Any of a wide array of arrangements in which two or more small employers purchase health insurance collectively, often through a common intermediary who acts on their collective behalf. Such arrangements may go by many different names, including cooperatives, alliances, or business groups on health. They differ from one another along a number of dimensions, including governance, functions, and status under federal and state laws. While some are entirely private enterprises, others are set up or chartered by states. Some centralize more of the purchasing functions, such as risk pooling, price negotiation, choice of health plans offered to employees, and various administrative tasks. Depending on their functions, these groups may be subject to different state and/or federal rules. For example, they may be regulated as Multiple Employer Welfare Arrangements (“MEWAs”).