Medicare Administrative Contractor (MAC): Definition + Cost-Report Role

By costreporting.aiPublished May 26, 2026

A Medicare Administrative Contractor (MAC) is a private insurance company that contracts with the Centers for Medicare & Medicaid Services (CMS) to administer the Medicare program for providers in a defined geographic jurisdiction. MACs process Medicare claims, audit annual cost reports, issue payment determinations (the Notice of Program Reimbursement, or NPR), and handle first-level provider appeals. The MAC structure replaced the older Fiscal Intermediary + Carrier system in 2008.

What the MAC does for the cost-report workflow

For Medicare-certified providers (HHA, Hospice, SNF, hospital, RHC, ESRD facility, CMHC, FQHC), the MAC is the entity on the other end of the cost-report submission. The provider files the annual cost report through the CMS MCReF portal within five months of the fiscal-year-end (42 CFR § 413.24(f)(2)). The MAC receives the submission, performs an acceptability check within ~30 days, conducts a desk review of the as-filed report, and schedules a field audit for higher-risk filings. The MAC then issues the Notice of Program Reimbursement (NPR), which is the final payment determination including any adjustments to the as-filed report. The provider has 180 days from the NPR to appeal to the Provider Reimbursement Review Board (PRRB) if the MAC's determination is disputed.

MAC jurisdictions

CMS divides the country into 12 Part A/B MAC jurisdictions plus 4 DME MAC jurisdictions. Your jurisdiction depends on the state where your provider is enrolled. Common Part A/B MACs as of the 2026 contracting cycle include Novitas Solutions, NGS (National Government Services), CGS Administrators, Palmetto GBA, WPS Government Health Administrators, Noridian Healthcare Solutions, and First Coast Service Options. Jurisdictions are reassigned during contracting cycles, so the authoritative source for your current MAC is the CMS jurisdiction map cited in the sources below. Different MACs publish their own submission-window calendars, jurisdiction-specific instructions, and audit protocols on top of the universal CMS Provider Reimbursement Manual — track your MAC's issuances alongside the CMS baseline.

MAC vs. RAC vs. UPIC vs. other CMS contractors

The MAC is the day-to-day claims-and-cost-report administrator. Other CMS-contracted entities operate in parallel with distinct scopes: the Recovery Audit Contractor (RAC) is focused on identifying improper Medicare payments (often after-the-fact, targeting overpayments); the Unified Program Integrity Contractor (UPIC) handles fraud, waste, and abuse investigations; the Quality Improvement Organization (QIO) handles quality-of-care reviews. These entities may all interact with the same provider's records, but their authority and procedural posture are distinct. The MAC issues the NPR; the RAC issues an overpayment demand; the UPIC issues investigation findings that may trigger administrative sanctions or criminal referral.

Related cost-report concepts

MAC rejections, amendments, NPRs, and audits — the post-submission MAC interaction surface in depth.
Cost-report deadlines and extensions — the five-month rule (42 CFR § 413.24(f)(2)) and the MAC-granted good-cause extension framework.
ECR file format and MCReF submission — the file the MAC actually receives and the portal used to submit it.

Common questions

What is a Medicare Administrative Contractor (MAC)?

A Medicare Administrative Contractor is a private insurance company under contract with the Centers for Medicare & Medicaid Services (CMS) to administer the Medicare program for providers in a defined geographic jurisdiction. MACs process Medicare claims, audit cost reports, issue payment determinations, conduct desk reviews and field audits, and serve as the first-level adjudicator for provider appeals. The MAC structure replaced the older Fiscal Intermediary (Part A) and Carrier (Part B) system in 2008 following Medicare contracting reform.

What does a MAC do for a Medicare cost report?

The MAC receives the provider's annual cost report (filed via the CMS MCReF portal), performs an acceptability check within 30 days of submission, conducts a desk review of the as-filed report, and may schedule a field audit for higher-risk filings. The MAC issues the Notice of Program Reimbursement (NPR), which is the final payment determination including any adjustments to the as-filed report. If the provider disputes the NPR, the first appeal step is a request for hearing to the MAC itself; the next level is the Provider Reimbursement Review Board (PRRB).

How many MACs are there and which one is mine?

There are currently 12 Part A/B MACs covering the 50 states plus DC and US territories, plus 4 DME MACs for durable medical equipment. The jurisdiction your provider falls under depends on the state where the provider is enrolled. CMS publishes the current jurisdiction map at the link cited below. As of the 2026 contracting cycle, the major Part A/B MACs include Novitas, NGS (National Government Services), CGS, Palmetto GBA, WPS, Noridian, and First Coast Service Options. Jurisdictions can be reassigned during contracting cycles, so always check the current CMS map when you need to confirm.

Is the MAC the same as the Recovery Audit Contractor (RAC) or the Unified Program Integrity Contractor (UPIC)?

No. The MAC is the day-to-day claims-and-cost-report administrator for a jurisdiction. The Recovery Audit Contractor (RAC) is a separate CMS-contracted entity focused on identifying improper Medicare payments (often after-the-fact, targeting overpayments). The Unified Program Integrity Contractor (UPIC) handles fraud, waste, and abuse investigations. All three may interact with the same provider's records, but their authority and scope are distinct. The MAC issues the NPR; the RAC issues an overpayment demand; the UPIC issues investigation findings that may trigger criminal referral.

What is the MAC's role after the Notice of Program Reimbursement is issued?

After the NPR is issued, the MAC continues to serve as the first-level adjudicator if the provider requests a hearing on the NPR. If the dispute is not resolved at the MAC level, the provider can escalate to the Provider Reimbursement Review Board (PRRB) within 180 days of the NPR. The MAC also handles cost-report reopenings under 42 CFR § 405.1885 — the MAC can reopen its own determination for up to 3 years from the NPR for any reason, and beyond 3 years for fraud or similar fault. Cross-link: see /guides/cost-report-rejections-amendments-audits for the full reopening framework.

How does the MAC affect cost-report preparation timing?

The MAC sets the operational expectations around the 5-month cost-report deadline (42 CFR § 413.24(f)(2)). The MAC is the entity that grants or denies a deadline extension request (limited to good-cause beyond the provider's control). The MAC also runs the acceptability check that determines whether your filing is treated as 'received' on the submission date or 'rejected pending cure' — a rejected report has 30 days to cure or the filing is treated as late. Providers preparing reports should track their MAC's published submission-window calendar and any jurisdiction-specific instructions the MAC issues in addition to the CMS Provider Reimbursement Manual.