While it varies by data source and year, UnitedHealthcare (UHC) and Blue Cross Blue Shield of Alabama frequently appear among insurers with the highest claim denial rates (around 33-35% in 2023 for Marketplace plans), alongside companies like AvMed, Molina Healthcare, and Health Care Service Corporation, though the absolute "most" depends on the specific dataset, like marketplace vs. employer plans, with some insurers having significantly lower rates.
In 2023, roughly one third of all in-network claims made to AvMed were denied by the medical insurance company. In this year, AvMed and United HealthCare were the medical insurance companies with the highest denial rate for in-network claims in the United States, at 33 percent each.
Claim not filed on time (aka: Timely Filing)
If a proper claim is submitted, but it's not within the timing window, it may result in a denial. It is recommended that you check with your Payers regarding their filing deadlines.
A rejected claim is typically the result of: A coding error(s), • A mismatched procedure and ICD-10 code(s), or • A terminated patient medical insurance policy.
Top 10 Denials in Medical Billing
Denial Code CO-97 is used in medical billing to indicate that a claim has been denied because the billed service is considered part of another service that has already been processed.
The 80/20 rule in insurance refers to two main concepts: the Medical Loss Ratio (MLR) under the Affordable Care Act (ACA), requiring insurers to spend 80% (85% for large groups) of premiums on care or refund the rest, and a common home insurance clause where you must insure your home for at least 80% of its replacement cost to receive full coverage for partial losses, preventing underinsurance. In health insurance, it limits administrative costs and profits, while in homeowners insurance, it ensures adequate dwelling coverage to avoid penalties on claims.
Kaiser Permanente has the lowest claim denial rate among major health insurance companies, which the analysis defined as brands offering Marketplace plans in seven states or more during the 2025 plan year. The California-based healthcare company denied just 6% of claims based on the available 2023 data.
If a service or product that you received wasn't covered and you disagree, here are a few errors that may cause the claim denial.
The most frequent home insurance claims are caused by wind and hail damage, followed by water damage and fires. Fires are the most expensive cause of loss for homeowners, resulting in the highest average claim amount.
Which Insurance Companies Are Considered The Worst?
New India Assurance boasts the lowest claim rejection rate at 0.2%, outperforming all other insurers in India, according to a recent report.
Top reasons for healthcare claim denials include missing or inaccurate data, lack of prior authorizations, and incomplete patient registration. Discover how automation and artificial intelligence (AI) can help healthcare organizations overcome these roadblocks and break the denial cycle.
Coverage limits of $250,000 / $500,000 (often written as 250/500) mean your auto liability insurance pays up to $250,000 for bodily injury to one person and up to $500,000 total for all people injured in a single accident, with a third number (e.g., $100,000) usually covering property damage (e.g., 250/500/100). This is a "split limit" policy, defining maximum payouts for specific injury/damage categories, leaving you personally liable for costs exceeding these amounts.
Inadequate documentation of medical necessity: Payers may deny claims with code 40 if there is inadequate documentation of the medical necessity of the services provided. Providers should ensure that their documentation clearly supports the medical necessity of the services and includes relevant clinical information.
The denial code CO23 surfaces in healthcare billing systems as a coordination issue between multiple insurance providers. This code indicates that the impact of prior payer adjudication, including payments and adjustments, has affected the current claim's processing.