| MA | MD | ME | MI | MO | MR | MU | MY |
| Index entry | NAICS Code | U.S. NAICS Title |
|---|---|---|
| MRF (materials recovery facilities) | 562920 | Materials Recovery Facilities |
| MRI (magnetic resonance imaging) centers | 621512 | Diagnostic Imaging Centers |
| MRI (magnetic resonance imaging) medical diagnostic equipment manufacturing | 334510 | Navigational, Measuring, Electromedical, and Control Instruments Manufacturing |
| MA | MD | ME | MI | MO | MR | MU | MY |