| M. B. Kahn Construction Co. Inc. NC | Construction | 0 | — | A |
| M. B. Kahn Construction Co. Inc. VA | Construction | 0 | — | A |
| M. B. Kahn Construction Co. Inc., VA | Construction | 0 | — | A |
| M. B. Kahn Construction Co., Inc. SC | Construction | 0 | — | A |
| M. B. Kahnconstruction Co. Inc. VA | Construction | 0 | — | A |
| M. Block & Sons, Inc. IL | — | 0 | — | — |
| M. Block and Sons TN | — | 0 | — | — |
| M. C. Miller Co., Inc. FL | Manufacturing | 0 | — | A |
| M. Calosso & Son, Inc CA | Wholesale Trade | 0 | — | F |
| M. Cohen and Sons, Inc PA | Manufacturing | 0 | — | F |
| M. E. Construction, Inc. FL | Construction | 0 | — | F |
| M. G. McGrath, Inc. MN | Construction | 0 | — | B |
| M. Gaw, Inc. CA | Construction | 0 | — | F |
| M. Glosser & Sons, Inc. PA | Wholesale Trade | 0 | — | F |
| M. Greenberg Construction, Inc. AZ | Construction | 0 | — | D |
| M. Holland & Sons Construction, Inc. MA | Construction | 0 | — | D |
| M. J. Electric LLC MI | Construction | 0 | — | B |
| M. J. Kellner Co., Inc IL | Wholesale Trade | 0 | — | D |
| M. L. Caccamise Electric Corp. NY | Construction | 0 | — | F |
| M. L. Schmitt, Inc. MA | Construction | 0 | — | D |
| M. Lipsitz & Co., Ltd. TX | Wholesale Trade | 0 | — | F |
| M. Ludvik Engineering PC NY | Professional & Technical Services | 1 | $89,000 | — |
| M. Nelson Barnes & Sons, Inc. MD | Construction | 0 | — | A |
| M. O'Herron Company PA | Construction | 0 | — | A |
| M. Potteiger Inc. PA | Construction | 0 | — | A |
| M. Price Distributing Company VA | Transportation & Warehousing | 0 | — | F |
| M. R. Tudor - California, Inc. CA | Real Estate | 2 | $87,500 | — |
| M. Raess & Son Trucking LLC IL | Transportation & Warehousing | 0 | — | C |
| M. Rivera Construction Co. OH | Construction | 0 | — | A |
| M. Schneider Soap & Chemical Co., Inc. NY | Manufacturing | 0 | — | A |
| M. Shiroma Painting Co., Inc. HI | Construction | 4 | $52,380 | — |
| M. Slavin & Sons, Ltd. NY | — | 0 | — | — |
| M. Spiegel & Sons Oil Corp NY | Wholesale Trade | 0 | — | A |
| M. Sullivan Construction NY | Construction | 0 | — | A |
| M. W. Reid Welding, Inc. CA | Manufacturing | 0 | — | F |
| M. W. Tighe Roofing, Inc. WI | Construction | 0 | — | F |
| M.A. Concrete Construction, Inc. CO | Construction | 0 | — | F |
| M.A. Ford Manufacturing Company Inc IA | Manufacturing | 0 | — | F |
| M.A. Ford Mfg Co Inc FL | Manufacturing | 0 | — | D |
| M.A. Patout & Son Limited, LLC LA | Manufacturing | 0 | — | A |
| M.A. PATOUT SUGAR MILL LA | Agriculture & Forestry | 0 | — | A |
| M.A. Silva Corks USA CA | Manufacturing | 0 | — | A |
| M.A.A.C. Property Services MI | Administrative & Waste Services | 0 | — | F |
| M.A.S. INDUSTRIES INC WI | Manufacturing | 0 | — | A |
| M.AI UNBOUND, INC. CA | Professional & Technical Services | 1 | $190,000 | — |
| M.B. Kahn Construction Co. Inc. SC | Construction | 0 | — | A |
| M.B. Manufacturing Corp. OH | Manufacturing | 0 | — | F |
| M.B. Sturgis, Inc. MO | Manufacturing | 0 | — | F |
| M.B.O Precast, Inc. MA | Manufacturing | 0 | — | F |
| M.C. Dean, Inc. VA | Professional & Technical Services | 20 | $122,927 | C |
