- MacGray
- Macias, Gini and Company LLP
- MacMurray College
- MacNeal Hospital
- Macomb County
- Macomb County Board of Commissioners
- Macomb County, Board of Commissioners - Roseville
- Macomb County, Board of Commissioners - Mt. Clemens
- Macon County
- Macon Program for Progress
- Macon Transit Authority
- Macro Enterprises Inc.
- Macstir Inc. dba Mac Travel
- Macys, Natrona
- Mad Dogs Enterprises
- Madera Community Hospital
- Madera County
- Madison Avenue Inc.
- Madison County
- Madison County Convention and Visitors Bureau
- Madison County Engineer's Office
- Madison County Health Care System
- Madison County Health Department
- Madison County Health Dept.
- Madison County Memorial Hospital
- Madison Hospital
- Madison Regional Health System
- MAG-LEV Transit International, Inc.
- Magee General Hospital
- Magee Research Institute and Foundation
- Magee-Womens Hospital of UPMC
- Magellan Health Services
- Magellan Health Services
- Magic Valley Concrete Ltd.
- Magnolia Hall Nursing Center
- Magnolia Regional Health Center
- Magnolia Regional Medical Center
- Magnotti and Son, Inc.-The Fireplace and Patio Place
- Magruder Hospital
- Mahan Rykiel Associates
- Mahaska Health Partnership
- MAHEC Dep. OB-GYN
- Mahle Tennex North America, Inc
- Mahoning County Department of Job and Family Services and Child Support Enforcement Agency
- Maimonides Medical Center
- Maimonides Midwood Community Hospital
- Main Line Health Corporate Office-Radnor
- Main Line Health Home Care
- MAIN Medical Inc.
- Main Street Mortgage and Investment Corporation