| J R Carpentry & Construction Contractors Limited | Construction | 2019 |
| J R D Bipel Ltd | Manufacturing | 1992 |
| J R Main Holdings Ltd | Financial services | 2025 |
| J R Marshall Brickwork Ltd | Construction | 2022 |
| J S Bains Transport Limited | Transport & logistics | 2014 |
| J S Dhillon Transport Limited | Transport & logistics | 2015 |
| J S Moore Ltd | Real estate | 2012 |
| J T a Health Care Limited | Health & social care | 2022 |
| J Turner Holdings Ltd | Financial services | 2023 |
| J W Mobility Limited | Wholesale & retail | 2005 |
| J Walker Heating & Plumbing Ltd | Construction | 2022 |
| J Walton Services Limited | Other services | 2024 |
| J& J Projects Ltd | Construction | 2025 |
| J&Aproducts Ltd | Wholesale & retail | 2024 |
| J&B Medical and Security Services Limited | Administrative & support | 2024 |
| J&C Scaffolding Solutions Limited | Construction | 2010 |
| J&Daughters Ltd | Wholesale & retail | 2023 |
| J&J Electrical Contracts Ltd | Construction | 2025 |
| J&J Environmental Services Ltd | Professional & scientific | 2023 |
| J&J Mason Property Ltd | Real estate | 2023 |
| J&L Timber Fencing Ltd | Wholesale & retail | 2024 |
| J&L Timber Ltd | Wholesale & retail | 2024 |
| J&N UK Properties Ltd | Real estate | 2024 |
| J&Noor Brothers Ltd | Transport & logistics | 2025 |
| J&S Civil Engg Ltd | Construction | 2022 |
| J&S Keown Properties Limited | Construction | 2024 |
| J&T Crest Properties Limited | Households | 2024 |
| J'S Barber Shop Ltd | Other services | 2019 |
| J. and M. Hall Transport (1983) Limited | Information & communication | 1983 |
| J. and M. Harris (Eggs and Cheese) Limited | Wholesale & retail | 1976 |
| J. Hall & SON (Fasteners) Limited | Wholesale & retail | 1970 |
| J. Mills Building & Roofing Limited | Construction | 2006 |
| J.B.K 2025 Realisations Limited | Wholesale & retail | 1906 |
| J.Beech Plastering Ltd | Construction | 2023 |
| J.C. Engineering (UK) Ltd | Professional & scientific | 2001 |
| J.E.B. Commercial & Car Limited | Wholesale & retail | 2006 |
| J.H.Holland Limited | Real estate | 1962 |
| J.H.Richards and Co.Limited | Manufacturing | 1915 |
| J.J. Commercials Limited | Wholesale & retail | 2008 |
| J.K.D. Engineering (Kidsgrove) Limited | Arts & recreation | 1975 |
| J.P. Metal Treatments Limited | Manufacturing | 1971 |
| J.P.L. Fire and Security Limited | Manufacturing | 2011 |
| J.S.Matthews Landscapes Ltd | Administrative & support | 2024 |
| J.T.C. Associates Limited | Information & communication | 1989 |
| J.W. Trans Ltd | Transport & logistics | 2013 |
| J2BAS Limited | Professional & scientific | 2022 |
| J4HC Limited | Health & social care | 2016 |
| J9 Aggregates Ltd | Water & waste | 2024 |
| Jaat Ltd | Wholesale & retail | 2026 |
| JAB Accountants Ltd | Professional & scientific | 2022 |
| JAB Robotic Services Ltd | Manufacturing | 2012 |
| Jabateh Family Limited | Health & social care | 2018 |
| Jack & Ada's Limited | Hospitality | 2020 |
| Jack Burrows & Sons Limited | Manufacturing | 2002 |
| Jack Fulton Limited | Professional & scientific | 1988 |
| Jack Walter Property Ltd | Real estate | 2025 |
| Jackal Consultants Ltd | Professional & scientific | 2016 |
| Jackson Maintenance Ltd | Construction | 2016 |
| Jackson & Sons Limited | Construction | 2008 |
| Jackson Brooke Properties Ltd | Households | 2025 |
| Jackwolf Electrical Limited | Construction | 2026 |
| Jackwolf Energy Limited | Construction | 2025 |
| Jackwolf Group Holdings Limited | Financial services | 2024 |
| Jackwolf Group Limited | Construction | 2019 |
| Jackwolf Limited | Real estate | 2023 |
| Jackwolf Projects Limited | Construction | 2025 |
| Jacob&Co Construction Ltd | Construction | 2026 |
| Jacobs & Thompson Holdco UK Limited | Manufacturing | 2020 |
| Jacobsrd Ltd | Wholesale & retail | 2026 |
| Jadom Limited | Health & social care | 2023 |
| Jadore Accesorize Ltd | Extraterritorial | 2023 |
| JAG Powerworks Ltd | Construction | 2025 |
| JAH Hold Co Ltd | Financial services | 2021 |
| JAH Oral Care Ltd | Health & social care | 2021 |
| JAH Properties Ltd | Real estate | 2021 |
| Jahangir Welfare Trust | Health & social care | 2010 |
| Jaika Interactive Limited | Information & communication | 2018 |
| Jaip Ltd | Health & social care | 2026 |
| Jaipur Balti Lounge Ltd | Hospitality | 2018 |
| Jakdor Limited | Manufacturing | 2009 |
| Jakeeem Ltd | Information & communication | 2016 |
| Jalalia Sunni Jami Masjid & Islamic Education Centre | Education | 2005 |
| Jalaram Homes Limited | Real estate | 2024 |
| Jalebae&Co. Ltd | Hospitality | 2022 |
| Jalf Holdings Ltd | Wholesale & retail | 2023 |
| Jalf Video Production Limited | Information & communication | 2020 |
| Jalil Cars and Parts Ltd | Water & waste | 2026 |
| JAM Solutions International Ltd. | Wholesale & retail | 2022 |
| Jameel & Sons Builders Ltd | Construction | 2025 |
| James & Lees Installations Ltd | Construction | 2024 |
| James Associates (Midlands) Limited | Manufacturing | 2002 |
| James Capital Ltd | Real estate | 2019 |
| James Cotterell & Sons Limited | Manufacturing | 1946 |
| James Fields IT Services Ltd | Information & communication | 2025 |
| James Hewitt Maintenance Welding & Fabrication Ltd | Other services | 2023 |
| James Kidd Ltd | Real estate | 2025 |
| James Price's Garage Ltd | Wholesale & retail | 2025 |
| Jamie Christopher Limited | Wholesale & retail | 2020 |
| Jamiesproperty Ltd | Real estate | 2026 |
| Jamshid Amir Ltd | Wholesale & retail | 2025 |