An ASO, or administrative services only arrangement, is a setup where an employer pays for employee health claims directly out of its own funds but hires an outside company to handle the paperwork. Instead of buying a traditional insurance policy, the employer essentially becomes its own insurer and contracts with a third party (often a well-known insurance company) to process claims, manage provider networks, and handle day-to-day plan administration.
How an ASO Works
In a standard, fully insured health plan, an employer pays a fixed monthly premium to an insurance company. That insurer then covers employee medical bills as they come in. The insurer takes on the financial risk: if claims are higher than expected, the insurer absorbs the cost. If claims are low, the insurer keeps the difference.
An ASO flips this model. The employer sets aside its own money to pay medical claims as employees incur them. There’s no fixed monthly premium going to an insurer. Instead, the employer pays a much smaller administrative fee to a third-party administrator (TPA) for services like processing claims, issuing payments, managing enrollment, and giving employees access to a network of doctors and hospitals. Many large insurers like Blue Cross Blue Shield, UnitedHealthcare, and Cigna offer ASO services to employers who want to self-fund but still need the infrastructure of a major insurance operation.
From the employee’s perspective, an ASO plan often looks identical to traditional insurance. You get an insurance card, use in-network providers, and file claims the same way. The difference is behind the scenes: your employer, not an insurance company, is the one actually paying your medical bills.
Why Employers Choose ASO Plans
Cost control is the primary driver. With a fully insured plan, the employer pays a premium that includes the insurer’s profit margin, administrative overhead, and a buffer for risk. With an ASO, the employer removes that markup and pays only for actual claims plus a smaller admin fee. In years when employees are relatively healthy and claims are low, the employer keeps the savings rather than padding an insurer’s bottom line.
ASO arrangements also give employers more flexibility in plan design. Fully insured plans come with standardized benefit structures largely dictated by the insurance carrier. Self-funded employers using an ASO can customize coverage, adjust deductibles, and tailor wellness programs to their specific workforce. They also get direct access to claims data, which helps them identify health trends among employees and target interventions more precisely.
There’s a regulatory advantage too. Self-funded plans are governed by a federal law called ERISA, which generally preempts state insurance regulations. This means a company with employees in multiple states can offer a single, uniform benefits plan rather than navigating different state mandates in each location.
The Financial Risk Trade-Off
The flip side of those savings is exposure. Because the employer is paying claims directly, a year with unexpectedly high medical costs can hit the budget hard. A single employee with a serious illness or injury could generate hundreds of thousands of dollars in claims.
To manage this risk, most employers with ASO arrangements purchase stop-loss insurance. This is a separate policy that kicks in when claims exceed a certain threshold, either for a single individual (called specific stop-loss) or for the group as a whole (called aggregate stop-loss). Aggregate stop-loss limits a company’s total liability from overall claim fluctuations in a given year. Think of it as a safety net that caps the employer’s worst-case scenario while still allowing them to benefit from lower-than-expected claims in good years.
How Common Are ASO Plans?
Self-funded arrangements administered through ASOs are far more common than most people realize. According to a 2025 report from the U.S. Department of Labor, roughly 79 percent of participants in large employer health plans were covered by some form of self-insurance in 2022. Across the broader market, approximately 48,700 self-insured group health plans covered nearly 39 million participants directly, with another 30 million covered through mixed-insured plans that combine self-funded and fully insured components.
The model skews heavily toward larger employers. While only 46 percent of large plans were self- or mixed-insured, those plans covered the vast majority of workers in that size category. Smaller companies are less likely to self-fund because they have fewer employees across which to spread risk, making a single large claim proportionally more damaging.
Company Size Requirements
There’s no universal minimum, but ASO arrangements typically require at least a few dozen employees to be practical. Geisinger, for example, makes its ASO plans available to companies with 25 or more enrolled subscribers. Many carriers set higher thresholds, often in the range of 50 to 100 employees, because the financial math of self-funding depends on having a large enough group to make claims somewhat predictable from year to year. Very small groups face too much volatility for self-funding to make sense without extremely expensive stop-loss coverage that would erase the cost advantage.
ASO vs. Fully Insured: Key Differences
- Who pays claims: In an ASO, the employer pays claims from its own funds. In a fully insured plan, the insurance company pays.
- Cost structure: ASO employers pay variable costs based on actual claims plus a flat administrative fee. Fully insured employers pay a fixed monthly premium regardless of how many claims occur.
- Financial risk: The employer bears the risk in an ASO (usually with stop-loss protection). The insurer bears it in a fully insured plan.
- Plan flexibility: ASO gives employers more control over benefit design and access to claims data. Fully insured plans offer less customization but more predictability.
- Regulation: Self-funded ASO plans fall under federal ERISA rules. Fully insured plans are subject to state insurance regulations.
What This Means If You’re Covered by One
If your employer uses an ASO arrangement, your daily experience with healthcare coverage is largely unchanged. You’ll still have a network of providers, copays, deductibles, and a claims process that works like any other plan. Your insurance card may even carry the logo of a major insurer acting as the third-party administrator.
Where it can matter is in appeals and complaints. Because self-funded plans fall under federal rather than state jurisdiction, your state’s insurance commissioner generally can’t intervene in disputes about denied claims. Instead, the plan’s own internal appeals process and federal protections under ERISA apply. If you ever need to challenge a coverage decision, it helps to know whether your plan is self-funded through an ASO or fully insured, since the rules governing your options differ. Your plan documents or HR department can tell you which type you have.