| ITIndustrial Tank & Containment INC | Brookfield | OH | — | ◐ LIKELY ACTIVE |
| ITIndustrial Technologies Group ITG Bartell | Rome | NY | 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 |
| IFInfrastructure Fabrication LLC | Bath | PA | — | ◐ 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 |
| 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 West Jefferson NC | West Jefferson | NC | 100–499 | ◐ 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 Tank Service, LLC | Henderson | KY | 1–19 | ◐ 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 |
| ICInter-city Contracting, INC | Smithfield | RI | — | ◐ LIKELY ACTIVE |
| IMInter-city Manufacturing, INC. | Seaside | CA | — | ◐ LIKELY ACTIVE |
| IMInterconnection Marketing ,inc. | Canoga Park | CA | — | ◐ LIKELY ACTIVE |
| IMInterior Mobile Welding & Services INC | Fairbanks | AK | — | ◐ LIKELY ACTIVE |
International Computer Appliances Corporation | Minneapolis | MN | 100–499 | ◐ LIKELY ACTIVE |
| IDInternational Destination Trading LLC | Fort Lauderdale | FL | — | ◐ 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 |