MAC (Medicare Administrative Contractor)

Private contractor that processes Medicare Part A and Part B claims for an assigned jurisdiction. 12 active MAC jurisdictions covering all 50 states plus territories. MACs publish jurisdiction-specific Local Coverage Determinations and locality-based fee schedules. Examples: Noridian (J-E and J-F), Palmetto GBA (J-J and J-M), CGS (J-15), WPS (J-5 and J-8), Novitas (J-H and J-L). Knowing your MAC jurisdiction matters because LCDs, fee schedules, and audit patterns differ.