| NNNewport News Shipbldg Oyster Pt Industrial Pk Opip | Newport News | VA | — | ◇ UNVERIFIED |
| NNNewport News Shipbuilding Oakland Industrial Oip | Newport News | VA | — | ◇ UNVERIFIED |
| NSNew Steel, INC. | Omaha | NE | — | ◇ UNVERIFIED |
| NRNexGen Rebar LLC | Harrisonburg | VA | — | ◇ UNVERIFIED |
| NGNext Generation Construction, LLC | New York | NY | — | ◇ UNVERIFIED |
| NLNext Level Metal | Baldwin | IL | — | ◇ UNVERIFIED |
| NGNGM Glass Metals, LLC | Woodbridge | VA | — | ◇ UNVERIFIED |
| NFNiagara Frontier Custom Fabrication, INC. | Buffalo | NY | — | ◇ UNVERIFIED |
| NPNichols Propeller Company | Greenville | MS | — | ◇ UNVERIFIED |
| NMNick's Metal Fabricating & Sons, INC. | Chicago | IL | — | ◇ UNVERIFIED |
| NWNiermann Weeks Company, INC | Millersville | MD | — | ◇ UNVERIFIED |
| NMNix Metals Fabrication Building Expansion | Poseyville | IN | — | ◇ UNVERIFIED |
| NJN J Mccutchen INC | Stockton | CA | — | ◇ UNVERIFIED |
| NCNooter Corporation | Saint Louis | MO | — | ◇ UNVERIFIED |
 North Alabama Fabricating Company, INC. | Glen Allen | AL | — | ◇ UNVERIFIED |
| North Alabama Fabricating Company, INC. | Cullman | AL | — | ◇ UNVERIFIED |
| NCNorth Chicago Iron Works, INC. | North Chicago | IL | — | ◇ UNVERIFIED |
| NCNorth Coast Tool, INC. | Erie | PA | — | ◇ UNVERIFIED |
| NSNortheast Sheet Metal LLC | Hoboken | NJ | — | ◇ UNVERIFIED |
| NCNorthern California Framing & Carpentry, INC. | Ripon | CA | — | ◇ UNVERIFIED |
| NMNorthern Metal Fab INC | Baldwin | WI | — | ◇ UNVERIFIED |
| NONorthern Oregon Fabrication LLC | North Plains | OR | — | ◇ UNVERIFIED |
| NSNorthern Screw Machine Company INC | Saint Paul | MN | — | ◇ UNVERIFIED |
 Northland Machine INC | Cohasset | MN | — | ◇ UNVERIFIED |
| NSNorth Second Street Smithfield LLC Dba Con-quip | Burlington | KY | — | ◇ UNVERIFIED |
| NSNorth Shore Steel Co., INC. | Lynn | MA | — | ◇ UNVERIFIED |
| NSNorthshore Steel INC | Two Harbors | MN | — | ◇ UNVERIFIED |
| NSNorth Star Fabricators, INC. | Pocatello | ID | — | ◇ UNVERIFIED |
| NTNorth Texas Steel | Fort Worth | TX | — | ◇ UNVERIFIED |
| NANorthwest Aluminum Trailers INC | Roseburg | OR | — | ◇ UNVERIFIED |
| NSNorthwest Steel Fab INC Deer Park | Deer Park | WA | — | ◇ UNVERIFIED |
| NSNorthwest Structural Services INC | Portland | OR | — | ◇ UNVERIFIED |
| NSNorthwest Structural Services INC | Portland | OR | — | ◇ UNVERIFIED |
| NSNorthwest Structural Services INC | Portland | OR | — | ◇ UNVERIFIED |
| NTNorthwest Thermal Systems INC | Estacada | OR | — | ◇ UNVERIFIED |
| NPNovel Precision Machine LLC | Lyndon | KY | — | ◇ UNVERIFIED |
| NSNowlin Steelcraft, INC. | Hampton | VA | — | ◇ UNVERIFIED |
| NNucor | Norfolk | NE | — | ◇ UNVERIFIED |
| NHNucor Harris Rebar Jackson LLC | Flowood | MS | — | ◇ UNVERIFIED |
| NHNucor Harris Rebar - Zellwood | Zellwood | FL | — | ◇ UNVERIFIED |
| NRNucor Rebar Fabrication Northeast LLC | Pawtucket | RI | — | ◇ UNVERIFIED |
| NRNucor Rebar Fabrication Southwest INC | Lathrop | CA | — | ◇ UNVERIFIED |
| NSNucor Skyline | Armorel | AR | — | ◇ UNVERIFIED |
| NTNucor Towers and Structures | New Ross | IN | — | ◇ UNVERIFIED |
| NTNucor Towers & Structures | Crawfordsville | IN | — | ◇ UNVERIFIED |
| NVNucor Vulcraft Group | San Antonio | TX | — | ◇ UNVERIFIED |
| NVNucor Vulcraft - St. Joe Division | Saint Joe | IN | — | ◇ UNVERIFIED |
| NSNuEra Steel LLC | Viborg | SD | — | ◇ UNVERIFIED |
| NCNueva Castilla Iron Works, INC. | San Francisco | CA | — | ◇ UNVERIFIED |
