| MAMarine Accessories Corporation (mac) | Maryville | TN | — | ◇ UNVERIFIED |
| MSMarion Steel Fabrication Incorporated | Marion | IN | — | ◇ UNVERIFIED |
| MIMaritime International INC | Broussard | LA | — | ◇ UNVERIFIED |
| MCMarley Cooling Tower Company | Louisville | KY | — | ◇ UNVERIFIED |
| MSMarshall Steel Services INC. | Arvada | CO | — | ◇ UNVERIFIED |
| MSMartin Steel INC | Huntington | WV | — | ◇ UNVERIFIED |
| MWMazzella Welding & Fabrication INC | Wellsburg | WV | — | ◇ UNVERIFIED |
| MAMcabee Assembly Facility | Tuscaloosa | AL | — | ◇ UNVERIFIED |
| MSMcb Steel, INC. | Bessemer | AL | — | ◇ UNVERIFIED |
| MIMcdermott INC | Gibson | LA | — | ◇ UNVERIFIED |
| MIMcdermott INC - Morgan City Fabrication Facility - Amelia Yard | Amelia | LA | — | ◇ UNVERIFIED |
| MTMce Technologies INC | Seattle | WA | — | ◇ UNVERIFIED |
 Mclaughlin Body CO | East Moline | IL | — | ◇ UNVERIFIED |
| MSMcneely Steel & Supply | Leavenworth | KS | — | ◇ UNVERIFIED |
| MIMct Industries Inc, Government Manufacturing | Bernalillo | NM | — | ◇ UNVERIFIED |
| MOMetalcraft of Mayville | West Bend | WI | — | ◇ UNVERIFIED |
| MIMetal Industries, INC | Crystal River | FL | — | ◇ UNVERIFIED |
| MPMetal Pros | Wichita | KS | — | ◇ UNVERIFIED |
| MPMetals & Plastics INC | Longwood | FL | — | ◇ UNVERIFIED |
| MSMetropolitan Steel I/steelco | Sinking Spring | PA | — | ◇ UNVERIFIED |
| MMMetso Minerals | Milwaukee | WI | — | ◇ UNVERIFIED |
| MUMeyer Utility Structures | Clinton | IL | — | ◇ UNVERIFIED |
| MAMid America Steel Inc-fargo | Fargo | ND | — | ◇ UNVERIFIED |
| MAMiddle Atlantic Products, INC. | Fairfield | NJ | — | ◇ UNVERIFIED |
| MIMid-park INC - Mid-park Highway | Leitchfield | KY | — | ◇ UNVERIFIED |
| MSMid States Steel Products CO | Lexington | KY | — | ◇ UNVERIFIED |
| MSMidstate Steel, INC. | Macon | GA | — | ◇ UNVERIFIED |
| MMMidwest Machine Products INC | Golden | CO | — | ◇ UNVERIFIED |
| MIMiller/greeneville INC. | Greeneville | TN | — | ◇ UNVERIFIED |
| MFMillers Fab & Weld Corporation | Riverside | CA | — | ◇ UNVERIFIED |
| MFMillinocket Fabrication & Machine INC | Millinocket | ME | — | ◇ UNVERIFIED |
 Mills Manufacturing INC | Earlville | IA | — | ◇ UNVERIFIED |
| MUMinova USA INC | South Point | OH | — | ◇ UNVERIFIED |
| MMMisener Marine Construction, INC. | Tampa | FL | — | ◇ UNVERIFIED |
| MDMissouri Dry Dock & Repair CO | Cape Girardeau | MO | — | ◇ UNVERIFIED |
| MVMissouri Valley Steel Company | Sioux City | IA | — | ◇ UNVERIFIED |
| MCMjk Custom Fab and Coatings LLC | Ogden | UT | — | ◇ UNVERIFIED |
| MSMka Spray Service | Lawrence | MA | — | ◇ UNVERIFIED |
| MMMk Metal Products Enterprises INC | Mansfield | OH | — | ◇ UNVERIFIED |
| MWModern Welding CO of Kentucky INC | Hardin County | KY | — | ◇ UNVERIFIED |
| MMModine Mfg CO - Former Site of | Washington | IA | — | ◇ UNVERIFIED |
| MWMonarch Ware INC | Algoma | WI | — | ◇ UNVERIFIED |
| MRMowata Rice Drier INC - Southern Rice Drier & Storage CO | Rayne | LA | — | ◇ UNVERIFIED |
| MMMulberry Manufacturing CO | Mulberry | FL | — | ◇ UNVERIFIED |
| MPMulti-craft Plastics | Portland | OR | — | ◇ UNVERIFIED |
| MSMunster Steel Company | Munster | IN | — | ◇ UNVERIFIED |
| NCNai Cranes LLC | Woburn | MA | — | ◇ UNVERIFIED |
| NVNashoba Valley Structural | Lunenburg | MA | — | ◇ UNVERIFIED |
| NBNci Bldg Sys Inc/ambridge | Ambridge | PA | — | ◇ UNVERIFIED |
| NPNekoosa Packaging, Memphis Boxplant | Memphis | TN | — | ◇ UNVERIFIED |
