| Multilevel Current Source Inverter | Academic & Science |
| Mathematics and Computers in Sciences and Industry | Academic & Science |
| Mix Channel State Information | Academic & Science |
| MCSi, Inc. (formerly Miami Computing Supply Corporation) | Business |
| Mining Consulting Services, Inc. | Business |
| Molli Computer Services, Inc. | Business |
| Managed Care Systems, Inc. | Business |
| Municipal Collection Services Inc | Business |
| Mission Critical Solutions Inc | Business |
| Millerstown Community Success Inc | Business |
| Mike Cindia Sales Inc | Business |
| Motorola Cellular Services Inc | Business |
| Mechanical Contracting Services Inc | Business |
| Moore Control Systems Inc | Business |
| Missionary Care Services International | Community |
| Michigan Community Services Incorporated | Community |
| Michigan Community Services Inc | Community |
| Midtown Community School Initiative | Community |
| Microsoft Computing Safety Index | Computing |
| MC Soluzioni Informatiche | Computing |
| Minnesota Computer Systems Inc | Computing |
| Media Consultants And System Integrators | General |
| Member Chartered Institute for Securities & Investment | General |
| Modified Caregiver Strain Index | General |
| Michigan Consumer Sentiment Index | General |
| Munroe Center for Social Inquiry | General |
| Mascaro Center for Sustainable Innovation | General |
| Multiple Capture Single Image | General |
| Modern and Contemporary Studies Initiative | General |
| Mays Construction Specialties Inc | General |
| Marine Conservation Science Institute | Governmental |
| Magical Crime Scene Investigation | Governmental |