| MEMaynard Equipment INC | Brownsboro | AL | — | ◇ UNVERIFIED |
| MSMay Specialty Fabricators, INC. | Register | GA | — | ◇ UNVERIFIED |
 Mayville Engineering Company INC Dba Mec | Vanderbilt | MI | — | ◇ UNVERIFIED |
| MWMazzella Welding & Fabrication INC | Wellsburg | WV | — | ◇ UNVERIFIED |
 M-b Companies INC | Chilton | WI | — | ◇ UNVERIFIED |
| MEMbm Enterprises, INC. | Pleasant Plains | AR | — | ◇ UNVERIFIED |
| MSM&b Steel Fabricators, INC. | Orlando | FL | — | ◇ UNVERIFIED |
| MAMcabee Assembly Facility | Tuscaloosa | AL | — | ◇ UNVERIFIED |
| MMMcadams & Mcadams, INC. D/b/a M & M Welding | Archdale | NC | — | ◇ UNVERIFIED |
| MWMcbrides Welding Dba American Iron | Ridgecrest | CA | — | ◇ UNVERIFIED |
| MSMcb Steel, INC. | Bessemer | AL | — | ◇ UNVERIFIED |
| MIMcclister INC | Tualatin | OR | — | ◇ UNVERIFIED |
| MIMcdermott INC | Gibson | LA | — | ◇ UNVERIFIED |
| MIMcdermott INC - Morgan City Fabrication Facility - Amelia Yard | Amelia | LA | — | ◇ UNVERIFIED |
| MMMcdonough Marine Service | Metairie | LA | — | ◇ UNVERIFIED |
| MMMcelroy Metal Mill INC | Monroe | LA | — | ◇ UNVERIFIED |
| MMMcelroy Metal Mill INC Dba Mcelroy Metal | Adelanto | CA | — | ◇ UNVERIFIED |
| MTMce Technologies INC | Seattle | WA | — | ◇ UNVERIFIED |
| MLMcewen Lighting Studio | Berkeley | CA | — | ◇ UNVERIFIED |
| MMMcfarlane Mfg CO | Sauk City | WI | — | ◇ UNVERIFIED |
| MIMcgregor Ind Inc/dunmore Plt | Dunmore | PA | — | ◇ UNVERIFIED |
 Mclaughlin Body CO | East Moline | IL | — | ◇ UNVERIFIED |
| MSMcmahno Steel CO | Chula Vista | CA | — | ◇ UNVERIFIED |
| MFMcm Fabricators, INC. Dba Global Fabricators | Shafter | CA | — | ◇ UNVERIFIED |
| MSMcneely Steel & Supply | Leavenworth | KS | — | ◇ UNVERIFIED |
| MCMcnichols Company | Garland | TX | — | ◇ UNVERIFIED |
| MIMcReynolds Investments LLC | Waterford | WI | — | ◇ UNVERIFIED |
| MMMcswain Metal Fabrication, INC. | Englewood | CO | — | ◇ UNVERIFIED |
| MSMcwhirter Steel | Lancaster | CA | — | ◇ UNVERIFIED |
| MCMDI Corporation | Cheney | KS | — | ◇ UNVERIFIED |
| MCMDI Corporation | Cheney | KS | — | ◇ UNVERIFIED |
 Meadow-burke Products | Hazleton | PA | — | ◇ UNVERIFIED |
| MEMeagher Equipment Repair | Oroville | CA | — | ◇ UNVERIFIED |
| MGMec General Construction INC. | Brooklyn | NY | — | ◇ UNVERIFIED |
| MGMec General Construction INC. | Brooklyn | NY | — | ◇ UNVERIFIED |
| MAMechanical and Industrial Steel Services, INC. | Channahon | IL | — | ◇ UNVERIFIED |
| MHMedway Hall Development Group, Inc. | Jacksonville | FL | — | ◇ UNVERIFIED |
| MPMehlberg Property, LLC | Wasco | CA | — | ◇ UNVERIFIED |
| MMMeiers Modern Metals, LLC | Portland | OR | — | ◇ UNVERIFIED |
| MPMellies Products INC. | Morganville | KS | — | ◇ UNVERIFIED |
| MMMelrose Metal Products, INC | Fremont | CA | — | ◇ UNVERIFIED |
| MPMelting Point Welding & Fabrication, Inc. | Killingly | CT | — | ◇ UNVERIFIED |
| MBMelvin Baltodano | Ontario | CA | — | ◇ UNVERIFIED |
| MWMelvin Wrought Iron & Ornamental | Ontario | CA | — | ◇ UNVERIFIED |
| MSMemphis Sheet Metal Works INC | Memphis | TN | — | ◇ UNVERIFIED |
| MMMenard Manufacturing INC. | Dewitt | AR | — | ◇ UNVERIFIED |
| MMMenator Metal Works LLC | Winneconne | WI | — | ◇ UNVERIFIED |
| MSMendel Steel & Ornamental Iron Company | Bethel Park | PA | — | ◇ UNVERIFIED |
| MOMendoza's Ornamental Iron | Fullerton | CA | — | ◇ UNVERIFIED |
| MMMerchants Metals, LLC | Jacksonville | FL | — | ◇ UNVERIFIED |
