| JET Care Limited | Public administration | 2024 |
| JET Class Travel Limited | Transport & logistics | 2025 |
| JET Interior Contracts Limited | Construction | 2016 |
| JET Property and Investment Group Ltd | Real estate | 2024 |
| JET Property Lettings Ltd | Real estate | 2020 |
| Jetcentric Ltd | Wholesale & retail | 2023 |
| Jetclean Environmental Limited | Administrative & support | 2023 |
| Jetman Building Services Ltd | Construction | 2023 |
| Jetman Property Ltd | Real estate | 2024 |
| Jetsmart Solutions Limited | Construction | 2025 |
| Jetstone Publishers Ltd | Wholesale & retail | 2017 |
| Jewel Digital Limited | Professional & scientific | 2020 |
| Jewelicious Limited | Wholesale & retail | 2024 |
| Jewell Construction Holdings Limited | Financial services | 2025 |
| Jewellery in Wonderland Limited | Wholesale & retail | 2022 |
| Jeya Construction Ltd | Construction | 2025 |
| Jezdes Homes Ltd | Real estate | 2023 |
| JF Engineering Services Limited | Administrative & support | 2005 |
| JF Innovations Ltd | Information & communication | 2025 |
| Jfiv Limited | Financial services | 2025 |
| JFL Limited | Professional & scientific | 1990 |
| JFM Consultancy Ltd | Professional & scientific | 2023 |
| JFP Notts Ltd | Construction | 2024 |
| JFP2 Ltd | Construction | 2025 |
| JFR Security Ltd | Administrative & support | 2025 |
| Jfrw Limited | Financial services | 2024 |
| JFS Solutions Ltd | Construction | 2021 |
| JG Chair Side Services Ltd | Health & social care | 2018 |
| JG Quality Supplies Limited | Administrative & support | 2012 |
| Jgbi Holding Ltd | Real estate | 2026 |
| Jgbi Ltd | Other services | 2022 |
| JGP Management Limited | Financial services | 2018 |
| JGS Holdings Group Limited | Financial services | 2025 |
| JGS NG Properties Ltd | Real estate | 2025 |
| Jgtx Ltd | Transport & logistics | 2024 |
| JGW Estates Ltd | Real estate | 2020 |
| JH Accounts Ltd | Professional & scientific | 2023 |
| JH Arbitrage Ltd | Wholesale & retail | 2024 |
| JH Clinical Training Ltd | Education | 2024 |
| JH Engineering Services Limited | Professional & scientific | 2006 |
| JH Office Install Ltd | Construction | 2023 |
| JH Property Lets Ltd | Real estate | 2025 |
| JH Reconditioning Limited | Real estate | 2013 |
| JH RSS Ltd | Professional & scientific | 2019 |
| JH Training Ltd | Education | 2024 |
| Jh&M Hair and Beauty Ltd | Administrative & support | 2021 |
| Jhall & Sons Limited | Hospitality | 2012 |
| JHB Direct Limited | Wholesale & retail | 2023 |
| JHC Trading Ltd | Wholesale & retail | 2024 |
| Jhcomm Ltd | Professional & scientific | 2024 |
| Jhdmservices Ltd | Construction | 2026 |
| Jhira Sahib Courier Limited | Transport & logistics | 2025 |
| JHL Construction and Bricks Limited | Construction | 2023 |
| JHL Estates Limited | Real estate | 1955 |
| JHM Management Limited | Professional & scientific | 2016 |
| Jhsl Limited | Administrative & support | 2019 |
| Jhsound Limited | Information & communication | 2003 |
| Jhss PVT Ltd | Wholesale & retail | 2019 |
| Jhst Ltd | Professional & scientific | 2024 |
| Jhuskisson Ltd | Information & communication | 2010 |
| JHW Consultancy Ltd | Information & communication | 2013 |
| JHWCC25 Ltd | Professional & scientific | 2025 |
| JIA Housing Ltd | Real estate | 2020 |
| Jiajie Property Ltd | Real estate | 2020 |
| Jibin Johnson Ltd | Administrative & support | 2025 |
| Jibron Limited | Wholesale & retail | 2025 |
| Jigiweb CIC | Information & communication | 2026 |
| Jigsaw Estimating Limited | Professional & scientific | 2025 |
| Jigsaw Kitchens Limited | Construction | 2002 |
| Jigsaw Property Management Ltd | Real estate | 2018 |
| Jigsaw Property Solutions Limited | Real estate | 2017 |
| Jigsaw Systems Limited | Wholesale & retail | 1992 |
| Jigsaw Therapeutic Care Ltd | Health & social care | 2017 |
| Jigsaw Therapeutic Care Services Limited | Health & social care | 2020 |
| JIGSAW24 Limited | Extraterritorial | 1992 |
| Jijgee MGL Ltd | Hospitality | 2021 |
| JIK Properties Limited | Real estate | 2023 |
| Jikkart Ltd | Wholesale & retail | 2025 |
| JIL Developments Limited | Real estate | 2012 |
| Jill Carter Consultancy Limited | Professional & scientific | 2019 |
| Jill Saward Ltd | Information & communication | 2022 |
| Jill-Iyke Ltd | Health & social care | 2021 |
| Jilly and MAY Limited | Public administration | 2026 |
| JIM and Claire Limited | Real estate | 2009 |
| JIM Budnik Ltd | Transport & logistics | 2021 |
| JIM Connolly Photography Ltd | Professional & scientific | 2020 |
| JIM Rowe-Bot Ltd | Administrative & support | 2012 |
| Jimbos Lenton Ltd | Hospitality | 2018 |
| Jimbos Nottingham Ltd | Hospitality | 2025 |
| Jimsons Limited | Real estate | 2003 |
| Jinda Biant Limited | Health & social care | 2014 |
| Jing Chang Enterprise Limited | Real estate | 2010 |
| Jinky Farms Limited | Agriculture & fishing | 2022 |
| Jinny Investments Limited | Real estate | 2017 |
| Jioberi Limited | Real estate | 2024 |
| Jireh GMB Limited | Health & social care | 2024 |
| Jisan Ahmad Ltd | Wholesale & retail | 2025 |
| Jisu Velocity Ltd | Transport & logistics | 2024 |
| Jit's Kitchen Limited | Hospitality | 2025 |
| Jiyan Fresh Limited | Other services | 2023 |