- 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
- Maine Innkeepers Association
- Maine Medical Center
- Maine Medical Center - Stevens Avenue
- Maine Office of Substance Abuse and Mental Health Services
- Maine Parent Federation
- MaineGeneral Medical Center
- MaineGeneral Rehabilitation and Long Term Care at Glenridge
- Maita Toyota of Sacramento
- Major County
- Major Hospital
- Major League Baseball Players Alumni
- Malco Theatres
- Malnove Holding Company, Inc.
- Malone College
- Management Advisors, Inc.
- Management Information Systems
- Management Information Systems
- Management Options Inc.
- Management Reemiters of Columbus
- Management Science Associates, Inc.
- Management Solutions Plus, Inc.
- Management Support Technology Inc.
- Manatee Chamber of Commerce
- Manatee County Clerk of Circuit Court
- Manatee County Family YMCA, Inc.
- Manatee Memorial Hospital
- Manati Medical Center
- Manatron
- Manatron