OBRA, TEFRA and DEFRA are laws that enable active employees and their spouses, enrolled in a group health plan, to make their HealthNow coverage primary to Medicare. OBRA Affects employers with 100 or more full-time and/or part-time active employees. TEFRA/DEFRA Affect employers with 20 or more full-time and/or part-time employees and that offer health insurance through the group. Omnibus Budget Reconciliation Act - Federal (OBRA) OBRA Specifications. This law affects employers with 100 or more employees. When an active employee/dependent is covered by his/her employer enrolled in the active group and has Medicare due to a disability other than End Stage Renal Disease, the group coverage is primary to Medicare.