| JDB GRP Ltd | Financial services | 2022 |
| Jdcoder Ltd | Information & communication | 2022 |
| JDS Recruitment Limited | Administrative & support | 2015 |
| Jdsj Management Ltd | Extraterritorial | 2018 |
| Jdsl Business Management Ltd | Administrative & support | 2025 |
| JDW Consultancy Services Limited | Professional & scientific | 2022 |
| JEB Recoveries LLP | | 2014 |
| Jedshod Ltd | Real estate | 2025 |
| Jefford Consultancy Ltd | Professional & scientific | 2025 |
| Jega Holdings Limited | Professional & scientific | 2023 |
| Jelo Clothing Ltd | Manufacturing | 2019 |
| Jem's DRY Cleaners Limited | Other services | 2004 |
| Jemcoe Limited | Administrative & support | 2012 |
| Jenivia Limited | Real estate | 2019 |
| Jenny's Bloomers Ltd | Wholesale & retail | 2025 |
| Jenson Fisher Consulting Limited | Administrative & support | 2012 |
| Jerk Bros Limited | Hospitality | 2018 |
| JES Advisory Ltd | Professional & scientific | 2015 |
| Jessica House Developments Limited | Construction | 2015 |
| Jessica Wright Limited | Administrative & support | 2012 |
| JET Pack Productions Ltd | Professional & scientific | 2017 |
| JF MOI Management Limited | Professional & scientific | 2016 |
| Jfarey Visuals Limited | Professional & scientific | 2026 |
| JFB Catering Ltd | Hospitality | 2026 |
| Jfff Investment (UK) Limited | Real estate | 2021 |
| JFL Building Ltd | Construction | 2016 |
| JG Services(Essex) Limited | Professional & scientific | 2024 |
| Jgbk Ltd | Real estate | 2016 |
| JGD Heating & Plumbing Limited | Construction | 2016 |
| JH Contract Services (2012) Limited | Construction | 2012 |
| JH Multi Works Limited | Construction | 2025 |
| Jhetair Developments Limited | Real estate | 2022 |
| Jhetam Plant & Haulage Hire Limited | Administrative & support | 2026 |
| Jimmy's Barbers 53 the Broadway Limited | Other services | 2024 |
| Jiren Business Consulting Limited | Professional & scientific | 2025 |
| JJB Brickwork Ltd | Construction | 2010 |
| Jjfe Consulting Limited | Education | 2018 |
| JJM Estates Ltd | Real estate | 2014 |
| JJN Electronics Limited | Manufacturing | 2013 |
| JKM Property Maintenance Ltd | Construction | 2025 |
| JLM Enterprises Limited | Professional & scientific | 2021 |
| JLP Urology Limited | Health & social care | 2017 |
| JLS (Redditch) Limited | Manufacturing | 2005 |
| JLV Investments Ltd | Financial services | 2016 |
| JM 8 Ball Ltd | Real estate | 2019 |
| JM Bars Ltd | Hospitality | 2022 |
| Jm&M London Limited | Administrative & support | 2023 |
| JMC Collective Limited | Wholesale & retail | 2018 |
| JMC Industrial Units Limited | Real estate | 2017 |
| JMD Simply Gardens Limited | Professional & scientific | 2022 |
| JMF Maintenance Ltd | Construction | 2022 |
| JMK Lighting Limited | Information & communication | 2012 |
| JMR Motor Group Ltd | Wholesale & retail | 2023 |
| JMS Roofing Ltd | Construction | 2024 |
| JN Real Asset Investment Limited | Real estate | 2023 |
| JNB Motors Ltd | Wholesale & retail | 2024 |
| Joanne-Emma Obey Limited | Extraterritorial | 2025 |
| Jobdan UK Ltd | Construction | 2024 |
| Jodt Services Ltd | Administrative & support | 2022 |
| Jody Taylor Hair Ltd | Other services | 2021 |
| JOE Harding Properties Ltd | Real estate | 2020 |
| JOE W Martin Electrical Services Ltd | Professional & scientific | 2025 |
| JOEJEN2020 Limited | Real estate | 2020 |
| John Misca Plastering Ltd | Construction | 2015 |
| Johnson AS Ltd | Administrative & support | 2022 |
| Johnson PF Holdings Ltd | Financial services | 2016 |
| Johnson PF NO.1 Ltd | Financial services | 2023 |
| Johnson PF NO.2 Ltd | Administrative & support | 2023 |
| Jojr Investments Limited | Real estate | 2020 |
| Jojr Ltd | Information & communication | 2019 |
| Jolly Fine Pubs Ltd. | Hospitality | 2010 |
| Jonathan Leckey Consulting Limited | Professional & scientific | 2025 |
| Jonny James Stunts Ltd | Professional & scientific | 2018 |
| Josh & Lolly Limited | Real estate | 2005 |
| Josh Edwards Ltd | Arts & recreation | 2021 |
| Jost Property Limited | Real estate | 2024 |
| Jost Services Ltd | Administrative & support | 2022 |
| Jota Way Ltd | Administrative & support | 2022 |
| Joydeal Limited | Professional & scientific | 1990 |
| Joyful Souls Limited | Wholesale & retail | 2018 |
| Joypots Limited | Wholesale & retail | 2016 |
| JP INT Ltd | Construction | 2024 |
| JPD Caterer Ltd | Hospitality | 2024 |
| JPD Industries Ltd | Financial services | 2024 |
| JR Legal Enterprises Limited | Administrative & support | 2014 |
| Jrgk Property Ltd | Real estate | 2020 |
| JRK Bros. Limited | Hospitality | 2020 |
| JRK Bros.Events Ltd | Hospitality | 2021 |
| JRM Properties Ltd | Real estate | 2023 |
| JS Web Solution Ltd | Information & communication | 2022 |
| JSF Services (London) Ltd | Construction | 2018 |
| JSK (Chelmsford) Ltd | Real estate | 2021 |
| Jspm Maintenance Ltd | Administrative & support | 2021 |
| JSS Property Group Ltd | Real estate | 2024 |
| JTB Ltd | Real estate | 2018 |
| JTS Plumbing & Heating (Cheshunt) Limited | Construction | 2017 |
| JTS Property Services (London) Limited | Construction | 2024 |
| Jude IT Limited | Professional & scientific | 2013 |
| Judejames Limited | Hospitality | 2020 |
| Judith HAY Limited | Professional & scientific | 2018 |