For millions of families in the United States, having health insurance no longer provides peace of mind. Sometimes it doesn’t even guarantee care. In 2026, the real fear begins after leaving the hospital: opening the mail to find that the insurer has denied the claim.
The problem is no longer isolated. The latest federal data show that nearly 20% of medical claims are denied in the U.S. health care system. Behind that figure are halted treatments, postponed surgeries, and bills capable of destabilizing any family budget.
And yes, some companies keep turning up on lists of the biggest denials.
Which insurers deny the most medical claims?
Analyses based on federal HealthCare.gov data place several insurers under increasing scrutiny.
Among the most named is Oscar Health. Some reports show that certain plans from the company rejected roughly a quarter of claims within the network. Consumers and patient advocates have criticized opaque approval processes and restrictions on access to specialists.
Another recurring name is UnitedHealthcare. The company has faced questions over the use of automated systems and prior authorizations that, critics say, delay treatments and increase denials in certain medical categories.
Elevance Health, the parent company of Anthem, also figures. Some of its plans exceeded denial rates of 20%, especially in reviews related to coverage and reimbursements.
In the case of Aetna, owned by CVS Health, analysts detected elevated percentages of denials tied to specialty care and out-of-network services.
Meanwhile, Molina Healthcare also appeared among the companies with the highest denial rates. The concern here is twofold: many of its members belong to low-income communities or rely on government programs.
The quiet problem: almost no one appeals
There is one finding that worries more than the denials themselves. Most patients never appeal.
Although many claims could be reversed after a formal review, experts say consumers tend to give up before starting the process. Endless forms, technical language, and a lack of knowledge about rights end up working in the insurers’ favor.
In other words: many companies know that administrative wear-and-tear works.
Why are medical insurance denials rising?
The system has become more complex. Prior authorizations, coverage limits, and internal rules change constantly. And as medical costs continue to rise, insurers tighten filters to contain expenses.
That is transforming the way Americans choose health coverage. It’s no longer enough to compare low monthly premiums. More and more consumers research approval statistics before signing up for a plan.
Because cheap insurance loses its meaning if it ends up denying essential procedures when they are most needed.
What can consumers do before buying insurance
Experts recommend carefully reviewing claim histories, verifying in-network doctors, and understanding prior authorization rules before signing any policy.
For more official information about consumer rights and coverage, visit HealthCare.gov.
