| Indisoft Business Solutions Limited | Information & communication | 1994 |
| Inductaflex Limited | Manufacturing | 2014 |
| Industrial Bearings Limited | Extraterritorial | 1964 |
| Industrial Electric Gates and Bollards Limited | Administrative & support | 2025 |
| Industrial Installations DA Ltd | Manufacturing | 2024 |
| Industrial Physics UK Holding Company Limited | Financial services | 2026 |
| Industrial Supplies Direct (Telford) Limited | Wholesale & retail | 2003 |
| Industrilas U.K. Limited | Manufacturing | 2017 |
| Industry Signage Ltd | Professional & scientific | 2022 |
| Infinite Parcel Solutions Ltd | Transport & logistics | 2021 |
| Infinite QI Limited | Administrative & support | 2022 |
| Infinity Energy Holdings Ltd | Financial services | 2025 |
| Infinity Project Properties Limited | Real estate | 2024 |
| Information Technology Clear Limited | Wholesale & retail | 2001 |
| Infusion Print Ltd | Manufacturing | 2025 |
| Ingenium.Eng Limited | Professional & scientific | 2010 |
| Ingress Virtual Services Ltd | Information & communication | 2024 |
| Inicio Change Ltd | Real estate | 2024 |
| Initro Ltd | Wholesale & retail | 2019 |
| Innovare Ltd | Professional & scientific | 2021 |
| Innovation Bars Ltd | Real estate | 2018 |
| Innovation Cubed Ltd | Professional & scientific | 2012 |
| Innovative Franchise Ltd | Administrative & support | 2015 |
| Innvotel Limited | Extraterritorial | 1982 |
| Inscription Limited | Administrative & support | 2020 |
| Insight Imaging Solutions Ltd | Health & social care | 2024 |
| Insito Ltd | Professional & scientific | 2021 |
| Inspeed Logistic Ltd | Transport & logistics | 2023 |
| Inspire & Bless Limited | Professional & scientific | 2021 |
| Inspired by the Best Ltd | Manufacturing | 2023 |
| Inspired Fightwear Limited | Wholesale & retail | 2022 |
| Inspirions Ltd | Other services | 2019 |
| Instafence Ltd | Construction | 2026 |
| Instaloft Ltd | Construction | 2014 |
| Instaspark Ltd | Construction | 2015 |
| Intatrim Ltd | Other services | 2016 |
| INTEGR4 Ltd | Administrative & support | 2025 |
| Integra Homes Limited | Construction | 1999 |
| Integratile Limited | Construction | 2019 |
| Integrino Ltd | Other services | 2024 |
| Inteler Ltd | Other services | 2019 |
| Intelligent Returns Limited | Financial services | 2016 |
| Interactive Consultants Limited | Professional & scientific | 2022 |
| Interface NRM Employees Trustee Ltd | Financial services | 2020 |
| Interface NRM Limited | Agriculture & fishing | 2002 |
| Interfix Roofing Services Ltd | Construction | 2018 |
| Intergalactic Loft Insulation Ltd | Construction | 2025 |
| Internal Fitout Solutions Ltd | Construction | 2025 |
| International Cookware Designs Ltd | Wholesale & retail | 1999 |
| International Schools Consulting Limited | Education | 2020 |
| International Solar Cleaning Academy Ltd | Education | 2022 |
| International Talent Group Limited | Arts & recreation | 2016 |
| Interspiro Limited | Administrative & support | 1974 |
| Intimate Properties Limited | Real estate | 2015 |
| Intranova Solutions Ltd | Information & communication | 2025 |
| Intrinsic Paper Products Limited | Manufacturing | 2019 |
| Intrinsic Paper Straws Limited | Manufacturing | 2019 |
| Introvision Designs Limited | Information & communication | 2020 |
| Invensys Group Holdings Limited | Financial services | 1952 |
| Invensys Group Limited | Professional & scientific | 2004 |
| Invensys Holdings Limited | Extraterritorial | 1991 |
| Invensys International Holdings Limited | Professional & scientific | 1898 |
| Invensys Limited | Financial services | 1920 |
| Invensys Overseas Limited | Professional & scientific | 1966 |
| Invensys Secretaries Limited | Professional & scientific | 1972 |
| Invensys Twenty-One Limited | Professional & scientific | 1951 |
| Investing in Wellbeing Ltd | Health & social care | 2022 |
| Investments U.K. Ltd | Real estate | 2016 |
| Investments UK Limited | Real estate | 2002 |
| Invictus Estates Ltd | Administrative & support | 2023 |
| Invincible Garage Limited | Wholesale & retail | 2026 |
| Inviroflow Limited | Manufacturing | 2021 |
| Inxecs Management Solutions Ltd | Real estate | 2025 |
| Iperiks Ltd | Other services | 2018 |
| Ipkg Limited | Information & communication | 2026 |
| IQ Holdings Limited | Real estate | 2022 |
| Irenetech Limited | Wholesale & retail | 2025 |
| Irholn International Limited | Health & social care | 2015 |
| Iridum Spa Limited | Other services | 2007 |
| Irigreen Limited | Transport & logistics | 2022 |
| Irina Bassett Photography Ltd | Information & communication | 2021 |
| Irine Jewellery Company Ltd | Wholesale & retail | 2022 |
| Iron Forest Limited | Manufacturing | 2021 |
| Iron Giant Appliances Ltd | Wholesale & retail | 2024 |
| Iron Gorge Camping Limited | Hospitality | 2014 |
| Iron Horse HR Ltd | Administrative & support | 2019 |
| Iron Sky Investments Ltd | Hospitality | 2024 |
| Ironbirch Properties Limited | Real estate | 2016 |
| Ironbridge Antiques, Arts & Crafts Centre Ltd | Wholesale & retail | 2011 |
| Ironbridge Developments Ltd | Manufacturing | 2023 |
| Ironbridge Digital Studio Ltd | Information & communication | 2026 |
| Ironbridge Financial Services Ltd | Extraterritorial | 2020 |
| Ironbridge Fine Arts and Framing Limited | Manufacturing | 2006 |
| Ironbridge Fish & Chips Ltd | Hospitality | 2023 |
| Ironbridge Gastroenterology and Medical Services Ltd | Health & social care | 2020 |
| Ironbridge Interiors Limited | Manufacturing | 2010 |
| Ironbridge NDT Limited | Professional & scientific | 2014 |
| Ironbridge Property Ltd | Real estate | 2024 |
| Ironbridge Property Plus Ltd | Real estate | 2025 |
| Ironbridge Windows & Doors Limited | Manufacturing | 2024 |