A self-funded (or self-insured) plan is an employer health plan in which the employer pays its employees' medical and prescription claims directly from its own money, usually hiring an insurance company or PBM only to administer the plan. A fully-insured plan is the opposite arrangement: the employer pays premiums to an insurer, and the insurer takes on the cost of claims. Most large employers self-fund: in KFF's 2025 employer survey, 80% of covered workers at firms with 200 or more workers were in self-funded plans (KFF (external link)). That's why two people with the "same" insurance card can have very different GLP-1 coverage. The employer decides whether weight-management drugs are included, and the carrier just runs the plan.
The distinction matters for a second reason. Self-funded plans are governed by the federal ERISA law, which generally exempts them from state insurance mandates, so a state law requiring obesity-treatment coverage typically does not reach a self-funded plan. If your GLP-1 is excluded, the most effective route is often asking the employer to change the plan; see how employer self-funded plans decide GLP-1 coverage and how coverage mandates differ by state.