| IIndianapolis | Indianapolis | IN | 100–499 | ◐ LIKELY ACTIVE |
| ICIndian Creek Fabricators INC. | Tipp City | OH | — | ◐ LIKELY ACTIVE |
| IHInduction Heat Treating Seymour Corp | Seymour | IN | 1–19 | ◐ LIKELY ACTIVE |
| IHInduction Heat Treating Waukesha Corp. | Waukesha | WI | 1–19 | ◐ LIKELY ACTIVE |
Industrial Automation LLC - Alabama | Montgomery | AL | 1–19 | ◐ LIKELY ACTIVE |
| ICIndustrial Coating Services INC. | Stacy | MN | — | ◐ LIKELY ACTIVE |
| ICIndustrial Connections & Solutions LLC | Cary | NC | — | ◐ LIKELY ACTIVE |
| ICIndustrial Consortium INC | Lancaster | PA | — | ◐ LIKELY ACTIVE |
| IDIndustrial Design Manufacturing LLC | Mount Sterling | KY | — | ◐ LIKELY ACTIVE |
| IEIndustrial Engineering Manufacturing Co, INC | Foxboro | MA | — | ▲ REPORTED CLOSED |
| IFIndustrial Fabrication LLC | Bridgman | MI | 20–99 | ◐ LIKELY ACTIVE |
| IHIndustrial Handling Services INC | Alplaus | NY | — | ◐ LIKELY ACTIVE |
| IHIndustrial Heat Treat LLC | Salt Lake City | UT | — | ◐ LIKELY ACTIVE |
| IMIndustrial Maintenance and Welding | Chicago | IL | 100–499 | ◐ LIKELY ACTIVE |
| IMIndustrial Manufacturing Services | Lancaster | SC | 20–99 | ◐ LIKELY ACTIVE |
| IMIndustrial Metal Enterprises LLC | Blackfoot | ID | 20–99 | ◐ LIKELY ACTIVE |
| IPIndustrial Panel Solutions, Inc. | Omaha | NE | 1–19 | ◐ LIKELY ACTIVE |
| IPIndustrial Products | Coon Rapids | MN | 20–99 | ◐ LIKELY ACTIVE |
| ISIndustrial Stripping Services LLC | Grand Rapids | MI | 20–99 | ◐ LIKELY ACTIVE |
| ITIndustrial Technologies Group ITG Bartell | Rome | NY | 100–499 | ◐ LIKELY ACTIVE |
| ITIndustrial Technologies Group ITG CA Design Exeter | Dover | NH | 100–499 | ◐ LIKELY ACTIVE |
| ITIndustrial Technologies Group ITG CA Design Raleigh | Raleigh | NC | 20–99 | ◐ LIKELY ACTIVE |
| ITIndustrial Technologies Group ITG Field Controls | Kinston | NC | 100–499 | ◐ LIKELY ACTIVE |
| ITIndustrial Technologies Group ITG Precision Engineering | Uxbridge | MA | 20–99 | ◐ LIKELY ACTIVE |
| ITIndustrial Technologies Group ITG Versatile Mold and Design | Rutledge | GA | 20–99 | ◐ LIKELY ACTIVE |
| ITIndustrial Technologies Group ITG WakefieldNashua | Nashua | NH | 100–499 | ◐ LIKELY ACTIVE |
| IIndy | Indianapolis | IN | 1–19 | ◐ LIKELY ACTIVE |
| IIIN-FAB Inc. | Bedford | IN | 20–99 | ◐ LIKELY ACTIVE |
| IDInfastech, Decorah MFG (IND, EF) Emhart Tecknologies LLC | Decorah | IA | 100–499 | ◐ LIKELY ACTIVE |
| IDInfinity Drain LTD | Amityville | NY | 100–499 | ◐ LIKELY ACTIVE |
| IFInfinity Finishing Services, Inc. | Fort Worth | TX | 1–19 | ◐ LIKELY ACTIVE |
| INInland NW Metallurgical | Spokane Valley | WA | 1–19 | ◐ LIKELY ACTIVE |
| ITInlet Tools, INC | Conneautville | PA | — | ◐ LIKELY ACTIVE |
| IWInnisfallen Works | Springfield | OH | 20–99 | ◐ LIKELY ACTIVE |
| ILInnova LLC | Grapevine | TX | — | ◐ LIKELY ACTIVE |
| IFInnovation First Manufacturing, Inc. | Greenville | TX | 20–99 | ◐ LIKELY ACTIVE |
| IMInnovations Manufacturing INC | Redding | CA | — | ◐ LIKELY ACTIVE |
| IAInnovative Aspects LLC | Houston | TX | — | ▲ REPORTED CLOSED |
| IEInnovative Engineered Solutions | Wilmington | OH | 20–99 | ◐ LIKELY ACTIVE |
| IMInnovative Mechanical Solutions LLC- IMECH | Houston | TX | 20–99 | ◐ LIKELY ACTIVE |
| IDInrock Drilling Systems | Houston | TX | 20–99 | ◐ LIKELY ACTIVE |
| ICInsingerMachine Company | Philadelphia | PA | 20–99 | ◐ LIKELY ACTIVE |
| IWInsteel Wire Products Home offices | Mount Airy | NC | 100–499 | ◐ LIKELY ACTIVE |
| IWInsteel Wire Products KYW | Hickman | KY | 20–99 | ◐ LIKELY ACTIVE |
| IWInsteel Wire Products NCW | Mount Airy | NC | 100–499 | ◐ LIKELY ACTIVE |
| IWInsteel Wire Products OHW | Upper Sandusky | OH | 20–99 | ◐ LIKELY ACTIVE |
| IWInsteel Wire Products TXS | Houston | TX | 20–99 | ◐ LIKELY ACTIVE |
| IEInstitutional Equipment INC | Bolingbrook | IL | — | ◐ LIKELY ACTIVE |
| INInteger N2 Surface Technologies | Woonsocket | MA | 20–99 | ◐ LIKELY ACTIVE |
| IQInteger, QKP | Quakertown | PA | 100–499 | ◐ LIKELY ACTIVE |
