| MSMidland Steel | Wathena | KS | Fabricated Metal Product Manufacturing332312 | 20-99 | ◐ LIKELY ACTIVE |
| MFMid-west Forge CORP | Cleveland | OH | Fabricated Metal Product Manufacturing332111 | 100-499 | ◐ LIKELY ACTIVE |
| MMMilbank Manufacturing CO | Kansas City | MO | Fabricated Metal Product Manufacturing332439 | 100-499 | ◐ LIKELY ACTIVE |
| MMMilbank Manufacturing CO | El Dorado | AR | Fabricated Metal Product Manufacturing332439 | 100-499 | ◐ LIKELY ACTIVE |
| MMMilbank Manufacturing Company | Concordia | MO | Fabricated Metal Product Manufacturing332116 | 100-499 | ◐ LIKELY ACTIVE |
| MTMillennium Technologies LLC | Plymouth | WI | Fabricated Metal Product Manufacturing332710 | — | ◐ LIKELY ACTIVE |
| MMMill Masters, INC. | Jackson | TN | Fabricated Metal Product Manufacturing332997 | 20-99 | ◐ LIKELY ACTIVE |
| MPMills Products, INC. | Athens | TN | Primary Metal Manufacturing331221 | 100-499 | ◐ LIKELY ACTIVE |
| MPMilwaukee Plating CO | Milwaukee | WI | Fabricated Metal Product Manufacturing332810 | 20-99 | ◐ LIKELY ACTIVE |
| MCMnp CORP | Utica | MI | Primary Metal Manufacturing331222 | 100-499 | ◐ LIKELY ACTIVE |
| MDModern Door CORP | Walkerton | IN | Fabricated Metal Product Manufacturing332321 | 100-499 | ◐ LIKELY ACTIVE |
| MWModern Welding Company of Florida | Orlando | FL | Fabricated Metal Product Manufacturing332312 | 20-99 | ◐ LIKELY ACTIVE |
| MWModern Welding CO of Iowa INC | Burlington | IA | Fabricated Metal Product Manufacturing332312 | 20-99 | ◐ LIKELY ACTIVE |
| MPModineer Plant 7 | Saint Peters | MO | Fabricated Metal Product Manufacturing332322 | 100-499 | ◐ LIKELY ACTIVE |
Modine Manufacturing Company Joplin | Joplin | MO | Fabricated Metal Product Manufacturing332313 | 100-499 | ◐ LIKELY ACTIVE |
| MMMonogram Metals, INC. | Byesville | OH | Fabricated Metal Product Manufacturing332312 | 20-99 | ◐ LIKELY ACTIVE |
| MOMonotech of Mississippi, Fulton | Fulton | MS | Fabricated Metal Product Manufacturing332312 | 20-99 | ◐ LIKELY ACTIVE |
| MIMoog INC | East Aurora | NY | Fabricated Metal Product Manufacturing332912 | — | ◐ LIKELY ACTIVE |
| MMMoore & Morford INC | Greensburg | PA | Fabricated Metal Product Manufacturing332312 | 20-99 | ◐ LIKELY ACTIVE |
| MOMorgan Ohare INC | Addison | IL | Fabricated Metal Product Manufacturing332811 | 20-99 | ◐ LIKELY ACTIVE |
| MIMorton Industries LLC | Morton | IL | Primary Metal Manufacturing331210 | 100-499 | ◐ LIKELY ACTIVE |
| MPMtd Products | Verona | MS | Fabricated Metal Product Manufacturing332999 | 500+ | ◐ LIKELY ACTIVE |
| MCMueller CO Gas Prods Div | Brownsville | TX | Fabricated Metal Product Manufacturing332911 | 20-99 | ◐ LIKELY ACTIVE |
| MFMueller Fittings CO INC | Covington | TN | Primary Metal Manufacturing331420 | 20-99 | ◐ LIKELY ACTIVE |
| MRMueller Refrigeration | Hartsville | TN | Fabricated Metal Product Manufacturing332911 | 100-499 | ◐ LIKELY ACTIVE |
| NINagalv-ohio, INC | Canton | OH | Fabricated Metal Product Manufacturing332812 | 20-99 | ◐ LIKELY ACTIVE |
