What Is the Role of a Medicare Administrative Contractor?

Medicare administrative contractors (MACs) are private health insurance companies that work across states to process claims under Original Medicare. They play an important administrative role in the Medicare system.

Since its founding in 1966, Medicare has tasked private health insurance companies with processing beneficiaries’ claims. Today, these companies are called Medicare administrative contractors, or MACs.

MACs serve as operational intermediaries between the healthcare providers enrolled in Medicare and the program itself. The companies serving as MACs operate in set geographic regions, called jurisdictions.

MACs only process claims for beneficiaries of Part A and Part B. Medicare Advantage (Part C) claims undergo separate processing.

In this article, we discuss more about the function of MACs and their types.

In 2024, there were more than 33 million Americans enrolled in Original Medicare.

Due to the size of this beneficiary population and its geographic diversity, the Centers for Medicare & Medicaid Services (CMS) employs MACs to help streamline its administration.

According to the CMS, MACs served 1.2 million healthcare providers in 2023.

MACs only work with providers enrolled in the Medicare fee-for-service (FFS) program. This includes Original Medicare (parts A and B).

Independent private insurers offer and administer Medicare Advantage plans, so they do not require the services of MACs.

These MACs are responsible for processing Part A and Part B claims. They work on behalf of physicians, institutions, and suppliers.

These MACs process claims for durable medical equipment (DME), prosthetics, and orthotics.

There are four DME MAC jurisdictions within the United States, labeled A, B, C, and D.

Of the 12 A/B MAC jurisdictions, four are responsible for processing home health and hospice (HH+H) claims.

The A/B MAC jurisdictions that process HH+H claims are 6, 15, K, and M. However, the geographic boundaries of the HH+H areas differ from those of the coinciding A/B MAC jurisdictions.

MACs work within set geographic jurisdictions. A person can find their MAC by locating their state in one of the tables in the previous section.

Alternatively, they can look for their state on the CMS website.

MACs work within set geographic jurisdictions. A person can find their MAC by locating their state in one of the tables in the previous section.

Alternatively, they can look for their state on the CMS website.

There are 12 A/B MAC jurisdictions in the United States, but there are 7 separate companies with contracts.

There are two separate companies with contracts across the four DME MAC jurisdictions.

There are 12 A/B MAC jurisdictions in the United States, but there are 7 separate companies with contracts.

There are two separate companies with contracts across the four DME MAC jurisdictions.

Medicare administrative contractors (MACs) are private companies with contracts to administer the Medicare fee-for-service program in regional jurisdictions.

They assist with processing beneficiary claims, enrolling healthcare professionals in the Medicare program, and performing various other operational tasks.