| Irongate Data Protection Ltd | Information & communication | 2026 |
| Ironmasters Catering Ltd | Hospitality | 2025 |
| Isev Limited | Information & communication | 2008 |
| Isha & Preet Properties Ltd | Real estate | 2023 |
| ISI Traders Limited | Real estate | 2020 |
| ISL Property Services Ltd | Construction | 2017 |
| Isorenovate Limited | Construction | 2024 |
| Isps Associates Limited | Other services | 2014 |
| Istanbul 1 Barbers Ltd | Other services | 2021 |
| Istanbul's Barbers Ltd | Other services | 2021 |
| IT Equipment 575 Ltd | Wholesale & retail | 2026 |
| IT Equipment Ltd | Wholesale & retail | 2026 |
| Itech Brains Ltd | Wholesale & retail | 2025 |
| Itk.Digital Ltd | Professional & scientific | 2025 |
| Itransxpress Limited | Transport & logistics | 2023 |
| Itverse Limited | Information & communication | 2016 |
| Iulia Vasilescu Ltd | Other services | 2022 |
| Ivaniris Healthcare Limited | Health & social care | 2022 |
| Ivor P Enterprise Ltd Limited | Wholesale & retail | 2025 |
| Iwantworkwear Limited | Wholesale & retail | 2021 |
| Ixmidlands Limited | Information & communication | 2025 |
| Izurch Limited | Information & communication | 2021 |
| J & F Transport Ltd | Transport & logistics | 2019 |
| J & G Property Investments Limited | Real estate | 2016 |
| J & I Services Ltd | Construction | 2024 |
| J & L Consulting Ltd | Professional & scientific | 2024 |
| J & M Property Lettings Limited | Real estate | 2024 |
| J & P Clements Ltd | Information & communication | 2022 |
| J & R Escapes Limited | Administrative & support | 2025 |
| J & R Home Lettings Ltd | Real estate | 2021 |
| J & S Homes Limited | Real estate | 2017 |
| J a Mechanical Services Ltd | Construction | 2020 |
| J and C Catering Ltd | Hospitality | 2026 |
| J B Electrical & Maintenance Services Limited | Construction | 2019 |
| J C Morris Brickwork Ltd | Construction | 2020 |
| J D Metals Limited | Water & waste | 2008 |
| J Edwards Building Services Limited | Construction | 2019 |
| J Edwards Glass Limited | Construction | 2019 |
| J F Cars Ltd | Wholesale & retail | 2024 |
| J G Developments Limited | Real estate | 2011 |
| J Grant Catering Ltd | Hospitality | 2014 |
| J K K Contractors Ltd | Professional & scientific | 2013 |
| J M Bradshaw Consultancy Ltd | Professional & scientific | 2025 |
| J M Mason Limited | Professional & scientific | 2010 |
| J P Properties (Telford) Ltd | Real estate | 2021 |
| J P R Transport Ltd | Transport & logistics | 2014 |
| J Price Roofing Contractors Limited | Construction | 2013 |
| J Price TM Ltd | Construction | 2025 |
| J R Neale Ltd | Wholesale & retail | 2022 |
| J R O Griffiths Limited | Agriculture & fishing | 2003 |
| J R O Griffiths Marketing Limited | Extraterritorial | 2018 |
| J R Williams Funeral Director Limited | Other services | 2002 |
| J R Winter Properties Ltd | Real estate | 2026 |
| J Upton Storage Ltd | Other services | 2017 |
| J&A TAL Ltd | Transport & logistics | 2025 |
| J&B Creative Limited | Financial services | 2024 |
| J&C Safety Management Ltd | Construction | 2026 |
| J&J Baciu Ltd | Wholesale & retail | 2019 |
| J&J Elite Property Services Ltd | Real estate | 2022 |
| J&K Mark Ltd | Professional & scientific | 2024 |
| J&K Products Ltd | Manufacturing | 2024 |
| J&L Properties (Northern) Ltd | Real estate | 2005 |
| J&S Housing Ltd | Real estate | 2018 |
| J&S Techparts Ltd | Wholesale & retail | 2025 |
| J-Atm Logistic Ltd | Transport & logistics | 2018 |
| J. & M. Swindley Limited | Real estate | 1977 |
| J. Daniel Carpet & Flooring Limited | Construction | 2004 |
| J. Minton Plastering Services Ltd | Construction | 2002 |
| J. Richardson C.B.T. Limited | Health & social care | 2014 |
| J. Rodrigues Ltd | Health & social care | 2011 |
| J.A. Seals Ltd | Manufacturing | 2005 |
| J.B.P. Traders Limited | Construction | 2018 |
| J.C Housing Ltd | Real estate | 2022 |
| J.G. Merry Limited | Professional & scientific | 2011 |
| J.L. Price Properties Ltd | Real estate | 2020 |
| J.M Hughes Limited | Wholesale & retail | 2018 |
| J.M. Worthington & Co. Limited | Manufacturing | 1976 |
| J.N.H. Group Ltd | Professional & scientific | 2003 |
| J.W. Palmer & Sons (Newbury) Limited | Construction | 1949 |
| J4M54 Limited | Arts & recreation | 2012 |
| J5PSP Limited | Hospitality | 2025 |
| JA Chaggar Properties Ltd | Real estate | 2024 |
| JA Security & Services Ltd | Administrative & support | 2022 |
| Jaad Mechanical Limited | Professional & scientific | 2025 |
| JAB Ventures Ltd | Real estate | 2024 |
| Jack B Transport Ltd | Transport & logistics | 2021 |
| Jack Chase Limited | Manufacturing | 2013 |
| Jack Moody Properties Limited | Real estate | 2026 |
| Jack Moody's Limited | Wholesale & retail | 2000 |
| Jack's Flapjacks Ltd | Manufacturing | 2011 |
| Jackson & Lewis Limited | Wholesale & retail | 2019 |
| Jackson Pinto Ltd | Real estate | 2018 |
| Jackson Pinto Valuation Services Limited | Extraterritorial | 2018 |
| Jacob Chandler Limited | Manufacturing | 2019 |
| Jacobson Homez Ltd | Real estate | 2022 |
| JAD Farrier Limited | Professional & scientific | 2016 |
| Jaengineers Ltd | Manufacturing | 2022 |
| Jagc Limited | Wholesale & retail | 2025 |
| Jagga & Sons Ltd | Wholesale & retail | 2022 |
| Jaitt Limited | Real estate | 2015 |