| Jobec UK Ltd | Manufacturing | 2023 |
| Jofson Ultimate Topco Limited | Financial services | 2025 |
| Johal Brothers Transport Limited | Transport & logistics | 2006 |
| Johal Landmark Homes Ltd | Construction | 2019 |
| Johal's Property Investment Ltd | Real estate | 2022 |
| John Burn Castings Ltd | Manufacturing | 2020 |
| John COX Cold Stores and Distribution Services Limited | Manufacturing | 1981 |
| John Hill & Sons (Walsall) Limited | Wholesale & retail | 1957 |
| John Smith & Co.(Derby)Limited | Manufacturing | 1899 |
| John Taylor Production Services Limited | Arts & recreation | 2009 |
| John Wilkes Electrical Limited | Manufacturing | 1965 |
| John Wilkinson Heating Services Ltd | Manufacturing | 2011 |
| John-Blair Enterprise Ltd | Professional & scientific | 2026 |
| Johnson Plastering & Building Contractors Limited | | 1984 |
| Johny Ace Painters Limited | Construction | 2024 |
| Joinery Shop Solutions Ltd | Construction | 2013 |
| Jojo's PIT Stop Ltd | Hospitality | 2026 |
| Jojos Tea & Coffee Emporium Ltd | Wholesale & retail | 2024 |
| Jonas G Painter & Decorator Limited | Other services | 2020 |
| Jonathan Steven Morris Ltd | Health & social care | 2025 |
| Jonathan Walker & Associates Limited | Health & social care | 2003 |
| Jones & Smith Properties Limited | Real estate | 2019 |
| Jones & Woodhouse Developments Limited | Construction | 2019 |
| Jones Contracts Limited | Construction | 1999 |
| Jones Motor Group Ltd | Wholesale & retail | 2025 |
| Jones Weatherproofing Limited | Construction | 1993 |
| Jones Window Maintenance Ltd | Construction | 2024 |
| Jordan Narey Ltd | Information & communication | 2025 |
| Jordans Heating Limited | Construction | 2018 |
| Jordan’S Property Services Limited | Construction | 2025 |
| Josakki Realtors Ltd | Real estate | 2025 |
| Joseph and Frank Ltd | Real estate | 2025 |
| Joseph Carver Limited | Extraterritorial | 1994 |
| Josh International Trading Limited | Wholesale & retail | 2025 |
| Josh K Ventures Limited | Wholesale & retail | 2018 |
| Josh Ranford Roofing Ltd | Construction | 2024 |
| Josh Wildman Limited | Construction | 2019 |
| Joshi Consulting Ltd | Professional & scientific | 2010 |
| Joshua Lewis Ltd | Construction | 2025 |
| Josie Hastings Associates Ltd | Administrative & support | 2012 |
| JOT Bros Ltd | Transport & logistics | 2024 |
| Jove Contracts Ltd | Construction | 2021 |
| Jove Holdings Limited | Financial services | 2022 |
| Joybangla Eatery Ltd | Hospitality | 2025 |
| Joymok Hair and Beauty Ltd | Other services | 2024 |
| Joyneste Care Ltd | Health & social care | 2024 |
| JP Coureir Ltd | Transport & logistics | 2021 |
| JP Instruments Limited | Wholesale & retail | 2015 |
| JP Kindom Limited | Financial services | 2025 |
| Jparkermetalwork Ltd | Manufacturing | 2019 |
| JPC Holdings WM Ltd | Financial services | 2025 |
| JPE Electrical Services Ltd | Construction | 2021 |
| JPL Security Systems Ltd | Construction | 2023 |
| JPR UK Enterprises Ltd | Information & communication | 2021 |
| JPT Transport Limited | Transport & logistics | 2020 |
| JQ Luxe Steam & Bean Ltd | Hospitality | 2025 |
| JR Chilli Limited | Wholesale & retail | 2016 |
| JR Electrical Solutions Ltd | Manufacturing | 2022 |
| JR Fireworks Ltd | Other services | 2025 |
| JR Optometry Services Limited | Health & social care | 2012 |
| JR Properties Investment Ltd | Real estate | 2026 |
| JR Uddin Ltd | Real estate | 2026 |
| Jreal Ltd | Real estate | 2018 |
| Jrfa Innovations Ltd | Health & social care | 2023 |
| Jrjs Limited | Professional & scientific | 2024 |
| Jroi Limited | Wholesale & retail | 2015 |
| Jrrs Tutors Ltd | Education | 2025 |
| JS Foodz Limited | Hospitality | 2023 |
| JS Property Management Services Limited | Real estate | 2016 |
| JS Residential Property Limited | Real estate | 2018 |
| JSD Productions Ltd | Information & communication | 2025 |
| JSD Roofing and Cladding Limited | Construction | 2024 |
| JSF Racing Ltd | Arts & recreation | 2025 |
| JSF Stainless Limited | Manufacturing | 2002 |
| JSH Pharma Ltd | Health & social care | 2021 |
| JSI Super Store Ltd | Wholesale & retail | 2024 |
| JSK and Sons Ltd | Hospitality | 2024 |
| JSK Buildings Limited | Construction | 2019 |
| JSK Cleaning Solutions Ltd | Administrative & support | 2023 |
| JSK Dhesi Limited | Transport & logistics | 2025 |
| JSK Limited | Manufacturing | 2006 |
| Jskp Properties Ltd | Real estate | 2022 |
| JSM Couriers Ltd | Transport & logistics | 2016 |
| JSM Propco Limited | Real estate | 2025 |
| JSN Transport Ltd | Transport & logistics | 2020 |
| JSR Fulfilment Limited | Wholesale & retail | 2026 |
| JSS Bookkeeping Services Ltd | Professional & scientific | 2014 |
| JSS Executive Ltd | Transport & logistics | 2023 |
| JSS Studios Ltd | Information & communication | 2024 |
| JT Barrows Property Investments Ltd | Real estate | 2026 |
| JT UK Properties Limited | Real estate | 2023 |
| JTC Carpentry Services Ltd | Manufacturing | 2020 |
| JTR Electrical Ltd | Other services | 2012 |
| JTS Energy Consultants Ltd | Professional & scientific | 2024 |
| Judith Limited | Wholesale & retail | 2023 |
| Jugravu Ltd | Transport & logistics | 2017 |
| Jujenn Retail Limited | Wholesale & retail | 2023 |
| Julia B Wellness Ltd | Professional & scientific | 2024 |
| Juliann Ltd | Transport & logistics | 2015 |
| Jumik Ltd | Health & social care | 2024 |