| MBMadden Bolt Corporation KERMIER | Hockley | TX | 100–499 | ◐ LIKELY ACTIVE |
| MPMainstream Packaging, Inc. | Lebanon | KY | 20–99 | ◐ LIKELY ACTIVE |
| MMMarcon Metal USA Inc | Ferndale | WA | 20–99 | ◐ LIKELY ACTIVE |
| MEMast Enterprises Equipment LLC | South Boston | VA | — | ◐ LIKELY ACTIVE |
| MRMaxxim Rebuild Co., LLC dba Maxxim Manufacturing | Bluefield | WV | 100–499 | ◐ LIKELY ACTIVE |
| MSMcCombs Steel Company - Winston | Statesville | NC | 1–19 | ◐ LIKELY ACTIVE |
| MMcHard | Houston | TX | 100–499 | ◐ LIKELY ACTIVE |
| MWMckee Welding & Fabrication LLC | Beaufort | SC | — | ◐ LIKELY ACTIVE |
| MMcMinville | Rock Island | TN | 20–99 | ◐ LIKELY ACTIVE |
| MIMdj Industrial LLC | Houston | TX | — | ◐ LIKELY ACTIVE |
| MWMelvin Wrought Iron Inc - Main Shop | Ontario | CA | 20–99 | ◐ LIKELY ACTIVE |
| MFMenomonee Falls Location | Menomonee Falls | WI | 20–99 | ◐ LIKELY ACTIVE |
| MCMetal City Fab, LLC | Warren | MI | 20–99 | ◐ LIKELY ACTIVE |
| MOMetalcrafters of Wayne County | Goldsboro | NC | 20–99 | ◐ LIKELY ACTIVE |
| MFMetal Fabrication LLC | Evansville | IN | 20–99 | ◐ LIKELY ACTIVE |
| MMMetal Masters of Florida Inc | Lake City | FL | 1–19 | ◐ LIKELY ACTIVE |
| MSMetalworking Solutions, Inc. | Chattanooga | TN | 100–499 | ◐ LIKELY ACTIVE |
| MSMetro Site Fabricators, LLC | Commerce | GA | 20–99 | ◐ LIKELY ACTIVE |
| MFMga Fab | Akron | NY | 20–99 | ◐ LIKELY ACTIVE |
| MSMica Steelworks, INC | Fort Worth | TX | — | ◐ LIKELY ACTIVE |
| MIMid Island Steel Corp | Medford | NY | 20–99 | ◐ LIKELY ACTIVE |
| MMMid-States Material Handling & Fabrication, Inc. | Nevada | IA | 20–99 | ◐ LIKELY ACTIVE |
| MMMilling Machinery, Inc (El Centro Shop) | El Centro | CA | 20–99 | ◐ LIKELY ACTIVE |
| MMMilling Machinery, Inc. (Mesa Shop) | Mesa | AZ | 20–99 | ◐ LIKELY ACTIVE |
| MMillington | Millington | TN | 1–19 | ◐ LIKELY ACTIVE |
| MSMilton Steel Company | Milton PA | PA | 20–99 | ◐ LIKELY ACTIVE |
| MSMiscellaneous Steel Industries, Inc. | Kyle | TX | 20–99 | ◐ LIKELY ACTIVE |
| MCMission Complete Metal Worx LLC | Warner Robins | GA | — | ◐ LIKELY ACTIVE |
| MAMJ Associates Philadelphia | Philadelphia | PA | 20–99 | ◐ LIKELY ACTIVE |
| MMModern Metals | Ashland | KY | 20–99 | ◐ LIKELY ACTIVE |
| MWModern Welding Company of Kentucky, Inc. (Madisonville) | Madisonville | KY | 20–99 | ◐ LIKELY ACTIVE |
| MMMonarch Machine & Tool Co., INC. | Pasco | WA | — | ◐ LIKELY ACTIVE |
| MMMoore Metal Works, LLC | Evansville | IN | 20–99 | ◐ LIKELY ACTIVE |
| MSMorgan Steel Texas, LLC | Greenville | TX | 20–99 | ◐ LIKELY ACTIVE |
| MWMorningstar Welding, LLC | Poolesville | MD | — | ◐ LIKELY ACTIVE |
| MIMultiMetal Inc, dba Moore & Morford II | Greensburg | PA | 20–99 | ◐ LIKELY ACTIVE |
| Mmunster1501 | Hammond | IN | 20–99 | ◐ LIKELY ACTIVE |
| NCNativewest CORP | West Linn | OR | — | ◐ LIKELY ACTIVE |
| NNc01-yis | Jacksonville | NC | 1–19 | ◐ LIKELY ACTIVE |
| NNc03-yis | Jacksonville | NC | 1–19 | ◐ LIKELY ACTIVE |
| NCNc Carports and Garages LLC | Elkin | NC | — | ◐ LIKELY ACTIVE |
| NMNew Millennium Building Systems, LLC. - Columbia | Columbia | SC | 20–99 | ◐ LIKELY ACTIVE |
| NMNew Millennium Building Systems, LLC. - Fallon | Fallon | NV | 100–499 | ◐ LIKELY ACTIVE |
| NMNew Millennium Building Systems, LLC. - Northwest Arkansas Engineering | Rogers | AR | 20–99 | ◐ LIKELY ACTIVE |
| NBNext Build Steel LLC | Virginia | MN | — | ◐ LIKELY ACTIVE |
| NNiles | Niles | OH | 20–99 | ◐ LIKELY ACTIVE |
| NBNiles Building Products Company - Florida | Jacksonville | FL | 20–99 | ◐ LIKELY ACTIVE |
| NBNiles Building Products Company - Ohio | Niles | OH | 1–19 | ◐ LIKELY ACTIVE |
| NBNiles Building Products Company - Texas | Grand Prairie | TX | 1–19 | ◐ LIKELY ACTIVE |
| NSNimsgern Steel Corp. | Minocqua | WI | 20–99 | ◐ LIKELY ACTIVE |
| NINix Industrial - Fairfield, OH | Farifield | OH | 1–19 | ◐ LIKELY ACTIVE |
| NINix Industrial - Frontage Road | Poseyville | IN | 20–99 | ◐ LIKELY ACTIVE |
| NINix Industrial - Main Street | Poseyville | IN | 20–99 | ◐ LIKELY ACTIVE |
