| 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 |
| NRNu Ray Metal Products INC | Puyallup | WA | 20–99 | ◐ LIKELY ACTIVE |
| NSNutech Steel INC | Ogden | UT | — | ◐ LIKELY ACTIVE |
| NLNuverde, LLC | Austin | TX | — | ◐ LIKELY ACTIVE |
| NFNuway Fab | Troy | IL | 1–19 | ◐ LIKELY ACTIVE |
| NINu-Way Industries, Inc. | Elk Grove Village | IL | 100–499 | ◐ LIKELY ACTIVE |
| NINystrom INC | Brooklyn Park | MN | — | ◐ LIKELY ACTIVE |
| OROak Ridge Industries, LLC | Washington | NC | 20–99 | ◐ LIKELY ACTIVE |
| OMO'Brien Metal Works | Clover | SC | 1–19 | ◐ LIKELY ACTIVE |
| OIOcci, INC. | Fulton | MO | — | ◐ LIKELY ACTIVE |
| OIOCTA Inc | Buckner | KY | 20–99 | ◐ LIKELY ACTIVE |
OEM Fabricators Inc. - Neillsville | Neillsville | WI | 20–99 | ◐ LIKELY ACTIVE |
OEM Fabricators Inc. - Phillips | Phillips | WI | 20–99 | ◐ LIKELY ACTIVE |
| OTOEM Tube Assemblies - Chipley | Chipley | FL | 20–99 | ◐ LIKELY ACTIVE |
| OTOEM Tube Assemblies - Clarksville | Clarksville | TN | 100–499 | ◐ LIKELY ACTIVE |
| OBOhio Bridge Manufacturing | Cambridge | OH | 20–99 | ◐ LIKELY ACTIVE |
| OFOhio Fabricators Company, Inc. | Coshocton | 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 |
| OCOJV Construction | Elk Grove | CA | 100–499 | ◐ LIKELY ACTIVE |
| ODOld Dominion Welding LLC | Franklin | VA | — | ▲ REPORTED CLOSED |
| OSOlmar Supply PMD | Livermore | CA | 1–19 | ◐ LIKELY ACTIVE |
| OFOlson Fabrication, Inc. | Algoma | WI | 20–99 | ◐ LIKELY ACTIVE |
| OCOlympia Chimney and Venting | Pittston | PA | 100–499 | ◐ LIKELY ACTIVE |
| OWOlympic Water Jet LLC | Poulsbo | WA | — | ◐ LIKELY ACTIVE |
| OCOMAMP Contech Engineered Solutions LLC | Wahoo | NE | 1–19 | ◐ LIKELY ACTIVE |
| OSOmega Steel, Inc. | Bloomingdale | GA | 20–99 | ◐ LIKELY ACTIVE |