A fully insured plan means that you are passing all of the risk onto your insurance carrier who charges you a flat monthly fee based on how they gauge the risk of insuring your employees.
If covered employees experience health issues and use the plan more, you will probably face a hefty increase in the monthly premium your business pays when your plan renews. Conversely, if your employees rarely use the insurance, you’re stuck playing a flat monthly rate no matter what. This model decreases the risk of month-to-month fluctuations but doesn’t provide any meaningful incentive for having healthy employees.