| IIfab | Gastonia | NC | 100–499 | ◐ LIKELY ACTIVE |
| IIIfi International Fabrication Industries LLC | Lapeer | MI | — | ◐ LIKELY ACTIVE |
| ILIMIA, LLC Charleston | Goose Creek | SC | 1–19 | ◐ LIKELY ACTIVE |
| ILIMIA, LLC Rosemont Structural | Chesapeake | VA | 20–99 | ◐ LIKELY ACTIVE |
| IFImpact Fab | Holland | MI | 20–99 | ◐ LIKELY ACTIVE |
| ISIndustial Steel Constructors | Denham Springs | LA | 1–19 | ◐ LIKELY ACTIVE |
| ICIndustrial Connections & Solutions LLC | Cary | NC | — | ◐ LIKELY ACTIVE |
| IMIndustrial Metal Works LLC | Newtown | CT | — | ◐ LIKELY ACTIVE |
| IPIndustrial Panel Solutions, Inc. | Omaha | NE | 1–19 | ◐ LIKELY ACTIVE |
| IRIndustrial Resources, Inc. | Fairmont | WV | 20–99 | ◐ LIKELY ACTIVE |
| IRIndustrial Rigging Services of Central Texas | Hewitt | TX | 20–99 | ◐ LIKELY ACTIVE |
| ISIndustrial Steel South LLC | Rockledge | FL | 1–19 | ◐ LIKELY ACTIVE |
| IFInfrastructure Fabrication LLC | Bath | PA | — | ◐ LIKELY ACTIVE |
| IPIntegrated Power Services Liberty OH Service Center | Liberty Township | OH | 1–19 | ◐ LIKELY ACTIVE |
| IPIntegrated Power Services Switchgear Solutions Service Center | Tucson | AZ | 20–99 | ◐ LIKELY ACTIVE |
| IMInterior Mobile Welding & Services INC | Fairbanks | AK | — | ◐ LIKELY ACTIVE |
| IGIra G Steffy & Son, Inc. | Ephrata | PA | 100–499 | ◐ LIKELY ACTIVE |
| ISIron Sharpens Iron Welding & Fabricating, INC | Minneola | FL | — | ◐ LIKELY ACTIVE |
| ISIrwin Steel LLC | Justin | TX | 100–499 | ◐ LIKELY ACTIVE |
| IHIsland Hose & Seals, INC. | Deer Park | NY | — | ◐ LIKELY ACTIVE |
| ILIstanbul Logistics Aluminum Trading LLC | Vienna | VA | — | ◐ LIKELY ACTIVE |
| JJackson-Cook | Tallahassee | FL | 20–99 | ◐ LIKELY ACTIVE |
| JFJackson Field Welding Services, INC. | Tenino | WA | — | ◐ LIKELY ACTIVE |
| JMJackson Manufacturing Plant | Jackson | MI | 500+ | ◐ LIKELY ACTIVE |
| JPJacobs Precision Welding, INC | Lead | SD | — | ◐ LIKELY ACTIVE |
| JEJagg Electrical & Control, LLC | Lancaster | NY | 20–99 | ◐ LIKELY ACTIVE |
| JEJagg Electrical & Control, LLC - Tampa | Tampa | FL | 20–99 | ◐ LIKELY ACTIVE |
| JAJ and D Steel Fabrication and Repair, LP | Santa Maria | CA | 1–19 | ◐ LIKELY ACTIVE |
| JSJasper Steel Works LLC | Williamsport | PA | 1–19 | ◐ LIKELY ACTIVE |
| JTJasper TN | Jasper | TN | 100–499 | ◐ LIKELY ACTIVE |
| JSJeffords Steel and Engineering Company - Plattsburgh | Plattsburgh | NY | 20–99 | ◐ LIKELY ACTIVE |
| JSJeffords Steel and Engineering Company - Potsdam | Potsdam | NY | 20–99 | ◐ LIKELY ACTIVE |
| JJennmar | Cresson | PA | 20–99 | ◐ LIKELY ACTIVE |
| JCJennmar Corporation of Virginia, Inc. | Cedar Bluff | VA | 100–499 | ◐ LIKELY ACTIVE |
| JCJennmar Corporation of Virginia inc. Specialty Products | Cedar Bluff | VA | 20–99 | ◐ LIKELY ACTIVE |
| JSJennmar Specialty Cedar Bluff | Cedar Bluff | VA | 20–99 | ◐ LIKELY ACTIVE |
| JSJENNMAR Specialty Products - Louisville, LLC | Louisville | KY | 20–99 | ◐ LIKELY ACTIVE |
| JWJennmar West Kentucky | Earlington | KY | 20–99 | ◐ LIKELY ACTIVE |
| JTJf Technologies LLC | Morgan Hill | CA | — | ◐ LIKELY ACTIVE |
| JLJh.d.s., LLC | Lincoln Park | NJ | — | ◐ LIKELY ACTIVE |
| JKJ. Kozel & Son, Inc. dba Kozel Steel | Rochester | NY | 20–99 | ◐ LIKELY ACTIVE |
| JCJL Components | Kansas City | MO | 20–99 | ◐ LIKELY ACTIVE |
| JHJoel Hewatt Co., Inc. | Pittsburg | CA | 20–99 | ◐ LIKELY ACTIVE |
| JHJohn H Carter CO INC | Baton Rouge | LA | — | ◐ LIKELY ACTIVE |
| JTJ Talley Holding CORP | San Jacinto | CA | — | ◐ LIKELY ACTIVE |
| JCJ.t.fennell Co., INC. | Chillicothe | IL | 500+ | ◐ LIKELY ACTIVE |
| JFJ.T. Fennell Company Peoria | Peoria | IL | 20–99 | ◐ LIKELY ACTIVE |
| JIJtn, INC. | Livingston | MT | — | ◐ LIKELY ACTIVE |
| KWK1 Welding & Fabercation LLC | Belen | NM | — | ◐ LIKELY ACTIVE |
| KVKaiva Vertical Lift, LLC | Ivins | UT | — | ◐ LIKELY ACTIVE |