| NRNufab Rebar-slidell, LLC | Alexandria | LA | — | ◇ UNVERIFIED |
| NNNumber Nine, L.l.c. | Lk Havasu Cty | AZ | — | ◇ UNVERIFIED |
| NFNusteel Fabricators, INC. | Childersburg | AL | — | ◇ UNVERIFIED |
| NSNWA Steel Co LLC | Siloam Springs | AR | — | ◇ UNVERIFIED |
| OIOakdale Iron Works, INC. | Oakdale | PA | — | ◇ UNVERIFIED |
| OFOberlin Filter Company | Pewaukee | WI | — | ◇ UNVERIFIED |
| OCObie Construction, INC. | Eugene | OR | — | ◇ UNVERIFIED |
| OIOcci INC. Wwtp | Fulton | MO | — | ◇ UNVERIFIED |
 Occupational Development Center INC Dba Custom Pro | Bemidji | MN | — | ◇ UNVERIFIED |
| OSOcean Steel Corporation | Binghamton | NY | — | ◇ UNVERIFIED |
| OBOeg Building Materials INC. | Matawan | NJ | — | ◇ UNVERIFIED |
| OFOem Fabricators INC | Neillsville | WI | — | ◇ UNVERIFIED |
| OSOesterlings Sandblasting/butler | Butler | PA | — | ◇ UNVERIFIED |
| OAOgden Art Metal INC. | Murray | UT | — | ◇ UNVERIFIED |
| OOgletree's | Saint Helena | CA | — | ◇ UNVERIFIED |
| OCOglivie Company INC the | Astoria | OR | — | ◇ UNVERIFIED |
| OHO H I Company | Stockton | CA | — | ◇ UNVERIFIED |
| OCOhi Company | Stockton | CA | — | ◇ UNVERIFIED |
| OSOhio Steel Industries (0145000318) | Pataskala | OH | — | ◇ UNVERIFIED |
| OSOhio Steel Industries, INC. | Summit Station | OH | — | ◇ UNVERIFIED |
| OVOhio Valley Fabrication and Energy INC. | Wheeling | WV | — | ◇ UNVERIFIED |
| OIOiw, INC. | Pelham | AL | — | ◇ UNVERIFIED |
| OLOiw LLC | Oakdale | PA | — | ◇ UNVERIFIED |
| OKO & K American CORP. | Chicago | IL | — | ◇ UNVERIFIED |
| OBOld Bridge Metal Fabrication Inc. | Riverside | CA | — | ◇ UNVERIFIED |
| OIOldcastle Infrastructure - Azusa 10th | Azusa | CA | — | ◇ UNVERIFIED |
| OIOldcastle Infrastructure - Azusa Dalou | Azusa | CA | — | ◇ UNVERIFIED |
| OCOlson & Company Steel | Fresno | CA | — | ◇ UNVERIFIED |
| OSOlson Steel | San Leandro | CA | — | ◇ UNVERIFIED |
| OTOlympus Technologies Incorporated | Eugene | OR | — | ◇ UNVERIFIED |
| ONOmega Natchiq New Iberia Facility | New Iberia | LA | — | ◇ UNVERIFIED |
| OSOmega Steel Products, INC | Jemison | AL | — | ◇ UNVERIFIED |
| OMO & M Fabricators, LLC | Pensacola | FL | — | ◇ UNVERIFIED |
| OIOmni Industrial Services | Buffalo | WV | — | ◇ UNVERIFIED |
| OSOne Source Systems LLC | Vicksburg | MS | — | ◇ UNVERIFIED |
| OTOn Time Fab INC | Saint Joseph | KY | — | ◇ UNVERIFIED |
| OFOpc Fabrication and Equipment, INC. (fn) | Phoenix | AZ | — | ◇ UNVERIFIED |
| OSOrange State Steel | Bartow | FL | — | ◇ UNVERIFIED |
| OSOrange State Steel Construction, INC | Pinellas Park | FL | — | ◇ UNVERIFIED |
| OSOrange State Steel Construction, INC. | Riverview | FL | — | ◇ UNVERIFIED |
| OCOrco Construction Supply | Bloomington | CA | — | ◇ UNVERIFIED |
| ODOreco Duct System INC | Baldwin Park | CA | — | ◇ UNVERIFIED |
| OIOregon Iron Works Hidden Way | Vancouver | WA | — | ◇ UNVERIFIED |
| OIOregon Iron Works INC 3001 | Vancouver | WA | — | ◇ UNVERIFIED |
| OPOregon Pacific Structural Fabrication, LLC | Mulino | OR | — | ◇ UNVERIFIED |
| OTOrganic Transit INC. | Durham | NC | — | ◇ UNVERIFIED |
| OMOrion Marine Construction, INC | Tampa | FL | — | ◇ UNVERIFIED |
| OIOrlando Iron Works | Paterson | NJ | — | ◇ UNVERIFIED |
| OMOrnamental Metalworks INC | Decatur | IL | — | ◇ UNVERIFIED |
| OWOsborne Welding, INC. | Hampton | VA | — | ◇ UNVERIFIED |
| OAOshkosh Aerotech - Jetway Systems | Ogden | UT | — | ◇ UNVERIFIED |
