| MSMartha S Materials INC | Lexington | KY | — | ◇ UNVERIFIED |
| MIMarti, Inc. | Bemidji | MN | — | ◇ UNVERIFIED |
| MSMartinez Steel | San Francisco | CA | — | ◇ UNVERIFIED |
| MIMartin Iron Works, INC | Reno | NV | — | ◇ UNVERIFIED |
| MIMartin Iron Works, INC. | Reno | NV | — | ◇ UNVERIFIED |
| MMMartin Manufactuirng, INC. | Sapulpa | OK | — | ◇ UNVERIFIED |
| MHMartin-Pittman Holdings, Inc. | Indianapolis | IN | — | ◇ UNVERIFIED |
| MSMartin Steel Constructors | Eleele | HI | — | ◇ UNVERIFIED |
| MWMartin Welding and Fabrication LLC | Contoocook | NH | — | ◇ UNVERIFIED |
| MSMaryland Structural Fabricators INC | Millington | MD | — | ◇ UNVERIFIED |
| MLMascoat LLC | West Monroe | LA | — | ◇ UNVERIFIED |
| MHMascotte Home Security Products INC | Portland | OR | — | ◇ UNVERIFIED |
| MSMason Structural Steel INC. | Walton Hills | OH | — | ◇ UNVERIFIED |
| MWMason West, INC | Placentia | CA | — | ◇ UNVERIFIED |
| MWMaspeth Welding, INC | New York | NY | — | ◇ UNVERIFIED |
| MMMass Machine & Fabricating Company | Washington | PA | — | ◇ UNVERIFIED |
| MMMatcor Metal Fabrication | Morton | IL | — | ◇ UNVERIFIED |
| MCMaterial Control Systems, INC. | Cordova | IL | — | ◇ UNVERIFIED |
| MHMaterial Handling Technologies, INC. | North Syracuse | NY | — | ◇ UNVERIFIED |
| MRMaterial Resources INC | Forest Grove | OR | — | ◇ UNVERIFIED |
| MIMattei, INC. | Harlingen | TX | — | ◇ UNVERIFIED |
| MIMattessich Iron, LLC | Memphis | NY | — | ◇ UNVERIFIED |
| MIMattessich Iron, LLC | Baldwinsville | NY | — | ◇ UNVERIFIED |
| MBMatthew Bronze West Annex Facility | Kingwood | WV | — | ◇ UNVERIFIED |
| MBMaura Buildings, Incorporated | Lebanon | PA | — | ◇ UNVERIFIED |
| MMMaurice Mesple Dba Mesples Machine Shop and Pump | Fresno | CA | — | ◇ UNVERIFIED |
| MIMaxanns INC | Greeley | CO | — | ◇ UNVERIFIED |
| MSMay Specialty Fabricators, INC. | Register | GA | — | ◇ UNVERIFIED |
 Mayville Engineering Company INC Dba Mec | Vanderbilt | MI | — | ◇ UNVERIFIED |
| MEMbm Enterprises, INC. | Pleasant Plains | AR | — | ◇ UNVERIFIED |
| MSM&b Steel Fabricators, INC. | Orlando | FL | — | ◇ UNVERIFIED |
| MMMcadams & Mcadams, INC. D/b/a M & M Welding | Archdale | NC | — | ◇ UNVERIFIED |
| MWMcbrides Welding Dba American Iron | Ridgecrest | CA | — | ◇ UNVERIFIED |
| MIMcclister INC | Tualatin | OR | — | ◇ UNVERIFIED |
| MMMcdonough Marine Service | Metairie | LA | — | ◇ UNVERIFIED |
| MMMcelroy Metal Mill INC | Monroe | LA | — | ◇ UNVERIFIED |
| MMMcelroy Metal Mill INC Dba Mcelroy Metal | Adelanto | CA | — | ◇ UNVERIFIED |
| MLMcewen Lighting Studio | Berkeley | CA | — | ◇ UNVERIFIED |
| MMMcfarlane Mfg CO | Sauk City | WI | — | ◇ UNVERIFIED |
| MHMckee Holdings LLC | Sandy | OR | — | ◇ UNVERIFIED |
| MSMcmahno Steel CO | Chula Vista | CA | — | ◇ UNVERIFIED |
| MFMcm Fabricators, INC. Dba Global Fabricators | Shafter | CA | — | ◇ UNVERIFIED |
| MCMcnichols Company | Garland | TX | — | ◇ UNVERIFIED |
| MIMcReynolds Investments LLC | Waterford | WI | — | ◇ UNVERIFIED |
| MSMcwhirter Steel | Lancaster | CA | — | ◇ UNVERIFIED |
| MCMDI Corporation | Cheney | KS | — | ◇ UNVERIFIED |
| MCMDI Corporation | Cheney | KS | — | ◇ UNVERIFIED |
 Meadow-burke Products | Hazleton | PA | — | ◇ UNVERIFIED |
| MGMec General Construction INC. | Brooklyn | NY | — | ◇ UNVERIFIED |
| MGMec General Construction INC. | Brooklyn | NY | — | ◇ UNVERIFIED |
