ACA Marketplace Plans See Highest Denial Rate in Nine Years

HFMA reported that ACA marketplace plans reached their highest denial rate since the marketplace launched in 2014, with insurers denying approximately 20 percent of all submitted claims. This milestone arrives at a time when marketplace enrollment has surged to over 24 million Americans, meaning more patients than ever are enrolled in plans that deny one in five claims. For physician practices serving marketplace patients, this is not a statistical abstraction — it is an operational reality that demands attention.

A 20 percent denial rate means that for every five claims a practice submits to a marketplace insurer, one is expected to come back denied. At that rate, denial management is not an occasional inconvenience — it is a core business function that directly impacts practice viability.

The Scale of the Problem

With 24 million enrollees, ACA marketplace plans represent a significant and growing segment of the commercially insured population. Many physician practices, particularly those in primary care, family medicine, and mental health, serve substantial numbers of marketplace patients. The 20 percent denial rate across this population translates to millions of denied claims annually.

The denial rate has climbed steadily since the marketplace's early years. In the first years of marketplace operation, denial rates were lower as insurers built their networks and established their claims processing systems. The upward trend since then suggests that marketplace insurers have become more aggressive in claims adjudication — using tighter medical necessity criteria, more extensive claims editing, and broader application of prior authorization requirements.

Why Marketplace Denial Rates Are Higher

Several factors contribute to the elevated denial rates in marketplace plans compared to employer-sponsored insurance:

• Narrow networks. Marketplace plans frequently use narrow provider networks to keep premiums competitive. Services rendered by out-of-network providers — sometimes inadvertently — face significantly higher denial rates, with out-of-network denial rates reported at 37 percent.
• Cost management pressure. Marketplace insurers operate on thin margins and face competitive pressure to keep premiums low. Aggressive claims management, including higher denial rates, is one mechanism for controlling costs.
• Prior authorization expansion. Marketplace plans have expanded PA requirements to cover a broader range of services, creating more opportunities for claims to be denied for failure to obtain authorization or for not meeting PA criteria.
• Plan design complexity. The variety of marketplace plan tiers (Bronze, Silver, Gold, Platinum) creates complexity in determining what is covered, at what level, and under what conditions — complexity that can produce denials based on plan-specific limitations that practices may not be aware of at the time of service.

The Appeal Gap

Perhaps the most troubling statistic associated with marketplace denials is the appeal rate. KFF data shows that fewer than 0.2 percent of marketplace denials are appealed internally. This means that for every 1,000 denied claims, fewer than two are contested through the payer's internal appeal process.

The reasons for the low appeal rate are multiple: patients may not understand their appeal rights, practices may lack the staff resources to prepare appeals, the dollar amount of individual denied claims may not justify the cost of appeal preparation, and the timelines for filing appeals may pass before the denial is identified and reviewed.

But the data on appeal success rates — when appeals are filed, a meaningful percentage are overturned — suggests that the low appeal rate represents a significant missed revenue recovery opportunity. Practices leaving marketplace denials uncontested are leaving money on the table.

What Physician Practices Should Do

The nine-year-high denial rate for marketplace plans requires a strategic response from physician practices:

Verify eligibility and benefits before rendering services to marketplace patients. Understanding the patient's specific plan design, network restrictions, and PA requirements before the encounter reduces the risk of preventable denials.

Track denial rates by marketplace plan. Not all marketplace insurers deny at the same rate. Identifying which plans have the highest denial rates allows practices to allocate denial management resources more effectively and to make informed decisions about plan participation.

Build appeal workflows that can handle the volume. With a 20 percent denial rate, a practice seeing 100 marketplace patients per week can expect 20 denied claims. If even half of those denials are clinically contestable, that is 10 appeals per week — a workload that requires dedicated processes and potentially dedicated staff.

A 20 percent denial rate that goes uncontested is a 20 percent revenue loss. A 20 percent denial rate that is systematically appealed becomes a recoverable challenge. The difference is operational capacity and commitment.