| Inger T Limited | Hospitality | 2018 |
| Inksp Limited | Construction | 2014 |
| Innoconnect Limited | Wholesale & retail | 2023 |
| Insecta Nova Ltd | Agriculture & fishing | 2025 |
| Inshureai Consulting Ltd | Professional & scientific | 2023 |
| Inspire Social Work Ltd | Health & social care | 2021 |
| Inspired Education London Limited | Information & communication | 2013 |
| Inspiring Community Events Ltd | Administrative & support | 2023 |
| Intact Creatives Limited | Professional & scientific | 2022 |
| Integrity Construction Services Limited | Construction | 2016 |
| Interflow Services Ltd | Other services | 2021 |
| Interiors Interiors Ltd | Construction | 2009 |
| International Medical Devices Ltd | Wholesale & retail | 2011 |
| Intofpv Ltd | Information & communication | 2024 |
| Intouch Property Investing Ltd | Real estate | 2021 |
| Intranet Solutions Limited | Wholesale & retail | 2022 |
| Intrinsic Risk Management Limited | Administrative & support | 2013 |
| Invermene House RTM Company Limited | Households | 2021 |
| Investice Ltd | Financial services | 2025 |
| Investogram at Auma Limited | Real estate | 2019 |
| Ioutsource Limited | Information & communication | 2014 |
| Iqra Holding Ltd | Transport & logistics | 2022 |
| Iravidarts Limited | Information & communication | 2022 |
| Irdm Limited | Health & social care | 2018 |
| Irie Foods Ltd | Agriculture & fishing | 2023 |
| Irina Educational Services Ltd | Education | 2025 |
| Ironwood Stables Ltd | Agriculture & fishing | 2025 |
| Irving Peiris Compliance Professional Limited | Professional & scientific | 2026 |
| Isda Mouldings Ltd | Construction | 2021 |
| Island Dental Care Limited | Health & social care | 2016 |
| Ismail Restaurants Ltd | Hospitality | 2023 |
| ISS Enterprise Ltd | Other services | 2013 |
| IT Impi Ltd | Information & communication | 2016 |
| Itec Systems Consultancy Ltd | Information & communication | 2010 |
| Itechdevices UK Ltd | Wholesale & retail | 2017 |
| Ithames Solutions Limited | Information & communication | 2013 |
| Itinken Limited | Information & communication | 2009 |
| Itta Properties Ltd | Real estate | 2023 |
| Ituland Ltd | Hospitality | 2012 |
| Ivana&Coaesthetics Limited | Other services | 2025 |
| Ivkon Fitting Limited | Transport & logistics | 2015 |
| IVY FOX Ltd | Wholesale & retail | 2025 |
| Iwise Partners Limited | Professional & scientific | 2023 |
| Iwtm-Uk Ltd | Water & waste | 2019 |
| IYI Development Limited | Construction | 2024 |
| Izzi Cars Ltd | Wholesale & retail | 2024 |
| Izzorah Cleaning and Home Care Ltd | Administrative & support | 2021 |
| J & O Property Enterprises Limited | Real estate | 2020 |
| J a P Holdings Group Limited | Financial services | 2024 |
| J L Gardening Services Ltd | Administrative & support | 2008 |
| J P & Sons Scaffolding Limited | Construction | 2011 |
| J&J Properties (South) Ltd | Real estate | 2023 |
| J&O Services Ltd | Wholesale & retail | 2015 |
| J&Q Catering Training Ltd | Other services | 2026 |
| J-Art Ltd | Wholesale & retail | 2023 |
| J.Ethan Consulting Limited | Information & communication | 2015 |
| J.Mccreddie Ltd | Wholesale & retail | 2022 |
| J2 Accounting Limited | Professional & scientific | 2018 |
| JA9 Journeys Ltd | Administrative & support | 2022 |
| Jaas Property Ltd | Real estate | 2018 |
| JAC Capital Holdings Ltd | Financial services | 2026 |
| Jack Rose (Surrey) Limited | Transport & logistics | 1959 |
| Jack the Snipper Ltd | Other services | 2024 |
| Jade Corporate Solutions Limited | Professional & scientific | 2002 |
| Jade Independent Financial Advisors Limited | Financial services | 2001 |
| Jade Life Limited | Financial services | 2002 |
| Jade Mitcham Property Limited | Construction | 2002 |
| Jade Mortgage Services Limited | Financial services | 2002 |
| JAG Ventures Ltd | Information & communication | 2017 |
| JAI Ganesh Corporate Ltd | Hospitality | 2026 |
| Jaival Consulting Limited | Information & communication | 2013 |
| Jaketvservice Ltd | Information & communication | 2019 |
| James & Co Property Limited | Real estate | 2026 |
| James Blackmore Electrical Ltd | Construction | 2024 |
| James Crabbe Design Ltd | Professional & scientific | 2018 |
| James Crabbe Photography Ltd | Professional & scientific | 2026 |
| James Russell & Sons (Photographers) Limited | Real estate | 1952 |
| James Selby Associates Limited | Information & communication | 2004 |
| James Watson Wealth Management Ltd | Financial services | 2019 |
| Janany Ltd | Administrative & support | 2016 |
| Jancett Childcare & Jace Training Limited | Education | 2007 |
| Janmar Trading Limited | Wholesale & retail | 1998 |
| Jaqmann Business Solutions Limited | Information & communication | 2018 |
| Javip Management Ltd | Professional & scientific | 2014 |
| JAY B Estate Agents Limited | Real estate | 2025 |
| Jayram Holdings Ltd | Real estate | 2020 |
| Jbba Consultancy Ltd | Professional & scientific | 2025 |
| JBW Heating Services Ltd | Construction | 2026 |
| JC & C Exchange Ltd | Administrative & support | 2024 |
| JC & C Properties Ltd | Real estate | 2023 |
| Jcll Investments Limited | Administrative & support | 2007 |
| Jcll Property Management Limited | Real estate | 2019 |
| JCM Property Development Limited | Households | 2024 |
| Jcpl Limited | Hospitality | 2024 |
| JD Autoworx Limited | Manufacturing | 2015 |
| JDC Productions Ltd | Other services | 2016 |
| JE Anaba Associates Limited | Other services | 2010 |
| Jeet Consulting Ltd | Information & communication | 2013 |
| Jefton Court Limited | Households | 1993 |
| Jenletto Ltd | Professional & scientific | 2022 |