| NONational Oilwell Varco LP | Houma | LA | Fabricated Metal Product Manufacturing332710 | 20-99 | ◐ LIKELY ACTIVE |
| NENew England Union Co., INC. | West Warwick | RI | Primary Metal Manufacturing331528 | 20-99 | ◐ LIKELY ACTIVE |
| NJNew Jersey Galvanizing & Tinning Works | Newark | NJ | Fabricated Metal Product Manufacturing332812 | 20-99 | ◐ LIKELY ACTIVE |
| NWNewsouth Window Solutions LLC | Tampa | FL | Plastics and Rubber Products Manufacturing326199 | 100-499 | ◐ LIKELY ACTIVE |
| NINibrock, INC. | Chunchula | AL | Fabricated Metal Product Manufacturing332212 | 20-99 | ◐ LIKELY ACTIVE |
Nichols Manufacturing INC | Hollister | CA | Fabricated Metal Product Manufacturing332710 | — | ◐ LIKELY ACTIVE |
| NPNichols Portland, LLC | Portland | ME | Fabricated Metal Product Manufacturing332117 | 100-499 | ◐ LIKELY ACTIVE |
| NANisshinbo Automotive Manufacturing, INC. | Covington | GA | Fabricated Metal Product Manufacturing332813 | 100-499 | ◐ LIKELY ACTIVE |
| NPNobert Plating CO | Chicago | IL | Fabricated Metal Product Manufacturing332813 | 20-99 | ◐ LIKELY ACTIVE |
| NPNobert Plating CO | Chicago | IL | Fabricated Metal Product Manufacturing332813 | 20-99 | ◐ LIKELY ACTIVE |
| NINorlen Incorporated | Schofield | WI | Fabricated Metal Product Manufacturing332313 | — | ◐ LIKELY ACTIVE |
| NANorth American Galvanizing Co-kansas City | Kansas City | MO | Fabricated Metal Product Manufacturing332812 | 20-99 | ◐ LIKELY ACTIVE |
| NANorth American Galvanizing Company Tulsa Plant 1 | Tulsa | OK | Fabricated Metal Product Manufacturing332812 | 20-99 | ◐ LIKELY ACTIVE |
| NANorthland Aluminum Products INC | Saint Louis Park | MN | Plastics and Rubber Products Manufacturing326199 | 100-499 | ◐ LIKELY ACTIVE |
| NLNovae LLC | Louisiana | MO | Fabricated Metal Product Manufacturing332117 | 1-19 | ◐ LIKELY ACTIVE |
| NCNsk Corporation | Clarinda | IA | Fabricated Metal Product Manufacturing332991 | 100-499 | ◐ LIKELY ACTIVE |
| NCNtn-bower CORP | Hamilton | AL | Fabricated Metal Product Manufacturing332991 | 100-499 | ◐ LIKELY ACTIVE |
| NBNucor Building Systems Ut LLC | Brigham City | UT | Fabricated Metal Product Manufacturing332311 | 100-499 | ◐ LIKELY ACTIVE |
| NCNucor Corporation Vulcraft Division | Fort Payne | AL | Fabricated Metal Product Manufacturing332311 | 100-499 | ◐ LIKELY ACTIVE |
| NSNxedge San Carlos | San Carlos | CA | Fabricated Metal Product Manufacturing332813 | 20-99 | ◐ LIKELY ACTIVE |
| OSOklahoma Steel & Wire Co., INC. | Madill | OK | Fabricated Metal Product Manufacturing332618 | 100-499 | ◐ LIKELY ACTIVE |
| OSOlympic Systems CORP | Winchester | MA | Fabricated Metal Product Manufacturing332721 | 20-99 | ◐ LIKELY ACTIVE |
| OOOrchid Orthopedic Solutions LLC | Holt | MI | Fabricated Metal Product Manufacturing332112 | 100-499 | ◐ LIKELY ACTIVE |
Ortram Aluminum Systems CORP | Barranquitas | PR | Fabricated Metal Product Manufacturing332321 | — | ◐ LIKELY ACTIVE |