A self-funded health plan claims audit is an independent review of paid medical claims that verifies payment accuracy, confirms contract compliance and recovers overpayments. ERISA Section 404 places this oversight duty on the plan sponsor, not the TPA. Most plans review fewer than 5% of claims, leaving the rest unchecked.
A 1,400-employee manufacturer ran its first independent claims audit eighteen months into a new TPA relationship. The review found more than $800,000 in overpayments, including one inpatient claim paid twice and a specialty drug billed well above the contracted rate. None of it had appeared in the TPA's own accuracy reporting.
That gap is not unusual. Industry benchmarks put administrator error rates at 1% to 3% of total claims processed, and most self-funded plans independently review only a small slice of what gets paid. Sixty-seven percent of covered workers, including 80% at large employers, are now enrolled in self-funded plans according to KFF's 2025 Employer Health Benefits Survey, which means the unreviewed portion represents real money moving through systems almost nobody independently checks.
What a Claims Audit Actually Verifies
A claims audit is an independent, line-by-line review of paid medical claims against plan documents, contracted rates and coding rules. Most employers assume this already happens because their TPA reports a high accuracy score every quarter. That figure is usually self-reported and calculated against the TPA's own sample, not an outside standard.
The reality looks different once someone outside the TPA checks the work. Most self-funded employer health plans review fewer than 5% of claims, typically through a stratified sample the TPA selects and grades itself. Grading your own homework produces a different number than an outside reviewer checking the same file.
An audit is not an accusation. It is closer to a financial reconciliation: matching what the plan document promises, what the contract with the provider specifies and what actually got paid.
Audit frequency compounds the problem. It is common for employers to run a full claims audit or provider billing review only once every three years, according to Baker Tilly's analysis of self-funded plan billing reviews. Between those audits, errors accumulate quietly and rarely show up in a quarterly dashboard.
Why the Oversight Gap Exists
The gap exists because TPAs are not the ones bearing financial risk when a claim gets paid wrong. The plan sponsor pays the claim either way, so the administrator has limited financial incentive to catch every error before it goes out the door. That is a structural fact of the outsourcing arrangement, not a statement about any single TPA's intent.
Audit frequency compounds the problem. It is common for employers to run a full claims audit or provider billing review only once every three years, according to Baker Tilly's analysis of self-funded plan billing reviews. Between those audits, errors accumulate quietly and rarely show up in a quarterly dashboard.
Contract language plays a role too. Some administrative services agreements historically limited how many claims a sponsor could audit, who could perform the audit or what data the auditor could access, which narrowed what oversight was even possible.
The Real Cost of an Unreviewed Plan
Unreviewed claims translate directly into dollars the plan never should have paid. Industry benchmarks estimate payment errors typically affect 1% to 3% of total claims dollars, and some comprehensive independent audits identify a wider range depending on plan complexity and TPA type. On a plan paying $20 million a year in claims, even the low end of that range is $200,000 sitting unrecovered.
Think of it like a bank account that is never properly checked. A small error might not seem like much on one transaction, but when thousands of transactions have small errors, the total can become huge.
That is what happens with many healthcare audit findings. It is usually not one big fraud. It is thousands of small errors that nobody was checking for.
The average family health insurance premium is now $26,993. Employers and employees share this cost. When an audit finds and recovers money that was paid incorrectly, that money can help reduce future healthcare costs instead of forcing employers to raise premiums or cut benefits.
What's Actually Happening Behind the Scenes
Coding and Billing Errors
Upcoding, unbundling and duplicate billing are the most common findings in independent audits. A procedure billed at a higher-complexity code than performed, or a bundled service billed as separate line items, both inflate the paid amount without an obvious red flag in a summary report.
Coordination of Benefits Gaps
When a member has coverage under more than one plan, claims should be split according to coordination of benefits rules. Gaps here mean the self-funded plan sometimes pays a share that another payer should have covered.
Why Current Approaches Aren't Enough
Relying solely on the TPA's own reporting leaves the plan sponsor with an incomplete picture, because the reviewer and the reviewed party are the same entity. The table below lays out the practical difference between the status quo and an independent oversight model.
How to Fix It
Red Flags That Signal Your Plan Needs This Now
The ROI of Doing It Right
A comprehensive independent claims audit typically recovers 1% to 3% of annual claims spend in its first year, often more than covering the cost of the audit itself. On a plan spending $30 million annually, that is a recovery range of $300,000 to $900,000 before counting the value of catching future errors sooner.
The fiduciary protection matters as much as the dollar recovery. DOL/EBSA recovered $1.4 billion in FY 2025 and closed 878 civil investigations, with 63% producing monetary or corrective results, and the agency has signaled health plan oversight is a growing FY 2026 focus. A documented, independent audit process is the evidence a plan sponsor needs if that scrutiny ever reaches their plan.
Litigation risk reinforces the same point. Plaintiff firms that spent two decades pursuing excessive-fee claims against 401(k) plans have expanded into health plan cases, including Lewandowski v. Johnson & Johnson and Navarro v. Wells Fargo, both alleging fiduciaries failed to prudently monitor PBM and administrative costs. An audit trail is the difference between a defensible process and an unmonitored one.
Conclusion and Next Steps
Every dollar a self-funded plan pays out should be able to withstand a question: was this claim reviewed, is the payment justified, and can the plan sponsor defend it if asked. Right now, most plans cannot answer that question for the majority of what they pay, because the only review happening is the one the TPA runs on itself.
The fix does not require replacing your TPA relationship. It requires adding an independent layer of oversight, documenting the process, and treating claims accuracy as a fiduciary obligation rather than an assumption. Schedule a claims audit scoping call to see what an independent review would find on your plan.
Frequently Asked Questions
What is a self-funded health plan claims audit?
An independent review of paid claims that checks payment accuracy against plan terms, contracted rates and coding rules.
Who is legally responsible for claims accuracy under ERISA?
The plan sponsor, under the fiduciary duty in ERISA Section 404, not the TPA that processes the claims.
How often should a self-funded plan be audited?
Every twelve to eighteen months, with ongoing quarterly or monthly spot reviews between full audits.
What percentage of claims does a typical TPA review internally?
A stratified sample, usually 250 to 400 claims, far short of the full claims population.
How much money does an independent audit typically recover?
About 1% to 3% of annual claims spend in the first year, based on industry benchmarks.
Can a TPA restrict how a plan sponsor audits its own claims?
Some contracts historically limited audit scope or auditor choice; sponsors should negotiate these restrictions out.
Does an audit create legal protection for plan fiduciaries?
Yes. Documented, independent review is core evidence of the prudent process ERISA requires.
What is the difference between a claims audit and dependent eligibility review?
A claims audit checks payment accuracy; a dependent eligibility review confirms covered dependents still qualify for the plan.