| IFIntegral Fabrication & Engineering, LLC | Orlando | FL | — | ◐ LIKELY ACTIVE |
| IMIntegrated Machining CO | Albuquerque | NM | — | ◐ LIKELY ACTIVE |
| IMIntegrated Machining Solutions INC | Norwalk | CA | — | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Additive Technology Center | West Chester | OH | 100–499 | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Asheville CMC | Asheville | NC | 100–499 | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Asheville Rotating Parts | Asheville | NC | 100–499 | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Auburn AL | Auburn | AL | 100–499 | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Batesville MS | Batesville | MS | 100–499 | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Dayton OH Unison | Dayton | OH | 100–499 | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing DCCDayton | Dayton | OH | 20–99 | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Evendale OH | Cincinnati | OH | 500+ | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Greenville SC | Piedmont | SC | 100–499 | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Hooksett NH | Hooksett | NH | 500+ | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Lynn MA | Lynn | MA | 500+ | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Madisonville Ky | Madisonville | KY | 100–499 | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Muskegon MI | Norton Shores Muskegon | MI | 500+ | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Rutland VT | North Clarendon | VT | 500+ | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Terre Haute IN | Terre Haute | IN | 100–499 | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing West Jefferson NC | West Jefferson | NC | 100–499 | ◐ LIKELY ACTIVE |
| IMIntegrated Manufacturing Wilmington NC | Castle Hayne | NC | 500+ | ◐ 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 |
| IIIntegration INC | Albuquerque | NM | — | ◐ LIKELY ACTIVE |
| IIIntegricoat, INC. | Spring Lake | MI | — | ◐ LIKELY ACTIVE |
| IEIntegrity Engineering Holding, Inc | Ramsey | MN | 20–99 | ◐ LIKELY ACTIVE |
| IMIntegrity Machining, INC | Augusta | IL | — | ◐ LIKELY ACTIVE |
| IMIntegrity Manufacturing CORP | Dayton | OH | — | ◐ LIKELY ACTIVE |
| ITIntegrity Tool INC | Batesville | IN | — | ◐ LIKELY ACTIVE |
| IVIntellectual Ventures Property Holdings LLC | Bellevue | WA | — | ◐ LIKELY ACTIVE |
| ISIntellifab Solutions LLC | Atlanta | GA | — | ◐ LIKELY ACTIVE |
| ICIntelligent Composites LLC | Milwaukee | WI | — | ◐ LIKELY ACTIVE |
| IGIntellisteel Group LLC | Groveland | FL | 1–19 | ◐ LIKELY ACTIVE |
| ICInter-city Contracting, INC | Smithfield | RI | — | ◐ LIKELY ACTIVE |
| IMInter-city Manufacturing, INC. | Seaside | CA | — | ◐ LIKELY ACTIVE |
| IMInterconnection Marketing ,inc. | Canoga Park | CA | — | ◐ LIKELY ACTIVE |
International Computer Appliances Corporation | Minneapolis | MN | 100–499 | ◐ LIKELY ACTIVE |
| IQInternational Quality Advantage LLC | Windsor Mill | MD | — | ◐ LIKELY ACTIVE |
International Tool and Manufacturing, INC | Fairfield | NJ | — | ◐ LIKELY ACTIVE |
| ICInterplanetary Concepts, LLC | New Smyrna Beach | FL | — | ◐ LIKELY ACTIVE |
| ICIntra Corporation (1/1/2025-6/30/2025) | Westland | MI | 100–499 | ◐ LIKELY ACTIVE |
| IBIonbond - Beachwood | Beachwood | OH | 20–99 | ◐ LIKELY ACTIVE |
| ICIonbond - Chicago | West Chicago | IL | 20–99 | ◐ LIKELY ACTIVE |
| IDIonbond - Duncan | Duncan | SC | 20–99 | ◐ LIKELY ACTIVE |
| IBIon bond - Greensboro | Greensboro | NC | 20–99 | ◐ LIKELY ACTIVE |
| IBIon bond - Madison Heights | Madison Hgts | MI | 20–99 | ◐ LIKELY ACTIVE |
| IBIon bond - Rockaway | Rockaway | NJ | 20–99 | ◐ LIKELY ACTIVE |
| ISIonbond - St.Paul | Vadnais Heights | MN | 1–19 | ◐ LIKELY ACTIVE |
| IEIowa Engineered Procsses | Independence | IA | 20–99 | ◐ LIKELY ACTIVE |
| IGIPS Group, Inc Headquarters | San Diego | CA | 100–499 | ◐ LIKELY ACTIVE |
| IDir Distributers D. B. A. The Metal Shop | Dunnellon | FL | 20–99 | ◐ LIKELY ACTIVE |