| JDM Midlands Ltd | Financial services | 2022 |
| JDP Transports Limited | Transport & logistics | 2025 |
| Jean & Moon Ltd | Manufacturing | 2022 |
| Jeavons Landscapes Limited | Administrative & support | 2002 |
| Jeavons Roofing Services Limited | Construction | 2006 |
| Jeer Homes Ltd | Real estate | 2022 |
| Jeff Jones Auto Services Ltd | Wholesale & retail | 2003 |
| Jeffcock Chippy Ltd | Other services | 2014 |
| Jeggo & Jeggo Limited | Professional & scientific | 2014 |
| JEL Executive Enterprise Ltd | Administrative & support | 2025 |
| Jellings Dalton Group Limited | Financial services | 2015 |
| Jellings Dalton Investments Limited | Financial services | 2015 |
| JEM18 Group Limited | Financial services | 2026 |
| Jemima's Caring Hands Limited | Hospitality | 2023 |
| Jen's Friends Limited | Wholesale & retail | 2020 |
| Jenben Holdings Ltd | Financial services | 2024 |
| Jenson Corporation Ltd. | Manufacturing | 1995 |
| JER Capital Ltd | Financial services | 2026 |
| JER Services Ltd | Information & communication | 2026 |
| Jerda Limited | Professional & scientific | 2013 |
| Jeremiah Properties Ltd | Real estate | 2023 |
| Jeremy Nicholls Golf Limited | Administrative & support | 2017 |
| Jerk & Sizzle Ltd | Hospitality | 2025 |
| Jerm Limited | Health & social care | 2012 |
| Jerrams Roofing and Building Ltd | Construction | 2021 |
| Jerusalem Beauty Ltd | Wholesale & retail | 2024 |
| Jervid Property Services Ltd | Real estate | 2024 |
| Jeseco International Limited | Wholesale & retail | 1993 |
| Jesieevents Ltd | Hospitality | 2025 |
| Jessaudre Ltd | Information & communication | 2023 |
| Jessexcel Ltd | Wholesale & retail | 2020 |
| Jesvic Ltd | Wholesale & retail | 2023 |
| JET 1 Services Limited | Transport & logistics | 2003 |
| JET Engineering (UK) Limited | Administrative & support | 2003 |
| JET Wash Car Wash Ltd | Administrative & support | 2026 |
| Jetblack Properties Limited | Real estate | 2025 |
| Jetlaser Limited | Administrative & support | 2017 |
| Jetowash Limited | Administrative & support | 2017 |
| Jetset Rides Limited | Transport & logistics | 2024 |
| Jetyou Limited | Transport & logistics | 2018 |
| Jevezi Ltd | Health & social care | 2023 |
| Jevitt Consulting Ltd | Professional & scientific | 2025 |
| Jevlock Engineering Limited | Administrative & support | 1976 |
| Jewade Graham Coaching Ltd | Arts & recreation | 2017 |
| Jewels Cleaning Ltd | Administrative & support | 2023 |
| Jeylee Holdings Limited | Mining & quarrying | 2021 |
| JEZ Moxey Consulting Limited | Other services | 2017 |
| JF Property Procurements Ltd | Real estate | 2025 |
| JF Retail Supplies Ltd | Wholesale & retail | 2022 |
| JFD Trading Ltd | Administrative & support | 2018 |
| JFG Properties Limited | Real estate | 2026 |
| JFK Worldwide Ltd | Extraterritorial | 2023 |
| JFW Design & Development Ltd | Professional & scientific | 2022 |
| JFW Property & Development Ltd | Real estate | 2021 |
| JG Enterprises U.K. Limited | Professional & scientific | 2021 |
| JG Home Improvement Services Ltd | Construction | 2019 |
| JG Refrigeration Ltd | Construction | 2023 |
| JGK Refurbishment Ltd | Construction | 2026 |
| JGR Construction Ltd | Construction | 2020 |
| JH Carrier Ltd | Transport & logistics | 2026 |
| JH Counselling Solutions Limited | Health & social care | 2020 |
| JH Investment Holdings Ltd | Real estate | 2022 |
| JH Tattoos Ltd | Other services | 2025 |
| Jhalli Properties Ltd | Real estate | 2022 |
| Jhamat Properties Ltd | Real estate | 2025 |
| Jhangra Estates Ltd | Real estate | 2023 |
| Jhclh Limited | Professional & scientific | 2026 |
| Jhsb Properties Limited | Real estate | 2024 |
| JIA YAN Ltd | Hospitality | 2025 |
| JIF Limited | Transport & logistics | 2020 |
| Jigsaw Arts (Broxbourne) Ltd | Arts & recreation | 2019 |
| Jigsaw Arts (Ware-Hertford) Ltd | Arts & recreation | 2021 |
| Jigsaw Home Development Ltd | Construction | 2022 |
| JIM Gough Limited | Wholesale & retail | 1960 |
| Jinx Gaming Ltd | Information & communication | 2024 |
| Jisara Collections Ltd | Wholesale & retail | 2025 |
| Jitt Construction Ltd | Construction | 2023 |
| Jitt Group Ltd | Financial services | 2023 |
| Jitt Investment Ltd | Hospitality | 2023 |
| Jitt Properties Ltd | Real estate | 2023 |
| Jitt Wholesales Ltd | Wholesale & retail | 2023 |
| Jivans Indian Food Limited | Hospitality | 2013 |
| Jiwan Chakra Investment Limited | Real estate | 2024 |
| JJ & N Associates Limited | Professional & scientific | 2007 |
| JJ Assets Ltd | Real estate | 2024 |
| JJ Care and Homes Ltd | Health & social care | 2025 |
| JJ Castings Limited | Manufacturing | 2003 |
| JJ Fitness & Nutrition Ltd | Arts & recreation | 2025 |
| JJ Motors Limited | Wholesale & retail | 2026 |
| JJ Nasy Limited | Wholesale & retail | 2023 |
| JJ Tours Ltd | Transport & logistics | 2025 |
| JJ Transporter Ltd | Transport & logistics | 2016 |
| JJ Tyres Limited | Wholesale & retail | 2023 |
| JJ UK Properties Ltd | Real estate | 2020 |
| JJA Hill Properties Limited | Real estate | 2026 |
| Jjass Go Grub Limited | Hospitality | 2025 |
| Jjmmedical Ltd | Health & social care | 2023 |
| JJS Investments Ltd | Construction | 2019 |
| JJW Enterprises Ltd | Hospitality | 2026 |
| JK Builders and Renovations Limited | Construction | 2024 |