Look at your insurance card. There is a familiar logo on it, probably Aetna or Cigna or a Blue Cross plan, and a customer service number, and it all implies that this company collected a premium from your employer and is now on the hook for your medical bills. For about two thirds of people with job-based coverage, that is not what is happening. In a self-funded health plan, your employer pays your claims out of its own money and rents the insurance company’s name, network, and claims software. KFF’s 2025 Employer Health Benefits Survey puts it at 67% of covered workers, including 80% at firms with 200 or more employees and 27% at firms with 10 to 199. Almost none of them have been told.
This matters right now because open enrollment is landing on an unusually expensive year. Mercer’s survey of 1,800 employers, released in September 2026, projects health benefit costs per employee rising 8.2% in 2027, the steepest jump since 2003, with two thirds of employers of 500 or more planning to push some of that into paycheck deductions. Understanding where your plan’s money actually comes from tells you a lot about which of those changes are negotiable and which rules apply when something goes wrong.
The insurance company on your card is a vendor
In a fully insured plan, the mechanics are what everyone assumes. The employer pays a premium to an insurance company, the insurance company promises to pay claims, and if the workforce has a terrible year the insurer eats the loss. Risk has genuinely been transferred.
In a self-funded plan, no premium exists. The employer sets aside money, pays each claim as it arrives, and hires an insurance company as a third party administrator to process claims, run the provider network, and answer the phone number on your card. That administrator is paid a fee per employee per month. It is not paying your surgeon. Your employer is. The reason so many employers made this switch is the flip side of the same coin: in a good claims year, the leftover money stays with the employer instead of becoming an insurer’s profit.
Smaller employers have joined through a middle option called level funding, which bundles a modest self-funded component with insurance that caps the downside. KFF found 37% of covered workers at small firms in level-funded plans in 2025. So the old rule of thumb, that self-funding is for big companies, is about a decade out of date.
What your paycheck deduction really buys
Run the numbers from the 2025 KFF survey. Average family coverage cost $26,993 for the year, of which the worker paid $6,850 and the employer covered the remaining $20,143. That is $2,249 a month in total cost, with $571 of it coming out of your paychecks, or a little over 25% of the whole thing.
In a fully insured plan, that entire $2,249 leaves the building every month whether anyone gets sick or not. In a self-funded plan, it does not. Your employer books something close to that amount as a budget, spends what claims require, and keeps what is left. Now apply Mercer’s 8.2% projection for 2027. Total family cost goes from $26,993 to roughly $29,206, an increase of about $2,213. If your share holds steady at a quarter, your own contribution climbs from $6,850 to about $7,412, roughly $47 more per month. The part worth noticing is that in a self-funded plan there is no outside insurer setting that number. Your employer is choosing how much of its own cost increase to move onto you, which is a budget decision rather than a market price.
Stop-loss is the real insurance, and it does not cover you
No employer wants unlimited exposure to a single catastrophic case, so self-funded plans buy stop-loss insurance. It reimburses the employer once claims pass a threshold, either for one person’s claims or for the plan’s total spending in a year.
Read that sentence again, because the direction matters. Stop-loss is a contract between the employer and an insurer. You are not a party to it, you cannot claim under it, and it does not guarantee that your benefits get paid. It exists so that one premature birth or one transplant does not wreck the company’s quarter. Your protection comes from the plan document your employer wrote, not from a stop-loss policy you will never see.
State insurance mandates stop at the ERISA line
Every state has a list of things insurance policies sold in that state must cover. Fertility treatment, hearing aids, and autism services are common examples, and they change year to year as legislatures expand them.
Self-funded plans skip nearly all of it. ERISA’s preemption clause, and specifically the deemer clause at 29 U.S.C. 1144(b)(2)(B), says an employee benefit plan cannot be treated as an insurance company for purposes of state laws regulating insurance. So a state can require insurers to cover IVF, and the fully insured plan down the street has to comply, while your self-funded plan at a company headquartered in the same city does not. Your coworker in another state has identical coverage to yours, which is the whole point from the employer’s side: one plan, one set of rules, fifty states. From your side it means that reading a headline about your state mandating a benefit tells you nothing until you know how your plan is funded.
A denied claim takes a different road
If a fully insured plan denies your claim and you exhaust the internal appeal, you generally go to your state’s external review process, run by the state insurance department, which also takes consumer complaints and can put real pressure on the insurer.
Self-funded ERISA plans use a federal process instead. Under the Affordable Care Act rules, the plan contracts with at least three accredited independent review organizations and rotates cases among them so it cannot steer every appeal to a favorite. The reviewer’s decision binds the plan. What you lose is the state regulator: calling your state insurance commissioner about a self-funded plan usually gets you told, correctly, that they have no jurisdiction. The federal Department of Labor oversees these plans, so the appeal itself is your main tool rather than a regulator who licenses the company. The same funding question explains a lot about continuation coverage after you leave, which we covered in how COBRA works, and about why your prescription costs what it does, which we took apart in how pharmacy benefit managers work.
Finding out which one you have
Three places will tell you. Your summary plan description has a funding section, and the phrase to look for is some version of benefits being paid from the general assets of the employer. Your ID card often says administered by or a similar formulation rather than naming an insurer as the underwriter. And because self-funded plans file a Form 5500 with the Department of Labor, you can look your employer up in the public EFAST2 filing database and read the attached schedules yourself.
Ask HR during open enrollment. It is a one-sentence question, the answer is not confidential, and it changes how you read everything else in the packet. A self-funded health plan is not worse than a fully insured one, and plenty of them are more generous than state minimums require. But it means the entity deciding what your care costs and what gets covered is the same entity that signs your paycheck, and you should at least know that before you pick a plan.