| M.C. Dixon Lumber Company, Inc. AL | Manufacturing | 0 | — | C |
| M.C. Gutherie Lumber Company MI | Wholesale Trade | 0 | — | C |
| M.C. Paulino, Inc. GU | Construction | 1 | $52,000 | — |
| M.C. Tank Transport, Inc. OH | Transportation & Warehousing | 0 | — | B |
| M.C. Velar FL | Construction | 0 | — | A |
| M.C. Velar Construction Corp. FL | Construction | 0 | — | A |
| M.C.I CA | Manufacturing | 0 | — | D |
| M.C.I Foods, Inc. CA | Manufacturing | 0 | — | A |
| M.C.I. INC. dba MCI CARPET ONE FLOOR AND HOME MN | Retail Trade | 0 | — | A |
| M.C.O. CONSTRUCTION AND SERVICES, INC. FL | Construction | 0 | — | A |
| M.D Miller Co. t/a The Marksmen Company MD | Construction | 0 | — | A |
| M.D. Construction & Consulting Inc. CA | Construction | 0 | — | A |
| M.D. Descant, LLC LA | Construction | 0 | — | F |
| M.D. Service Plumbing, Inc CO | Construction | 0 | — | F |
| M.D. Stainless Services CA | Construction | 0 | — | A |
| M.E. COLLINS CONTRACTING CO., INC. NE | Construction | 0 | — | F |
| M.E. Flow VA | Construction | 0 | — | F |
| M.E. Fox & Company, Inc. CA | — | 0 | — | — |
| M.E. Industries TN | Manufacturing | 0 | — | A |
| M.E.S.O., Inc. OH | Other Services | 0 | — | D |
| M.G. Design Associates Corporation FL | — | 0 | — | — |
| M.G. Design Associates Corporation WI | — | 0 | — | — |
| M.G. Dyess MS | Construction | 0 | — | A |
| M.G. Oil Company, Inc. SD | Retail Trade | 0 | — | A |
| M.G. Oil Company, Inc. WY | Wholesale Trade | 0 | — | F |
| M.G. Waldbaum Company MN | Manufacturing | 1 | $97,604 | — |
| M.G.R. FARM LABOR CONTRACTOR CA | Agriculture & Forestry | 0 | — | F |
| M.H. Eby, Inc. IA | Manufacturing | 0 | — | F |
| M.H. Eby, Inc. OH | Manufacturing | 0 | — | F |
| M.H. Eby, Inc. PA | Manufacturing | 0 | — | F |
| M.H. Williams Construction Group, Inc. FL | Construction | 0 | — | A |
| M.I. Industries, Inc. MO | Manufacturing | 1 | $125,986 | — |
| M.J. Baxter Drilling Company CA | Construction | 0 | — | A |
| M.J. Cataldo, Inc. MA | Construction | 0 | — | F |
| M.J. Design Associates, INC OH | Administrative & Waste Services | 0 | — | A |
| M.J. Harris Construction Services, LLC AL | Construction | 0 | — | A |
| M.J. Moran Inc. MA | Construction | 0 | — | A |
| M.J. Nester Equipment Sales, LLC PA | Construction | 0 | — | A |
| M.J. Sheridan of Texas Inc. TX | Construction | 0 | — | A |
| M.J. Soffe LLC NC | — | 0 | — | — |
| M.K. Chambers Company MI | Manufacturing | 0 | — | F |
| M.K.S. Plumbing Corporation NY | Construction | 0 | — | F |
| M.L. Albright & Sons, Inc. ID | Construction | 0 | — | F |
| M.L. Chartier Inc. MI | Administrative & Waste Services | 0 | — | C |
| M.L. McDonald Sales Company, LLC MA | Construction | 0 | — | D |
| M.L. Ruberton Construction Co., Inc. NJ | Construction | 0 | — | F |
| M.L.Jones LLC OK | Construction | 0 | — | A |
| M.M.D d/b/a The Allstaff Group IL | Administrative & Waste Services | 0 | — | A |
| M.P. Fish Market Inc CA | Retail Trade | 0 | — | A |
| M.R. Pittman Group, LLC LA | Construction | 0 | — | B |
