| Inverse Investments Limited | Wholesale & retail | 2019 |
| INVEST8 Group Ltd | Financial services | 2025 |
| Invest@Um Ltd | Hospitality | 2025 |
| Investa Capital Group Holdings Ltd | Financial services | 2022 |
| Investment in Vision Ltd | Transport & logistics | 2019 |
| Investments RS Ltd | Real estate | 2024 |
| Invicta Education Consulting Ltd | Education | 2023 |
| Invicta Group Midlands Ltd | Transport & logistics | 2022 |
| Invicta Sign Solutions Ltd | Construction | 2019 |
| Invisible Industries Limited | Information & communication | 2020 |
| Invision Photo Ltd | Professional & scientific | 2021 |
| Invotech (UK) Ltd | Administrative & support | 1999 |
| ION64 Trans Limited | Transport & logistics | 2016 |
| IP Networks Ltd | Information & communication | 2017 |
| IP Protection Limited | Professional & scientific | 2009 |
| Iprosports Limited | Wholesale & retail | 2013 |
| IPW Limited | Professional & scientific | 2005 |
| IQ Strength Ltd | Information & communication | 2021 |
| Iqra Foods Limited | Wholesale & retail | 2021 |
| Iris Residential Care Limited | Health & social care | 2018 |
| Iron Gate Property Development Limited | Construction | 2025 |
| Ironstone Inns Ltd | Hospitality | 2025 |
| Irpen (UK) Limited | Wholesale & retail | 1987 |
| Isaac Tyres Ltd | Wholesale & retail | 2019 |
| Isaac's Home Improvements Ltd | Real estate | 2025 |
| Isakala Holdings Ltd | Financial services | 2021 |
| ISB Travel Ltd | Administrative & support | 2018 |
| Iser Limited | Manufacturing | 2017 |
| Isham Education and Community Ltd | Professional & scientific | 2017 |
| Ishke Brands Ltd | Wholesale & retail | 2019 |
| Ishkirat Transport Ltd | Transport & logistics | 2024 |
| Ishtiaqs Medicare Limited | Health & social care | 2022 |
| Iside Services Limited | Wholesale & retail | 2003 |
| ISJ Estate Group Ltd | Real estate | 2025 |
| Islande Contracts Ltd | Manufacturing | 2010 |
| Ismay Holdings Ltd | Financial services | 2023 |
| Isme Homes Ltd | Extraterritorial | 2013 |
| Isme Property Limited | Real estate | 2013 |
| Isnan Ltd | Construction | 2025 |
| ISO Wright Consultancy Ltd | Professional & scientific | 2024 |
| Isonomy Advisory Limited | Professional & scientific | 2020 |
| Isonomy Group Limited | Financial services | 2021 |
| Isonomy Marketplace Limited | Professional & scientific | 2024 |
| Isonomy Property Group Limited | Real estate | 2024 |
| Ispam Consulting Ltd | Professional & scientific | 2015 |
| Isquared Consultants Ltd | Hospitality | 2026 |
| ISS Flooring Limited | Construction | 2016 |
| ISS7 Ltd. | Wholesale & retail | 2019 |
| Istigatha Limited | Education | 2019 |
| Istrategy Transport Ltd | Transport & logistics | 2023 |
| Isustainable Ltd | Information & communication | 2022 |
| IT Mobility Ltd | Information & communication | 2023 |
| IT Tech Buyer Ltd | Wholesale & retail | 2018 |
| Itaas Solutions Ltd | Information & communication | 2019 |
| Itah Consultants Ltd | Professional & scientific | 2021 |
| Itec Recycle Ltd | Information & communication | 2021 |
| Itech Repair and Exchange Ltd | Wholesale & retail | 2023 |
| Itgen Solutions UK Ltd | Information & communication | 2025 |
| Itidanaha Properties Ltd. | Real estate | 2018 |
| ITK Haulage Limited | Transport & logistics | 2021 |
| ITS Easy AS 123 Ltd | Professional & scientific | 2019 |
| ITS Residential Care Consultancy Ltd | Health & social care | 2026 |
| Iulian Limited | Administrative & support | 2018 |
| Ivor Parnham Building Services Limited | Construction | 2013 |
| Ivory & Stone Limited | Construction | 2026 |
| Ivory Capital Ltd | Real estate | 2026 |
| Ivory Sufra Ltd | Hospitality | 2025 |
| IVY House Children’S Care Home Limited | Health & social care | 2026 |
| Iwellness Ltd | Wholesale & retail | 2021 |
| Iwok Food Solutions Ltd | Hospitality | 2010 |
| IWS M&E Services Limited | Extraterritorial | 2001 |
| IWS Pipeline Services Limited | Extraterritorial | 2003 |
| IY Earnings Limited | Construction | 2025 |
| Izzah Trading Ltd | Hospitality | 2021 |
| J & E Sedgwick & Company (2018) Limited | Manufacturing | 2018 |
| J & J Engineering (Walsall) Limited | Administrative & support | 1982 |
| J & K Sahota Ltd | Wholesale & retail | 2025 |
| J & K SK Limited | Wholesale & retail | 2015 |
| J & S Lunt Motor Services Limited | Wholesale & retail | 2011 |
| J Alton Property Ltd | Real estate | 2025 |
| J and G Driver Solutions Ltd | Administrative & support | 2021 |
| J and G'S Estates Limited | Real estate | 2020 |
| J and R (Public House) Limited | Transport & logistics | 2025 |
| J and Y Transport Ltd | Transport & logistics | 2023 |
| J B Goodman & Sons Limited | Construction | 2005 |
| J B Property Group Ltd | Real estate | 2019 |
| J Beauty Company Limited | Administrative & support | 2016 |
| J C Marklew Ltd | Construction | 2018 |
| J C Payne (UK) Limited | Manufacturing | 2009 |
| J D Karate Schools Limited | Arts & recreation | 2024 |
| J D L Decorators Limited | Construction | 2019 |
| J D Legacy Ltd | Hospitality | 2025 |
| J D Travel Ltd | Transport & logistics | 2015 |
| J Degg Inc Ltd | Administrative & support | 2022 |
| J G Zinc Alloys Ltd | Administrative & support | 2026 |
| J Harper & Sons (Welding Fabrications) Limited | Manufacturing | 1962 |
| J M G Roofing Ltd | Construction | 2010 |
| J O Publishing Ltd | Information & communication | 2014 |
| J P Tiling Contractors Limited | Construction | 2009 |
| J Potton Consulting Ltd | Information & communication | 2018 |