| ISL Trans Ltd | Transport & logistics | 2015 |
| Isla Brava Hair Ltd | Wholesale & retail | 2026 |
| Islamorada Limited | Real estate | 2022 |
| Island Catering Ltd | Hospitality | 2023 |
| Island Comms Ltd | Information & communication | 2017 |
| Isle Export Consultants Ltd | Professional & scientific | 2019 |
| Islimroj Properties Ltd | Real estate | 2025 |
| Ismail Abul Ltd | Wholesale & retail | 2025 |
| Ismail CAF Ltd | Hospitality | 2025 |
| Isns Ltd | Wholesale & retail | 2012 |
| Isotec Ltd | Construction | 2020 |
| Israep Limited | Health & social care | 2023 |
| Issf Ltd | Construction | 2020 |
| ISY Contractors Ltd | Construction | 2025 |
| IT DG Consulting Limited | Information & communication | 2012 |
| IT E.&S. Limited | Information & communication | 2014 |
| IT Office Limited | Information & communication | 2019 |
| IT Renew Recycling Ltd | Wholesale & retail | 2024 |
| IT Serve Limited | Information & communication | 2017 |
| IT Systems Support Limited | Information & communication | 2023 |
| IT Tree Limited | Information & communication | 2021 |
| It's Mine Ltd | Wholesale & retail | 2024 |
| It-Pro Vision Limited | Wholesale & retail | 2021 |
| Ital Constructions Ltd | Construction | 2023 |
| Italian Express Pasta & Pizza Limited | Hospitality | 2013 |
| Italianissimo Limited | Hospitality | 2014 |
| Italnatural Wines Ltd | Wholesale & retail | 2024 |
| Itarians Solutions Ltd | Wholesale & retail | 2026 |
| ITB Solutions Limited | Professional & scientific | 2012 |
| Itcare Center UK Ltd | Wholesale & retail | 2025 |
| Itelect Solutions Ltd | Information & communication | 2005 |
| Itician AK Ltd | Wholesale & retail | 2025 |
| Itjl-Jn Kalsana Restaurant Ltd | Hospitality | 2023 |
| Itmacare Services Ltd | Administrative & support | 2022 |
| Itoc Investment & MGT Services Ltd | Real estate | 2020 |
| Itoxsys UK Ltd | Information & communication | 2023 |
| ITS Shop-Fit Ltd. | Construction | 2017 |
| Itsalldrip Limited | Wholesale & retail | 2022 |
| Itsbd Ltd | Information & communication | 2024 |
| Itsbeads Limited | Manufacturing | 2024 |
| Itspire Solutions Ltd | Information & communication | 2019 |
| ITW Solutions Ltd | Information & communication | 2009 |
| Iuga Engineering Ltd | Construction | 2020 |
| Iuga Ltd | Construction | 2023 |
| Iulian Panaguta Ltd | Manufacturing | 2024 |
| IVA and Holly Properties Ltd | Real estate | 2025 |
| Ivabeks Social Care Ltd | Health & social care | 2022 |
| Ivan Plastering Ltd | Construction | 2025 |
| Ivan's Kitchen Ltd | Wholesale & retail | 2025 |
| Ivana Franka Consulting Ltd | Information & communication | 2022 |
| IVB Construction Ltd | Construction | 2020 |
| Ives Electrical Services Ltd | Construction | 2016 |
| IVN Fire Protection Limited | Construction | 2015 |
| IVN Properties Limited | Real estate | 2025 |
| Ivory Brown Ltd | Professional & scientific | 2019 |
| IVV Construction Ltd | Construction | 2025 |
| IVY Adorn Limited | Other services | 2024 |
| IVY Loutheo 2 Ltd | Real estate | 2023 |
| IVY Loutheo Ltd | Real estate | 2021 |
| IVY Richards Group Limited | Financial services | 2021 |
| Ivydiscounts Ltd | Wholesale & retail | 2016 |
| Iwinosa Vineyard Company Ltd | Health & social care | 2023 |
| Ixinfotech Ltd | Information & communication | 2026 |
| Iyas Personal Training Ltd | Arts & recreation | 2020 |
| Iyen & Co. Executive Solutions Ltd | Professional & scientific | 2025 |
| IZ Property Holdings Ltd | Real estate | 2025 |
| IZ REP Services Limited | Professional & scientific | 2026 |
| Izee Solutions Ltd | Information & communication | 2017 |
| Izel Brands Ltd | Wholesale & retail | 2026 |
| IZU & JJ Limited | Health & social care | 2019 |
| Izzah Foods Ltd | Manufacturing | 2026 |
| J & C Lettings Ltd | Real estate | 2023 |
| J & CJ Frozen Foods (Essex) Limited | Hospitality | 2023 |
| J & E Training Consultants Limited | Education | 2001 |
| J & H Auto Assist Ltd | Wholesale & retail | 2020 |
| J & J Builders (UK) Ltd | Construction | 2015 |
| J & JO Traders Ltd | Wholesale & retail | 2016 |
| J & M Shopfront Glazing Ltd | Construction | 2022 |
| J & N Car Hire Services Limited | Administrative & support | 2015 |
| J & Y Market Ltd | Wholesale & retail | 2025 |
| J a Scott Electrical Limited | Construction | 2016 |
| J and G Maintenance Ltd | Administrative & support | 2023 |
| J and J Building and Renovating Services Limited | Construction | 2021 |
| J and J Consulting London Ltd | Education | 2024 |
| J Badshah Builders Ltd | Construction | 2024 |
| J C Floors Limited | Construction | 2017 |
| J COX Electrical Services Limited | Construction | 2019 |
| J D Estate Holdings UK Ltd | Real estate | 2024 |
| J D P Electrical Services Limited | Construction | 2007 |
| J Durrant & Family Ltd | Agriculture & fishing | 2023 |
| J E Pereira & Sons Ltd | Professional & scientific | 2024 |
| J H B Heating Ltd | Construction | 2017 |
| J H Strategy Ltd | Real estate | 2020 |
| J J Kitchen Ltd | Hospitality | 2025 |
| J K Services (Essex) Limited | Construction | 2003 |
| J Kash Holding Limited | Real estate | 2023 |
| J Kash Limited | Construction | 2015 |
| J M Harris Limited | Agriculture & fishing | 2022 |
| J Marsh Estates Ltd | Real estate | 2021 |
| J Maynard Limited | Extraterritorial | 2013 |