Minimum participation requirements vary depending on whether the group insurance plan is a noncontributory plan or a contributory plan. Typically, a noncontributory plan requires 100 percent participation of all eligible employees; to do otherwise would be discriminatory. Because participation in a contributory plan is voluntary, however, some employees may decide not to enroll in the plan. Most insurers require that at least 75 percent of the eligible employees in a contributory group insurance plan participate in the plan.5 A higher percentage of employees may participate in the plan, but a participation level lower than 75 percent would cause the group to lose its eligibility for coverage.