| Ising Ltd | Administrative & support | 2019 |
| Island Investments Ltd | Wholesale & retail | 2019 |
| Islero Fitness Ltd | Manufacturing | 2016 |
| Ismael Khan Ltd | Health & social care | 2021 |
| Isoc Investments Ltd | Real estate | 2020 |
| Isochron Systems Ltd | Professional & scientific | 2026 |
| Isparky Electrical Services Limited | Construction | 2010 |
| Issac.Web Ltd | Information & communication | 2019 |
| Isse & Kumar Ltd | Wholesale & retail | 2021 |
| Issimaila Transport Company 1401 Ltd | Transport & logistics | 2025 |
| Ista London Limited | Construction | 2024 |
| Istighraq Ltd | Wholesale & retail | 2025 |
| IT Consol Ltd | Information & communication | 2018 |
| IT Ehub Limited | Information & communication | 2017 |
| IT Fast Limited | Wholesale & retail | 2020 |
| IT Global Consulting Ltd | Information & communication | 2022 |
| IT Journeys Ltd | Transport & logistics | 2024 |
| IT Planet Ltd | Wholesale & retail | 2023 |
| IT Umbrella Security Limited | Information & communication | 2010 |
| IT Work Solutions Ltd. | Information & communication | 2014 |
| It's a Biscuit Ltd | Manufacturing | 2020 |
| It's Your Hosting Limited | Information & communication | 2024 |
| It-Servtech Limited | Information & communication | 2019 |
| IT4CORP Ltd | Wholesale & retail | 2014 |
| Italian Roots Restaurant Limited | Hospitality | 2015 |
| Italian's Crepes Concept Ltd | Transport & logistics | 2025 |
| Itech Property Ltd | Real estate | 2018 |
| Itel (UK) Limited | Information & communication | 2012 |
| Item Emporium Ltd | Other services | 2025 |
| Itoa Limited | Construction | 2008 |
| Itoa Trading Ltd | Wholesale & retail | 2022 |
| Itsaga Ltd | Information & communication | 2017 |
| Itts Ltd | Wholesale & retail | 2017 |
| Ituraa Ltd | Hospitality | 2024 |
| ITZ Investments Ltd | Financial services | 2024 |
| Itzbuzziness Ltd | Wholesale & retail | 2023 |
| Itznet Ltd | Transport & logistics | 2018 |
| Iulian Constantin Ltd | Transport & logistics | 2020 |
| Ivanhoe Investments Ltd | Real estate | 2020 |
| Ivani Limited | Wholesale & retail | 2021 |
| Ivanovi Comers Ltd | Other services | 2018 |
| Ivas Haulage Ltd | Transport & logistics | 2019 |
| Iverna Care Limited | Health & social care | 2018 |
| Iverna South East Limited | Real estate | 2018 |
| Ivmar Ltd | Construction | 2014 |
| Ivolt Ltd | Wholesale & retail | 2011 |
| IVY Content Limited | Professional & scientific | 2025 |
| IVY Crown Gardening Limited | Administrative & support | 2022 |
| IVY Pharma Limited | Wholesale & retail | 2024 |
| IVY Transport Services Ltd | Transport & logistics | 2025 |
| Iwanta Ltd | Information & communication | 2025 |
| Iwona Limited | Health & social care | 2015 |
| IX - V: the Nine to Five Ltd | Manufacturing | 2025 |
| IYA Properties (Stoke RD) Limited | Real estate | 2021 |
| IYA Properties Limited | Financial services | 2021 |
| Iyom Property Ltd | Real estate | 2024 |
| Izivor Ltd | Wholesale & retail | 2026 |
| J & J Building Group Ltd | Construction | 2025 |
| J & J Construct Ltd | Construction | 2020 |
| J & J Driveways & Landscaping Ltd | Administrative & support | 2025 |
| J & K Properties Investment UK Limited | Real estate | 2025 |
| J & S Basra Limited | Households | 2019 |
| J a G Builders Ltd | Construction | 2007 |
| J a Horizons Ltd | Households | 2026 |
| J B Associates (Occupational Health) Ltd | Administrative & support | 2008 |
| J Banger Limited | Construction | 2011 |
| J C Homes Construction Limited | Construction | 2020 |
| J C Hotels Ltd | Real estate | 2024 |
| J H J Haulage Ltd | Water & waste | 2015 |
| J Haulage Services Ltd | Transport & logistics | 2023 |
| J J Properties & Investment Ltd | Real estate | 2025 |
| J K Estates (GB) Limited | Real estate | 2013 |
| J M Carpentry & Sons Ltd | Construction | 2026 |
| J M G Constructions Ltd | Construction | 2014 |
| J M Ventures Limited | Professional & scientific | 2012 |
| J Nationwide Property Ltd | Real estate | 2024 |
| J S Bishop and Company Ltd | Extraterritorial | 2016 |
| J S Furniture Limited | Wholesale & retail | 2025 |
| J S Gill Transport Limited | Construction | 2015 |
| J S Malhi Limited | Transport & logistics | 2014 |
| J S Roofing London Ltd | Construction | 2024 |
| J Scott Express Asphalt Limited | Construction | 2025 |
| J Seehra Property Holdings Ltd | Real estate | 2019 |
| J Tanner Holdings Ltd | Real estate | 2025 |
| J Thanan Properties Ltd | Real estate | 2021 |
| J V Design & Build Ltd | Construction | 2024 |
| J&C Trading UK PVT. Limited | Hospitality | 2025 |
| J&Dc Transport Limited | Transport & logistics | 2018 |
| J&F Decor Ltd | Construction | 2025 |
| J&G Courier Ltd | Transport & logistics | 2019 |
| J&G Sprinkler Protection Ltd | Construction | 2025 |
| J&J Capital Holdings Ltd | Real estate | 2019 |
| J&J PIP Ltd | Other services | 2024 |
| J&K Pro Services Ltd | Construction | 2024 |
| J&K Sandhu Ltd | Real estate | 2020 |
| J&M Construction Group Limited | Construction | 2023 |
| J&M Development London Ltd | Construction | 2026 |
| J&P Oral Health Limited | Health & social care | 2024 |
| J&S Global Holdings Ltd | Wholesale & retail | 2025 |
| J&S Property Ventures Limited | Real estate | 2024 |