| Jacob Coupe Ltd | Arts & recreation | 2017 |
| Jacob Oliver Ltd | Construction | 2021 |
| JACOB123 Limited | Wholesale & retail | 2011 |
| Jacobs & Ferguson Ltd | Real estate | 2025 |
| Jacoda Properties Limited | Construction | 2020 |
| Jacqueline Butters Ltd | Information & communication | 2025 |
| Jacqueline Rosemary Thomas Ltd | Extraterritorial | 2024 |
| Jacran Limited | Health & social care | 2014 |
| Jacs International Ltd | Transport & logistics | 2024 |
| Jada Services Limited | Health & social care | 2022 |
| Jaddoo Healthcare Ltd | Health & social care | 2022 |
| Jade Barnett Ltd | Administrative & support | 2024 |
| Jade Healthcare Services Ltd | Administrative & support | 2016 |
| Jade Topco Holding Limited | Financial services | 2026 |
| Jade Traore Ltd | Health & social care | 2024 |
| Jade Wealth Management Limited | Financial services | 2025 |
| Jadeda Co Ltd | Wholesale & retail | 2026 |
| Jadefine Limited | Real estate | 1986 |
| Jadell Holdings Ltd | Financial services | 2020 |
| Jadobry Limited | Financial services | 2018 |
| Jadun Locums Limited | Health & social care | 2014 |
| JAE Engineering Consultancy Limited | Professional & scientific | 2020 |
| JAF & Sons Ltd | Financial services | 2022 |
| Jafaru ABU Limited | Health & social care | 2010 |
| Jafral UK Ltd | Manufacturing | 2026 |
| JAG Bidco Limited | Financial services | 2019 |
| JAG Capital Group Limited | Financial services | 2020 |
| JAG Construction (Midlands) Limited | Construction | 2016 |
| JAG Ents Limited | Information & communication | 2005 |
| JAG Homes Group Limited | Construction | 2024 |
| JAG Platforms Limited | Information & communication | 2024 |
| JAG Properties (Midlands) Limited | Real estate | 2018 |
| JAG Real Estate Limited | Real estate | 2020 |
| JAG Retail Limited | Administrative & support | 2021 |
| JAG Topco Limited | Financial services | 2019 |
| Jagaero Ltd | Manufacturing | 2024 |
| Jagannath Solutions Ltd | Real estate | 2022 |
| Jagdish Patel Photography Ltd | Professional & scientific | 2007 |
| Jager Shoots Ltd | Professional & scientific | 2023 |
| Jagger GP & JP Investments Ltd | Other services | 2018 |
| Jago Europe Ltd | Wholesale & retail | 2004 |
| Jagr Limited | Construction | 2016 |
| Jaguar Consultancy Services Ltd | Professional & scientific | 2016 |
| Jagz Decor Ltd | Hospitality | 2024 |
| Jagz Trading Limited | Professional & scientific | 2016 |
| JAH Driving School Ltd | Education | 2025 |
| Jahanzaib Auto Solutions Ltd | Wholesale & retail | 2026 |
| Jahmad Ltd | Information & communication | 2006 |
| JAI Ambay Limited | Transport & logistics | 2007 |
| Jai'Rah Stores Limited | Wholesale & retail | 2024 |
| Jaihanuman Caterings Ltd | Hospitality | 2026 |
| Jail Mail Limited | Information & communication | 2014 |
| Jaime DE Castro Torres Limited | Health & social care | 2014 |
| Jaime Martin Ltd | Arts & recreation | 2012 |
| Jairos Healthcare Services Ltd | Health & social care | 2018 |
| Jaishapal Investments Ltd | Construction | 2011 |
| Jajawi & Asker FIC Limited | Financial services | 2026 |
| Jajawi & Asker Investment Ltd | Real estate | 2026 |
| Jajawi & Asker Ltd | Real estate | 2015 |
| Jajawi Ltd | Real estate | 2011 |
| Jake Enterprises Limited | Financial services | 2020 |
| Jake Group Limited | Financial services | 2020 |
| Jake Smith Garden and Landscapes Limited | Administrative & support | 2025 |
| Jake Spencer Composite Solutions Limited | Professional & scientific | 2021 |
| Jake-Komura Partnership (UK) Limited | Financial services | 2020 |
| Jake-Komura Partnership Limited | Financial services | 2012 |
| Jakes Breaks Ltd | Arts & recreation | 2024 |
| Jakub Construction Limited | Construction | 2023 |
| Jakub Florys Ltd | Transport & logistics | 2018 |
| Jakub Hnatko Transport Limited | Transport & logistics | 2019 |
| JAL Property Services Limited | Real estate | 2021 |
| Jale House Limited | Real estate | 2025 |
| Jalinarl Ltd | Health & social care | 2019 |
| Jalland & Co.Limited | Real estate | 1896 |
| Jallons Ltd. | Other services | 2025 |
| JAM Games Limited | Information & communication | 2025 |
| JAM JAR Building and Property Services Limited | Real estate | 2016 |
| JAM Management Limited | Administrative & support | 2014 |
| JAM Print Services Ltd | Professional & scientific | 2026 |
| Jam's Transport Ltd | Transport & logistics | 2023 |
| Jam-Product Forge Ltd | Information & communication | 2022 |
| JAM37 Ltd | Professional & scientific | 2022 |
| Jama PS Limited | Health & social care | 2016 |
| Jamaa'Tu Ahli Llahi Nottingham,Uk. Ltd. | Other services | 2014 |
| Jamaal Raoof Ltd | Arts & recreation | 2024 |
| Jamay Consulting Limited | Information & communication | 2006 |
| Jambray Ltd | Information & communication | 2005 |
| Jambru Ltd | Transport & logistics | 2012 |
| James & Thomas Limited | Extraterritorial | 1958 |
| James Arnia Photography Limited | Arts & recreation | 2008 |
| James Blowers Limited | Financial services | 2013 |
| James Booth Limited | Other services | 2002 |
| James Brian Tools Limited | Wholesale & retail | 2025 |
| James Dames Limited | Education | 2024 |
| James Duncan Investments Limited | Financial services | 1950 |
| James FRY Ltd | Financial services | 2012 |
| James Grace Properties Ltd | Real estate | 2022 |
| James Hale Limited | Health & social care | 2014 |
| James Harrison Business Solutions Limited | Professional & scientific | 2008 |
| James Hawes & Goodchild Limited | Extraterritorial | 1947 |