| Invest Services SEO Ltd | Other services | 2024 |
| Invest Solution PC | | 2023 |
| Investa Properties Limited | Households | 2018 |
| Investably Investors Limited | Other services | 2019 |
| Investdiff Ltd | Real estate | 2021 |
| Investeam Consulting Ltd | Financial services | 2023 |
| Investech AI Ltd | Professional & scientific | 2022 |
| Investent Ltd | Financial services | 2021 |
| Investent Property Maintenance Ltd | Construction | 2025 |
| Investis Securities Limited | Financial services | 2017 |
| Investitec Ltd | Financial services | 2025 |
| Investment Advisory Services Ltd | Information & communication | 2025 |
| Investment Construction Limited | Construction | 2011 |
| Investor Nexus Limited | Administrative & support | 2024 |
| Investoz Ltd | Administrative & support | 2018 |
| Investra Ltd | Financial services | 2021 |
| Invicta Realty Ltd | Real estate | 2024 |
| Invictus Care Ltd | Health & social care | 2023 |
| Invictus Holdings Southwest Limited | Extraterritorial | 2014 |
| Invictus Holdings USA Limited | Information & communication | 2025 |
| Invictus Investments Group Ltd | Real estate | 2018 |
| Invictus Investments Holding Ltd | Mining & quarrying | 2021 |
| Invictus Property Management Ltd | Real estate | 2025 |
| Invincible Cultural Media Ltd | Wholesale & retail | 2025 |
| Invincible Media Limited | Information & communication | 2018 |
| Inviro Choice Limited | Manufacturing | 2011 |
| Inviseen Ltd | Professional & scientific | 2026 |
| Invisible Software 2.0 Ltd | Information & communication | 2014 |
| Invision TV Ltd | Information & communication | 2008 |
| Invista Capital Advisers Ltd | Professional & scientific | 2014 |
| Invito Ltd | Professional & scientific | 2024 |
| Invoicia Ltd | Professional & scientific | 2021 |
| Involegal Limited | Extraterritorial | 2000 |
| Invyte Technologies Limited | Information & communication | 2023 |
| Inwood Fixings Ltd | Wholesale & retail | 2024 |
| Inza-Agency Ltd | Information & communication | 2025 |
| IO Build & Design Ltd | Construction | 2026 |
| IO Build & Design Services Ltd | Construction | 2026 |
| Ioan Rhys Davies CYF | Professional & scientific | 2025 |
| Iolite Group Ltd | Real estate | 2020 |
| Iolo Energy Limited | Construction | 2020 |
| Iolo Holdings Limited | Financial services | 2025 |
| Iolo Nominee Limited | Financial services | 2025 |
| Iolo Studios Limited | Information & communication | 2024 |
| ION Builders Ltd | Construction | 2019 |
| ION Distribution Ltd | Manufacturing | 2018 |
| ION Marin Auto Ltd | Wholesale & retail | 2020 |
| Ion.Dav Ltd | Transport & logistics | 2018 |
| ION@ Limited | Arts & recreation | 2022 |
| Ionie's Care Ltd | Health & social care | 2018 |
| Ionoa Ltd | Information & communication | 2014 |
| IOS Bits Ltd | Administrative & support | 2011 |
| IOS Care Limited | Real estate | 2020 |
| IOS Recruitment and Training Services Ltd | Administrative & support | 2009 |
| Iosa Ltd | Professional & scientific | 2020 |
| Iosiv Smart Choice Limited | Manufacturing | 2025 |
| IOT Automotive News Ltd | Administrative & support | 2016 |
| IOT Comm Ltd | Information & communication | 2019 |
| Iott Innovations Ltd | Manufacturing | 2017 |
| Iowekr Ltd | Manufacturing | 2026 |
| IP Fitness Limited | Construction | 2019 |
| IP Industrial Services Limited | Construction | 2024 |
| IPA Homes Ltd | Real estate | 2024 |
| Ipaif Unlimited PC | | 2020 |
| Ipalmdirect Ltd | Wholesale & retail | 2017 |
| Ipass (GU1) Ltd | Information & communication | 2022 |
| Ipass (SW1) Ltd | Information & communication | 2022 |
| IPE Odelia Limited | Wholesale & retail | 2025 |
| Ipec World Cargo Ltd | Transport & logistics | 2020 |
| Ipek Yolu Ltd | Wholesale & retail | 2019 |
| IPG Homes Limited | Real estate | 2020 |
| IPG Radiology Limited | Health & social care | 2009 |
| Ipil Limited | Wholesale & retail | 2026 |
| Iplumb Cardiff Ltd | Construction | 2025 |
| Ipoint Technology UK Limited | Information & communication | 2017 |
| Ipro Link UK Limited | Hospitality | 2017 |
| Iproche Ltd | Wholesale & retail | 2020 |
| Iprod Holding Ltd. | Administrative & support | 2016 |
| Iproperty Group Limited | Real estate | 2022 |
| Iprotect Ltd | Administrative & support | 2025 |
| Ipso Consulting Ltd | Information & communication | 2025 |
| Ipsos Prime Ltd | Professional & scientific | 2018 |
| Ipspine Inc Limited | Construction | 2015 |
| Ipswich Holdings Limited | Real estate | 1975 |
| Ipswich Road Estates Limited | Real estate | 2012 |
| Ipswich Ship Repair Yard Limited | | 1981 |
| Iptrix Agency Ltd | Information & communication | 2024 |
| Ipynerk Ltd | Education | 2025 |
| IQ Digital Solutions Limited | Information & communication | 2019 |
| IQ Sun Ltd. | Administrative & support | 2018 |
| Iqbal Biland Ltd | Wholesale & retail | 2025 |
| Iqbal Mart Ltd | Wholesale & retail | 2026 |
| Iqbal Motors Repairs and Sales Ltd | Wholesale & retail | 2024 |
| IQC Ltd | Professional & scientific | 2017 |
| Iqdev Limited | Information & communication | 2018 |
| IQE (Europe) Limited | Manufacturing | 1987 |
| IQE PLC | Professional & scientific | 1999 |
| IQE Silicon Compounds Limited | Manufacturing | 2000 |
| Iqra Capital Limited | Real estate | 2010 |
| Iqra Collection Limited | Extraterritorial | 2026 |