| KPKeystone Profiles LTD | Beaver Falls | PA | 20–99 | ◐ LIKELY ACTIVE |
| KKiswire | Pine Bluff | AR | 100–499 | ◐ LIKELY ACTIVE |
| KIKWM, Inc. dba Stainless Structurals Works | Conroe | TX | 20–99 | ◐ LIKELY ACTIVE |
| KSKyoei Steel America, LLC | Vinton | TX | 100–499 | ◐ LIKELY ACTIVE |
| LFLabelleco fab | Beaumont | TX | 100–499 | ◐ LIKELY ACTIVE |
| LFLahti Fabrication Inc | Alger | MI | 20–99 | ◐ LIKELY ACTIVE |
| LHLapham - Hickey Steel | Fountain Inn | SC | 20–99 | ◐ LIKELY ACTIVE |
| LSLapham-Hickey Steel | Little Canada | MN | 20–99 | ◐ LIKELY ACTIVE |
| LSLapham-Hickey Steel Corp | Madison | IL | 20–99 | ◐ LIKELY ACTIVE |
| LOLatrobe Operations | Latrobe | PA | 100–499 | ◐ LIKELY ACTIVE |
| LFLaX Fabricating LTD - Spring Grove MN | Spring Grove | MN | 20–99 | ◐ LIKELY ACTIVE |
| LFLaX Fabricating LTD - Westby WI | Westby | WI | 20–99 | ◐ LIKELY ACTIVE |
| LELevy Environmental Services Company dba Brandenburg Mill Service | Brandenburg | KY | 20–99 | ◐ LIKELY ACTIVE |
| LELevy Environmental Services Company dba Butler Mill Service | Butler | IN | 20–99 | ◐ LIKELY ACTIVE |
| LELevy Environmental Services Company dba Charleston Mill Service | Huger | SC | 20–99 | ◐ LIKELY ACTIVE |
| LELevy Environmental Services Company dba Columbia City Mill Services | Columbia City | IN | 20–99 | ◐ LIKELY ACTIVE |
| LELevy Environmental Services Company dba Fulton Mill Service | Delta | OH | 20–99 | ◐ LIKELY ACTIVE |
| LELevy Environmental Services Company dba Levy Big River | Osceola | AR | 100–499 | ◐ LIKELY ACTIVE |
| LELevy Environmental Services Company dba Levy Gallatin Mill Service | Ghent | KY | 20–99 | ◐ LIKELY ACTIVE |
| LELevy Environmental Services Company dba Levy NYS Mill Service | Blytheville | AR | 20–99 | ◐ LIKELY ACTIVE |
| LELevy Environmental Services Company dba Levy Texas Mill Services | Sinton | TX | 20–99 | ◐ LIKELY ACTIVE |
| LELevy Environmental Services Company dba SeaTac Steel Mill and Recycling Services | Seattle | WA | 1–19 | ◐ LIKELY ACTIVE |
| LOLockport Operations | Loc | NY | 20–99 | ◐ LIKELY ACTIVE |
| LLLSM - Latrobe | Latrobe | PA | 500+ | ◐ LIKELY ACTIVE |
| LSLSM - Sandy Creek | Franklin | PA | 20–99 | ◐ LIKELY ACTIVE |
| MMMarion Manufacturing, Inc. | Marion | KS | 20–99 | ◐ LIKELY ACTIVE |
| MBMaster Builders & Erectors CORP | Folcroft | PA | — | ◐ LIKELY ACTIVE |
| MSMaverick Steel Group, LLC | Hendersonville | NC | — | ◐ LIKELY ACTIVE |
| MFMedford Fabrication | Medford | OR | 1–19 | ◐ LIKELY ACTIVE |
| MJMedtronic JAXs | Jacksonville | FL | 500+ | ◐ LIKELY ACTIVE |
| MSMedtronic Santa Clara | Santa Clara | CA | 20–99 | ◐ LIKELY ACTIVE |
| MMMemphis Mill Service Company | Memphis | TN | 20–99 | ◐ LIKELY ACTIVE |
| MMetalac | Latrobe | PA | 1–19 | ◐ LIKELY ACTIVE |
| MUMetals USA- Wooster | Wooster | OH | 20–99 | ◐ LIKELY ACTIVE |
| MOMidland Operations | Midland | PA | 1–19 | ◐ LIKELY ACTIVE |
| MPMidwest Plant | Portage | IN | 500+ | ◐ LIKELY ACTIVE |
| MRMidwest Roll Forming & Mfg | Pierceton | IN | 100–499 | ◐ LIKELY ACTIVE |
| MSMillennium Steel Service | Princeton | IN | 20–99 | ◐ LIKELY ACTIVE |
| MMMisa Metal Processing Forest, Mississippi | Forest | MS | 1–19 | ◐ LIKELY ACTIVE |
| MMMisa Metal Processing Louisville, Kentucky | Louisville | KY | 20–99 | ◐ LIKELY ACTIVE |
| MMMisa Metal Processing Portland, Tennessee | Portland | TN | 20–99 | ◐ LIKELY ACTIVE |
| MAMobis America Inc dba Mobis Alabama LLC | Montgomery | AL | 500+ | ◐ LIKELY ACTIVE |
| MOMonaca Operations | Monaca | PA | 100–499 | ◐ LIKELY ACTIVE |
| MMMonarch Materials Group, Inc. | Adel | IA | 20–99 | ◐ LIKELY ACTIVE |
| MSMonarch Steel Company, Inc. | Cleveland | OH | 20–99 | ◐ LIKELY ACTIVE |
| MSMonarch Steel of Alabama, Inc. | Decatur | AL | 20–99 | ◐ LIKELY ACTIVE |
| MCMoody Construction Services, Inc. | Duette | FL | 20–99 | ◐ LIKELY ACTIVE |
| NNARSTCO-Midlothian | Midlothian | TX | 20–99 | ◐ LIKELY ACTIVE |
| NGNational Galvanizing | Monroe | MI | 100–499 | ◐ LIKELY ACTIVE |
| NHNatrona Heights Operations (NHO) | Natrona Heights | PA | 100–499 | ◐ LIKELY ACTIVE |