Best Health Insurance Plans for Appeals: Which Insurers Have the Best Appeal Success Rates

Most health insurance buyers focus on premium cost, network breadth, and prescription drug coverage when choosing a plan. Few people think about what happens when coverage is denied — and which insurers are most likely to overturn that denial on appeal.

But for the 17–20% of insurance claims that get denied, the appeal success rate may matter more than the premium. This guide looks at what the data says about which insurers are more receptive to appeals — and which ones fight the hardest against reversal.

Why Appeal Success Rate Matters

A claim denial is not always final. Most health insurance denials can be appealed — first internally (to the insurer's own review team) and then externally (to an IROs) Explained" class="auto-link">independent review organization or state agency). External appeal overturn rates measure how often independent reviewers disagree with the insurer and rule in the patient's favor.

High external appeal overturn rates mean one of two things (or both):

1. The insurer is denying claims it should approve — triggering reversals at appeal.
2. The insurer's clinical criteria are more restrictive than accepted medical standards.

Either way, a high overturn rate is a yellow flag for potential enrollees.

ACA Marketplace External Appeal Data

For ACA marketplace plans, CMS collects data on internal and external appeals. External appeals in ACA plans go to independent review organizations (IROs) designated by the state or by CMS.

Industry-wide, approximately 40–50% of external appeals in ACA marketplace plans are decided in the enrollee's favor — meaning nearly half the time an independent reviewer looks at a denial, they say the insurer was wrong.

Insurers with historically better internal appeal overturn rates:

• Plans affiliated with Kaiser Permanente show lower rates of external appeals being filed in the first place — a signal that more denials are reversed internally or that fewer inappropriate denials are issued.
• Some smaller regional BCBS plans show strong internal appeal processes.

Insurers with lower internal overturn rates (where more members need to escalate to External Independent Review: Complete Guide" class="auto-link">external review):

• Large national commercial insurers with high volume and automated review processes.
• Plans using AI-assisted or bulk-review PA processes.

Medicare Advantage Appeal Overturn Rates

The Medicare Advantage appeal data is among the most detailed available. At the Qualified Independent Contractor (QIC) level — the first external review step in MA appeals — historical data has shown overturn rates ranging from 30% to over 75% depending on the plan and service type.

Key observation: Plans with high PA Denial Rates by Insurer (2026)" class="auto-link">denial rates also tend to have higher QIC overturn rates. This pattern suggests systematic over-denial — issuing denials that cannot survive independent scrutiny.

CMS uses internal quality assurance programs and annual audits to track MA plan performance on coverage determinations. Plans with persistent overturn problems receive compliance letters and corrective action requirements.

What Makes an Insurer More Receptive to Appeals?

Several structural factors make some insurers more likely to reverse denials on appeal:

1. Integrated Care Models

Kaiser Permanente's integrated structure — where physicians and the insurance plan are the same organization — means clinical decisions have more weight in coverage determinations from the beginning. When an appeal is filed internally, it is reviewed by physicians in the same organization who understand the clinical context.

2. Non-Profit Status and Community Mission

Non-profit health plans (some BCBS licensees, regional cooperatives) face different incentive structures than publicly traded insurers. Profit pressure is less acute, which can reduce the tendency to systematically deny borderline claims for financial reasons.

3. Strong Internal Review Culture

Some plans invest in qualified clinical reviewers for appeals who have genuine authority to reverse initial decisions. Others route all appeals to the same administrative staff who handled the initial denial — with predictable results.

4. Regulatory Environment

Insurers operating in states with strong insurance commissioner oversight, mandatory external review, and aggressive enforcement tend to issue fewer inappropriate denials because the reversal cost (and reputational cost) is real.

California, New York, and Washington have particularly active insurance regulation; plans operating in those states face more accountability than in states with lighter oversight.

Characteristics of Plans to Avoid

Warning signs that a plan may fight hard against valid appeals:

• Consistently high Prior Authorization Denied: How to Appeal" class="auto-link">prior authorization denial rates in publicly available data.
• High complaint ratios in NAIC data.
• Low Medical Loss Ratio (near the ACA minimum) indicating aggressive claims management.
• History of regulatory sanctions for coverage determination violations.
• Use of automated bulk-review systems for PA (documented at some large insurers).

Practical Buyer's Guide

When evaluating health plans — especially during open enrollment — consider these steps:

1. Check CMS marketplace denial rate data (available at data.cms.gov for ACA plans).
2. Review NAIC complaint ratios for the specific insurer entity.
3. Look up Medicare Advantage star ratings if considering an MA plan (medicare.gov/plan-compare).
4. Check your state insurance department's annual report for plan-specific complaint and denial data.
5. Ask your employer's benefits team if your employer plan publishes appeal outcome data (many large self-funded plans do not, but it does not hurt to ask).

The Appeal Process Is the Equalizer

The good news: even with insurers that issue frequent denials, the external appeal process is genuinely independent and often favorable to members. The law requires:

• Timely internal reviews.
• Independent external review access.
• Written decisions with specific clinical criteria cited.

These requirements create real accountability. An insurer that cannot justify its denial to an independent reviewer will lose — and must pay.

Fight Back With ClaimBack

Whatever insurer denied your claim, ClaimBack helps you build the strongest possible appeal — organizing your medical documentation, addressing the specific denial criteria, and navigating the external review process.

Start your appeal at ClaimBack

Related Reading

• How to Write an Insurance Appeal Letter
• Internal vs. External Insurance Appeals
• Common Reasons Insurance Claims Are Denied