| Investment Wise Limited | Wholesale & retail | 2016 |
| Investotech Ltd | Financial services | 2025 |
| Invicta Aero Club Limited | Arts & recreation | 2022 |
| Invicta Audio Visual Limited | Administrative & support | 2016 |
| Invicta Caravan Services Ltd | Wholesale & retail | 2018 |
| Invicta Carpentry Limited | Construction | 2019 |
| Invicta Cricket Coaching (Schools) Limited | Arts & recreation | 2020 |
| Invicta Cricket Coaching (Sevenoaks) Limited | Arts & recreation | 2020 |
| Invicta Dynamos Limited | Arts & recreation | 2000 |
| Invicta Electrical & Building Services Limited | Construction | 2016 |
| Invicta Financial Solutions Ltd | Financial services | 2015 |
| Invicta Fire & Security Systems Limited | | 1986 |
| Invicta Flair Limited | Other services | 2015 |
| Invicta Flooring Limited | Construction | 2026 |
| Invicta Fruit Services Limited | Administrative & support | 2013 |
| Invicta Living Solutions Limited | Professional & scientific | 2015 |
| Invicta P S I Ltd | Administrative & support | 2023 |
| Invicta Pest Solutions Ltd | Administrative & support | 2026 |
| Invicta Pharma Limited | Wholesale & retail | 2012 |
| Invicta Professional Engineering Services Ltd | Professional & scientific | 2023 |
| Invicta Project Solutions Ltd | Construction | 2022 |
| Invicta Trucking Limited | Transport & logistics | 2019 |
| Invicta Valves Limited | Wholesale & retail | 1982 |
| Invictus Worldwide Ltd | Administrative & support | 2025 |
| Inviqa UK Limited | Other services | 2007 |
| Invisible Movie Limited | Information & communication | 2025 |
| Involve Kent Limited | Health & social care | 1997 |
| Ioeb Limited | Construction | 2020 |
| Iola Enterprise Ltd | Wholesale & retail | 2023 |
| Iosub Transport 2015 Limited | Transport & logistics | 2015 |
| IP Food Technical Services Ltd | Hospitality | 2016 |
| IPE Management Ltd | Education | 2020 |
| IPG Global Limited | Other services | 2026 |
| IPM Enterprises Ltd | Energy | 2017 |
| Ireland and Co Lettings Ltd | Households | 2025 |
| Ireland Plumbing Ltd | Construction | 2015 |
| Irispro Ltd | Wholesale & retail | 2024 |
| IRL Limited | Administrative & support | 2024 |
| Irma's Beauty Ltd | Other services | 2019 |
| Iron Hearse Limited | Other services | 2019 |
| Iron Processing Ltd | Manufacturing | 2025 |
| Ironmistress Limited | Information & communication | 2019 |
| Ironridge Ltd | Construction | 2024 |
| IRS Facilities Ltd | Real estate | 2018 |
| Irvann Property Investment Limited | Real estate | 2011 |
| Irvine Creations Ltd | Extraterritorial | 2021 |
| Irwin Smith Ltd | Construction | 2006 |
| Isgt Ltd | Wholesale & retail | 2023 |
| Island HUT Cafe Ltd | Hospitality | 2015 |
| Island Management Services Ltd | Construction | 2025 |
| Isle Landscapers Limited | Administrative & support | 2014 |
| Isohelix Limited | Extraterritorial | 2012 |
| Issac Education Ltd | Education | 2023 |
| Issam Cabs Limited | Transport & logistics | 2024 |
| IT & Accounting Solutions Limited | Professional & scientific | 2004 |
| IT Rocketship Ltd | Information & communication | 2025 |
| IT Vintage Solutions Limited | Information & communication | 2015 |
| ITA Projects Limited | Construction | 2023 |
| Italiano KT Limited | Hospitality | 2026 |
| Itech Electrical Contractors Limited | Construction | 2019 |
| Itech Security & Electrical Limited | Construction | 2012 |
| Itechel Ltd | Information & communication | 2023 |
| Ithiel Consulting Limited | Wholesale & retail | 2007 |
| Itomni Ltd | Information & communication | 2014 |
| Itrellis Ltd. | Information & communication | 2014 |
| Itresource Limited | Information & communication | 2008 |
| ITS Leadership Ltd | Professional & scientific | 2007 |
| Iulian Cardos Limited | Professional & scientific | 2018 |
| Iulianatrans Ltd | Transport & logistics | 2024 |
| IVA Logistics Consultancy Ltd | Construction | 2024 |
| Ivan 2017 BG Ltd | Construction | 2018 |
| Ivaron Construction Group Limited | Construction | 2018 |
| Ivaron Group Limited | Construction | 2021 |
| Ivasta Logistic Ltd | Transport & logistics | 2022 |
| Ivdeology Holdings Ltd | Professional & scientific | 2020 |
| Ivdeology Ltd | Professional & scientific | 2018 |
| Ivdeology Ukrp Ltd | Professional & scientific | 2020 |
| Iverson Group Holdings Ltd | Financial services | 2020 |
| Iverson Tyres Limited | Extraterritorial | 1992 |
| IVS London Limited | Administrative & support | 2025 |
| IVY House Solutions Ltd | Professional & scientific | 2025 |
| IVY Mind Ltd | Education | 2024 |
| Ivydene Limited | Wholesale & retail | 1981 |
| IY Studios Limited | Arts & recreation | 2008 |
| Iyuno UK III Ltd. | Information & communication | 1999 |
| IZ Move Limited | Transport & logistics | 2025 |
| J & D Renewables Limited | Information & communication | 2017 |
| J & M Gooden Properties Ltd | Real estate | 2018 |
| J & M Roofing and Property Maintenance Ltd | Construction | 2025 |
| J & P Engineering (SE) Ltd | Professional & scientific | 2021 |
| J & S Footcare Ltd | Other services | 2003 |
| J a Worley Limited | Agriculture & fishing | 1997 |
| J B Crayford Electrical Limited | Construction | 2025 |
| J B Gate Systems Limited | Manufacturing | 2012 |
| J Clark Engineering Ltd | Wholesale & retail | 2023 |
| J Clement Ltd | Real estate | 2020 |
| J D Alloys Ltd | Wholesale & retail | 2025 |
| J D Property Estates Services Limited | Real estate | 2024 |
| J Davis Building Services Ltd | Construction | 2026 |
| J Dempson & Co Limited | Professional & scientific | 1945 |