This document is about an annual report on private sector employer-sponsored group health plans that filed Form 5500 in 2017. It provides detailed statistics on the characteristics, funding arrangements, participants, assets, liabilities, contributions, and expenses of these group health plans. The report classifies plans as self-insured, fully insured, or mixed-insured based on their funding structure and the presence of insurance contracts and trust funds. Key findings include that 41% of the nearly 58,000 plans were self-insured, 53% were fully insured, and 7% were mixed-insured, with the mixed-insured plans covering 35% of participants and holding 57% of total assets.