fall into several categories including coding errors, missing information, lack of prior authorization, and services deemed not medically necessary. The company’s official documentation shows they have established claims processing procedures, yet the exceptionally high rejection rate raises questions about their approval criteria and administrative practices.
Appeal success rate for AvMed
AvMed maintains a formal appeals system for its 23,958 Medicare Advantage members. Their process defines a level 1 appeal as “a formal request for AvMed to review AvMed’s decision not to pay for, not to provide, or to stop an item or service that a member believes they need”. Members can appeal decisions to deny specialist visits, physical therapy, or claim payments. Unfortunately, specific success rates for these appeals aren’t publicly disclosed, making it difficult for consumers to gage their chances of overturning denials.
AvMed consumer complaints
Consumer satisfaction with AvMed appears extraordinarily low, with just 1.6 stars on Google reviews. Numerous reviewers stated they would give “zero stars” if possible. Given its position among insurers with the highest denial rates, alongside poor customer reviews, AvMed presents significant challenges for members seeking reliable coverage. CEO Larry Schreiber faces mounting criticism as customers express frustration with claim handling and customer service issues.
Comparison Table
| Insurance Company | Overall Denial Rate | Main Reasons for Denials | Appeal Rate | Notable Consumer Issues |
|---|---|---|---|---|
| UnitedHealthcare | 33-56.4% | Eligibility verification, Duplicate submissions, Incomplete documentation, Coverage limitations | 0.1% of denied claims | Average 307.3 days to resolve claims; 48% of peer-to-peer denials at OHSU |
| Elevance Health (Anthem) | 23% | “Other” (34%), Administrative issues (18%), Excluded services (16%) | 1% of denied claims | Cumbersome appeals process; High state-level variations (up to 34% in Alabama) |
| Molina Healthcare | 17.7-41.4% | Missing EOB, Incomplete information, Expired filing windows, Invalid condition codes | Not mentioned | Systematic denials of specific services; Multiple technical system errors reported |
| HCSC | 29% | “Other” (34%), Minor data errors, Out-of-network services | 1% of denied claims | 65% of members struggle to understand coverage; 57% confused about costs |
| BCBS Alabama | 35% | “Other” (34%), Excluded services (16%), Lack of authorization (9%) | 1% of denied claims | No patient advocate system; Issues with routine preventive care coverage |
| Sendero Health Plans | 28% | Missing documentation, Inadequate payment explanations | Not mentioned | Poor customer service; Consistent communication issues |
| AvMed | 33% | Not specifically detailed in article | Not mentioned | 1.6/5 stars customer rating; Significant customer service complaints |
Conclusion
After examining the seven worst offenders for health insurance claim denials, a troubling pattern emerges. Major insurers systematically reject a significant portion of legitimate claims, with denial rates ranging from 17.7% to a staggering 56.4%. UnitedHealthcare leads this concerning trend, denying one-third of in-network claims—nearly double the marketplace average.
Perhaps most alarming, these companies frequently cite vague “other” reasons for denials, making it exceptionally difficult for patients to understand why their coverage was rejected. Additionally, less than 1% of denied claims ever face formal appeals, despite evidence showing that 44-80% of challenges result in overturned decisions.
The consequences extend far beyond financial strain. Patients with denied claims experience significant delays in care, with approximately one-quarter reporting their health declined while fighting insurance battles. Meanwhile, 65% struggle to understand what their insurance actually covers, creating a perfect storm of confusion and inadequate care.
This data paints a clear picture: health insurance companies benefit when patients remain unaware of their appeal rights or feel too overwhelmed to challenge denials. Nevertheless, your best defense against unfair denials remains understanding your appeal options and persistently advocating for your rightful coverage.
Though fighting against insurance giants might seem daunting, remember that Kaiser Permanente stands out as a positive exception, denying only 6% of claims. This stark contrast undoubtedly demonstrates that better practices exist—consumers simply need to demand them from all insurers.
FAQs
Q1. What is the average claim denial rate for health insurance companies in 2025? The average claim denial rate for marketplace health insurance plans is about 19%. However, some major insurers like UnitedHealthcare have much higher rates, denying up to 33-56% of in-network claims.
Q2. Why do health insurance companies deny claims so frequently? Common reasons for claim denials include eligibility issues, incomplete documentation, lack of prior authorization, services deemed not medically necessary, and coding errors. Many insurers also cite vague “other” reasons, making it difficult for patients to understand the exact cause.
Q3. How often do patients appeal denied claims? Despite having the right to appeal, less than 1% of denied claims are formally appealed by patients. This low appeal rate persists even though 44-80% of appeals result in overturned decisions.
Q4. What impact do claim denials have on patients’ health? Claim denials can significantly impact patient health. About 25% of patients with denied claims experience delays in receiving medical care, with a similar percentage reporting their health declined while fighting insurance battles.
Q5. Are there any health insurance companies with low denial rates? Yes, while many major insurers have high denial rates, some perform better. For example, Kaiser Permanente stands out with only a 6% denial rate, demonstrating that lower denial rates are possible in the industry.
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