What is a Medicare Advantage Contractor (MAC)?

Summary:  Medicare Administrative Contractors (MACs) are private healthcare companies that have been contracted by the federal government to manage the day-to-day processing of Medicare claims. If you're a clinic, provider, or billing vendor submitting Medicare claims, you're interacting with a MAC—whether you realize it or not. These regional contractors handle millions of claims every year, determine whether they are valid and billable, and ensure compliance with federal and local policies. MACs are the gatekeepers between providers and payment.

MACs: The Middlemen of Medicare Billing

When and Why MACs were created

Medicare Administrative Contractors (MACs) were formally introduced through the Medicare Prescription Drug, Improvement, and Modernization Act (MMA) of 2003, which directed the Centers for Medicare & Medicaid Services (CMS) to consolidate and modernize the claims administration process.

Prior to MACs, Medicare used a patchwork system of fiscal intermediaries and carriers that often led to inefficiencies, regional inconsistencies, and outdated technology. The shift to MACs was designed to streamline operations, promote consistency across regions, enhance provider education, and improve the accuracy of claims adjudication. By competitively bidding private contractors to oversee specific jurisdictions, CMS aimed to reduce fraud, waste, and abuse while ensuring that claims were processed quickly and in compliance with federal regulations.

What do MACs look over and review?

MACs process both Part A (hospital/facility) and Part B (professional services) claims depending on the provider type. There are 12 jurisdictions in total, each with a separate MAC. These organizations are responsible for:

• Reviewing claims before payment
• Implementing National and Local Coverage Determinations (NCDs & LCDs)
• Managing provider enrollment and credentialing
• Offering education and audit findings to providers

For example, Noridian is the MAC for Jurisdiction E (California, Nevada, Hawaii), while NGS (National Government Services) covers Jurisdiction 6 (Illinois, Wisconsin, Minnesota). Different rules, forms, and policies may apply depending on your MAC. Source CMS Link

Why MACs Matter to Providers, Coders, and MSOs

Your MAC determines what documentation is required, what codes may be scrutinized, and how closely audits are enforced. Understanding your MAC’s preferences can be the difference between clean claims and constant denials.

How PCG Support MAC-Specific Compliance

PCG Software helps clinics and health plans stay compliant across all MAC jurisdictions. Our Virtual Examiner® platform flags potential claim errors based on jurisdictional policies, including:

• Overused CPT codes flagged by your MAC
• Missing documentation that could trigger a denial
• Modifier misuse or unbundling practices

Our tools allow coders, billers, and compliance teams to align internal processes with MAC-specific expectations. We also track and update jurisdictional LCD changes quarterly to reduce the burden on your staff.

If your organization serves multiple regions or frequently changes Medicare networks, Virtual Examiner ensures uniform compliance across jurisdictions.