What Is a Third Party Administrator (TPA)? An Employer's Guide

What a third party administrator actually does

If you run a self-funded or level-funded health plan, the third party administrator is the company doing most of the day-to-day work you never see. They process claims, manage eligibility, run the member service line, handle appeals, and keep the paperwork compliant. They are not your insurance company. They do not take on the financial risk of your plan. They run the machinery.

That distinction matters more than it sounds, and in 2026 it matters in ways it never did before. A pair of federal court rulings has started to redraw the line on what a TPA is legally responsible for, and the Department of Labor has proposed rules that would force TPAs to disclose far more about how they make money off your plan. If you employ a high-turnover hourly workforce, where administration is the hard part and margins are thin, understanding this relationship is no longer optional.

Here is the plain-English version of what a TPA is, how it differs from a carrier and an ASO arrangement, and what to actually look for when you pick one.

The five jobs every TPA owns

A third party administrator handles the operational functions of a health plan on the employer's behalf. The work breaks down into five buckets:

A TPA does all of this without ever owning the risk. The money paying those claims is yours. That single fact is the key to understanding everything else about how TPAs differ from the alternatives.

TPA vs. carrier: who is actually holding the risk

A traditional insurance carrier sells you a fully insured plan. You pay a fixed premium, and the carrier takes on the risk. If claims come in higher than expected, that is the carrier's problem. If they come in lower, the carrier keeps the difference. You have handed off both the administration and the financial exposure in one package.

A TPA does the opposite on the risk side. In a self-funded plan you pay claims as they happen out of your own funds, usually backed by a stop-loss policy that caps your downside. The TPA administers the plan, but the financial risk stays with you. No premium, no risk transfer, no carrier keeping the spread. You pay the TPA a flat per-employee-per-month administrative fee and you keep control of plan design.

The trade is control for responsibility. With a carrier you get simplicity and a fixed cost. With a TPA you get the ability to tailor benefit levels, networks, and formulary design to your actual workforce, plus visibility into where every dollar goes. For an employer whose claims are predictable and whose workforce has specific needs, that control is worth a lot.

TPA vs. ASO: the distinction that trips up most employers

This is the one almost everyone gets wrong, so it is worth slowing down.

ASO stands for Administrative Services Only. It describes the arrangement, not the company. An ASO arrangement means the employer self-funds the claims and outsources the administration to a partner. That partner can be an independent TPA, or it can be the administrative arm of a big-name carrier offering "self-funding through us."

So the real comparison is not TPA versus ASO. It is independent TPA versus carrier-run ASO. And the difference is independence.

A carrier-run ASO shares the carrier's name, staff, network, and incentives. It is convenient, and the brand on the ID card reassures employees. But you are tied to that carrier's network, its pricing, and its way of doing things. An independent TPA works with whatever vendors fit your plan: it can shop networks, swap pharmacy benefit managers, and bolt on point solutions without asking a parent company for permission. That flexibility is the whole reason independent TPAs exist.

Why self-funded and level-funded plans need a TPA

The moment you stop buying a fully insured product and start funding your own claims, someone has to do the administrative work the carrier used to bundle in. That someone is the TPA. There is no self-funded or level-funded plan without one, because the employer is not equipped to adjudicate claims, run a member service line, or produce stop-loss reporting in house.

Level-funded plans, which have become the on-ramp to self-funding for smaller employers, lean even harder on the TPA. The whole appeal of level funding is predictable monthly costs with a year-end refund if claims run low. Delivering that requires tight claims administration and clean reporting, both of which sit with the TPA.

Where TPAs fit for high-turnover, hourly workforces

For staffing agencies, restaurants, construction firms, and other employers of hourly workers, the administration is the entire problem. The coverage is straightforward. Many of these employers use a MEC plan to meet the ACA's §4980H(a) coverage mandate and avoid the no-coverage "sledgehammer" penalty. (MEC alone satisfies §4980H(a); it does not provide minimum value, so it does not eliminate the separate §4980H(b) penalty.) What is hard is tracking eligibility across a roster that churns every month, enforcing the ACA's measurement and stability periods, and filing accurate 1095-Cs for hundreds of employees who cycled on and off the plan during the year.

A good TPA, or a platform that handles administration end to end, absorbs that complexity. A bad one passes it back to your HR team in the form of re-keyed census data, missed eligibility windows, and 1095-C corrections in March. When you employ a variable-hour workforce, the quality of your administration is the quality of your benefits program. The plan document barely matters by comparison.

The 2026 fiduciary shift every employer should understand

For decades, TPAs operated on a simple legal premise: they were administrators, not fiduciaries. They followed the plan document, processed what they were told to process, and pointed to their service contracts as proof they had no discretionary authority over the plan. That shield is cracking.

In May 2025 the Sixth Circuit Court of Appeals, in Tiara Yachts v. Blue Cross Blue Shield of Michigan, reversed a lower court and held that a TPA's role in processing claims and profiting from overpayments could give rise to fiduciary responsibility under ERISA. The court rejected the argument that a service contract alone shields a TPA from fiduciary liability. Around the same time, employers like Aramark sued their administrators (in Aramark's case, Aetna) alleging breached fiduciary duties, improper claims approvals, and commingling of plan funds.

Regulators are pushing in the same direction on transparency. A Department of Labor rule proposed on January 30, 2026, under ERISA §408(b)(2), would require pharmacy benefit managers, along with the TPAs that contract with self-funded plans to provide PBM services, to disclose their compensation in detail, and the Consolidated Appropriations Act, 2026 added further PBM-transparency reforms. The throughline is the same: you are expected to know how the vendors running your plan get paid and to act on it.

The practical takeaway is not to panic. It is to ask harder questions, get fee disclosures in writing, and choose an administrator whose compensation is fully visible. Which brings us to selection.

How to choose a TPA

Use this as a screening checklist when you evaluate administrators or platforms:

What a TPA costs

TPA pricing is typically a per-employee-per-month (PEPM) administrative fee, separate from the claims dollars and the stop-loss premium. PEPM fees vary widely based on the services bundled in and the size of your group, and the headline number is not the whole cost. The hidden costs live in network spread, PBM arrangements, and add-on fees, which is exactly what the 2026 disclosure rules are designed to surface.

The right way to compare is total cost of administration plus expected claims plus stop-loss, with every fee disclosed, against a fully insured premium for equivalent coverage. For many employers with a stable or predictable claims profile, the self-funded-plus-TPA route comes out ahead while handing back control of the plan. For employers who would rather not manage any of it, a platform that combines coverage and administration in one place removes the question entirely.