| NINix Industrial - Rockport, IN | Rockport | IN | 20–99 | ◐ LIKELY ACTIVE |
| NGNorfork General Industries, Inc | Norfork | AR | 20–99 | ◐ LIKELY ACTIVE |
| NSNorlen - Schofield | Schofield | WI | 100–499 | ◐ LIKELY ACTIVE |
| NANorth American Manufacturing Corp. | Maspeth | NY | 1–19 | ◐ LIKELY ACTIVE |
| NHNorthern Horizons Solway, Inc | Solway | MN | 100–499 | ◐ LIKELY ACTIVE |
| NSNorthern Steel Services, L.L.C. | Montrose | MI | 20–99 | ◐ LIKELY ACTIVE |
| NTNorth Texas Pressure Vessels, Inc. | Mineral Wells | TX | 20–99 | ◐ LIKELY ACTIVE |
| NWNuark Warehouse & Logistics | Blytheville | AR | 20–99 | ◐ LIKELY ACTIVE |
| NHNucor Harris Rebar Mid-Atlantic LLC (Baltimore Facility) | Baltimore | MD | 20–99 | ◐ LIKELY ACTIVE |
| NHNucor Harris Rebar Northeast LLC (Bethlehem Facility) | Bethlehem | PA | 20–99 | ◐ LIKELY ACTIVE |
| NHNucor Harris Rebar Northeast LLC (Canaan Facility) | Canaan | NH | 20–99 | ◐ LIKELY ACTIVE |
| NHNucor Harris Rebar Northeast LLC (Pawtucket Facility) | Pawtucket | RI | 20–99 | ◐ LIKELY ACTIVE |
| NHNucor Harris Rebar Northeast LLC (South Deerfield Facility) | South Deerfield | MA | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Midwest LLC Bourbonnais, Illinois | Bourbonnais | IL | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Midwest LLC Lansing, Michigan | Lansing | MI | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Midwest LLC Marion, Ohio | Marion | OH | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Midwest LLC Mooresville, Indiana | Mooresville | IN | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Midwest LLC - Newton Iowa | Newton | IA | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Midwest LLC - Roberts Wisonsin | Roberts | WI | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Midwest LLC Rockford, Illinois | Rockford | IL | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Midwest LLC - Sedalia Missouri | Sedalia | MO | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Midwest LLC - St. Louis Missouri | Saint Louis | MO | 1–19 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Services Center Corp | Fort Wayne | IN | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Southcentral LLC - Dallas Texas | Dallas | TX | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Southcentral LLC - Houston Texas | Dayton | TX | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Southcentral LLC - Jackson Mississippi | Flowood | MS | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Southcentral LLC - Jewett Texas | Jewett | TX | 20–99 | ◐ LIKELY ACTIVE |
| NRNucor Rebar Fabrication Southcentral LLC - Slidell Louisiana | Slidell | LA | 20–99 | ◐ LIKELY ACTIVE |
| NSNucor Skyline | Huger | SC | 20–99 | ◐ LIKELY ACTIVE |
| NTNucor Towers and Structures Indiana | New Ross | IN | 100–499 | ◐ LIKELY ACTIVE |
| NTNucor Towers & Structures Inc | West Hazleton | PA | 100–499 | ◐ LIKELY ACTIVE |
| NDNucor (Vulcraft Division) | Saint Joe | IN | 100–499 | ◐ LIKELY ACTIVE |
| NENuena Enterprises, LLC | Houston | TX | — | ◐ LIKELY ACTIVE |
| NINuno Iron & Mfg. Inc. | King City | CA | 20–99 | ◐ LIKELY ACTIVE |
| NLNuverde, LLC | Austin | TX | — | ◐ LIKELY ACTIVE |
| NFNuway Fab | Troy | IL | 1–19 | ◐ LIKELY ACTIVE |
| OMO'Brien Metal Works | Clover | SC | 1–19 | ◐ LIKELY ACTIVE |
| OIOcci, INC. | Fulton | MO | — | ◐ LIKELY ACTIVE |
| OBOhio Bridge Manufacturing | Cambridge | OH | 20–99 | ◐ LIKELY ACTIVE |
| OMOhio Moulding | Wickliffe | OH | 20–99 | ◐ LIKELY ACTIVE |
| OSOhio Steel Industries Inc - Structural Division | Pataskala | OH | 20–99 | ◐ LIKELY ACTIVE |
| OSOmega Steel, Inc. | Bloomingdale | GA | 20–99 | ◐ LIKELY ACTIVE |
| OWOptimized Welding Services LLC | El Paso | TX | — | ◐ LIKELY ACTIVE |
| OTOregon Trail Fabrication LLC | Salem | OR | — | ◐ LIKELY ACTIVE |
| OWOscar's Welding Svcs LLC | Odessa | TX | — | ◐ LIKELY ACTIVE |
| OOttawa | Ottawa | KS | 20–99 | ◐ LIKELY ACTIVE |
| OOwensboro | Owensboro | KY | 20–99 | ◐ LIKELY ACTIVE |