- Manchester Area Convention and Visitors Bureau
- Manchester Community College
- Manchester Community College
- Manchester VA Medical Center
- Mandarin Gems
- Manhattan Bagels - All stores
- Manhattan Borough President's Office
- Manhattan Chamber of Commerce
- Manhattan Convention and Visitors Bureau
- Manhatten Bagels
- Manning Regional Healthcare Center
- Manor Park Inc.
- ManPower
- Manuel Lujan Insurance, Inc.
- Manufactured Housing Institute
- Manufacturers Association of Northwest PA
- Manufacturers Bank and Trust Co.
- Manville Borough
- Maple Grove Hospital
- Marathon County Board
- Marble Institute of America
- Marble Rock Fire/Rescue
- Marcos de Niza HOSA
- Marcum and Wallace Memorial Hospital
- Margaret J. Weston Medical Center
- Margaretville Memorial Hospital
- Maria Parham Medical Center
- Marian Manor
- Marian Regional Medical Center
- Marian University
- Maricopa County
- Maricopa County Department of Public Health
- Maricopa Integrated Health System
- Maricopa Medical Center
- Marietta College
- Marietta Memorial Hospital
- Marimon Business Systems, Inc.
- Marina Del Ray Hospital
- Marina Suites - Dewey Beach
- Marine Corps Material Comm.LHP
- Marine Credit Union
- Marine Spill Response Corporation
- Mariners Hospital
- Marines Caldwell County
- Marion County Medical Center
- Marion Drury Inn
- Marion General Hospital
- Marion General Hospital
- Marion School District
- Mark III Systems Inc.