| Independent Yacht Charter Ltd | Administrative & support | 2017 |
| Indigo Design Associates Limited | Professional & scientific | 2003 |
| Industrial Automation Solutions Ltd | Professional & scientific | 2018 |
| Infinite Arch Limited | Information & communication | 2021 |
| Ingleby (2030) Limited | Financial services | 2019 |
| INK Free LLP | | 2015 |
| Inmere NET Limited | Information & communication | 2007 |
| Innisfree Investments Park Homes Ltd | Extraterritorial | 2010 |
| Innmedia Ltd | Information & communication | 2024 |
| Innovation Installations (KL) Limited | Extraterritorial | 2018 |
| Innovation Installations Limited | Construction | 2011 |
| Innovative Solution Group Ltd | Wholesale & retail | 2024 |
| Inorcam Limited | Professional & scientific | 2019 |
| Inovara Ltd | Transport & logistics | 2014 |
| Inpac Limited | Wholesale & retail | 2021 |
| Inshore Linen Ltd | Administrative & support | 2023 |
| Inshore Living Ltd | Administrative & support | 2020 |
| Insideout Home Stores Ltd | Wholesale & retail | 2013 |
| Insight EYE Publishing Ltd | Information & communication | 2023 |
| Inspired Business Limited | Other services | 2022 |
| Instrumentbk Limited | Administrative & support | 2017 |
| Instyle Decor Professional Decorating Services Ltd | Administrative & support | 2010 |
| Insynthesis Limited | Wholesale & retail | 2019 |
| Integrative Health Acupuncture Limited | Health & social care | 2023 |
| Intelligent Chimney Solutions Ltd | Administrative & support | 2021 |
| Intellomx Limited | Information & communication | 2026 |
| Interim Management Results Limited | Administrative & support | 2008 |
| Invello Ltd | Professional & scientific | 2021 |
| Invictus Financial Ltd | Real estate | 2022 |
| Invivian Limited | Construction | 2021 |
| Iris Healthcare Ltd | Health & social care | 2026 |
| Iron & Brass BED Company Limited | Manufacturing | 2018 |
| Iron Industries Limited | Manufacturing | 2012 |
| Ironsafe Scaffold Labour Ltd | Construction | 2026 |
| Irvines Construction Ltd | Construction | 2017 |
| Irving's Property Management Limited | Construction | 2018 |
| Ishine Technology Ltd | Manufacturing | 2010 |
| Istay Here Ltd | Real estate | 2018 |
| IT Mortgages Ltd | Financial services | 2025 |
| Italsed UK Limited | Wholesale & retail | 2007 |
| Itelematix Limited | Information & communication | 2016 |
| Itrust Medical Services Limited | Wholesale & retail | 2015 |
| ITZ Transport Solution Ltd | Transport & logistics | 2026 |
| IVY Build & Property Maintenance Ltd | Construction | 2026 |
| IVY Cottage Bees Ltd | Manufacturing | 2021 |
| IVY Rock Creations Ltd | Wholesale & retail | 2022 |
| IW Finance Limited | Financial services | 2019 |
| J & J Tree Services Ltd | Other services | 2013 |
| J & M Systems Ltd | Professional & scientific | 2016 |
| J a Brooks Electrical Ltd | Construction | 2023 |
| J B C Commercial Roofing Limited | Construction | 2006 |
| J C Wood Ltd | Construction | 2003 |
| J Catering Limited | Hospitality | 2017 |
| J Dixon Consultancy Ltd | Professional & scientific | 2023 |
| J Fredricks Limited | Administrative & support | 2018 |
| J G Taylor Ltd | Construction | 2021 |
| J J a Control Systems Limited | Professional & scientific | 2011 |
| J M Grange Ltd | Construction | 2012 |
| J Massingham Plastering Limited | Construction | 2024 |
| J Mccandles Limited | Wholesale & retail | 2025 |
| J N TEC Ltd | Manufacturing | 2021 |
| J O & D Properties Limited | Real estate | 2024 |
| J R Mann Builders Limited | Construction | 2019 |
| J S Means (Terrington) Limited | Agriculture & fishing | 2010 |
| J SE Nwobodo Limited | Financial services | 2022 |
| J Shewring Haulage Limited | Transport & logistics | 2014 |
| J Stone Consulting Limited | Other services | 2020 |
| J Suckling Rentals Ltd | Real estate | 2024 |
| J W Holmes Site Management Ltd | Professional & scientific | 2024 |
| J&H Property Limited | Real estate | 2024 |
| J. & K. Aluminium Ltd | Construction | 2021 |
| J. & K. Glass & Glazing Limited | Construction | 1988 |
| J. Blude (Cladding Specialists) Limited | Construction | 2005 |
| J. Goodley & Sons Limited | Agriculture & fishing | 1960 |
| J. Suckling Developments Limited | Construction | 2000 |
| J.A.K & Sons Bodyshop Ltd | Wholesale & retail | 2024 |
| J.A.K Workshop Limited | Wholesale & retail | 2026 |
| J.A.Needham Limited | Agriculture & fishing | 1960 |
| J.B.C. Roofing Limited | Construction | 2001 |
| J.C. Hammond Limited | Wholesale & retail | 1985 |
| J.E.C.Powell Limited | Real estate | 1957 |
| J.F.T. Maintenance Services Limited | Construction | 2008 |
| J.R. Major Limited | Real estate | 2005 |
| J.S. D'Aloia Builders Limited | Construction | 2006 |
| J6 Developments Ltd | Manufacturing | 2018 |
| JAC PM Ltd | Construction | 2021 |
| Jacal Holdings Limited | Wholesale & retail | 2025 |
| Jacaranda Construction Limited | Extraterritorial | 2023 |
| Jackson Builders Ltd Ltd | Construction | 2024 |
| Jackson Resolutions Ltd | Health & social care | 2016 |
| Jacobs Consulting Limited | Information & communication | 2007 |
| JAF Properties Limited | Real estate | 2025 |
| Jake Stansfield Ltd | Construction | 2013 |
| Jalapeno Business Services Newark Ltd | Information & communication | 2011 |
| James & Sons (Auctioneers) Limited | Extraterritorial | 2008 |
| James England Limited | Construction | 2007 |
| James Figg Limited | Wholesale & retail | 2023 |
| James French Solutions Limited | Transport & logistics | 2015 |
| James Hartley (Poppylot Farms) Limited | Agriculture & fishing | 1957 |
| James Lynne Limited | Professional & scientific | 2022 |