| Jetcar International Limited | Wholesale & retail | 2025 |
| Jethe Limited | Real estate | 2025 |
| Jeti Windows Ltd | Construction | 2022 |
| Jetreps Ltd | Professional & scientific | 2022 |
| Jetstream Financial Services Ltd | Professional & scientific | 2022 |
| JEU DE Paume Limited | Extraterritorial | 2024 |
| Jewel Beauty & Head Spa Limited | Other services | 2026 |
| Jewel Leisure Limited | Arts & recreation | 2023 |
| Jewels Drylining Ltd | Construction | 2023 |
| JEZ Junior Media Ltd | Information & communication | 2026 |
| Jezlag Limited | Information & communication | 2026 |
| Jfaat Ltd | Professional & scientific | 2025 |
| Jgal Developments Ltd | Construction | 2020 |
| JGM Fitters Limited | Construction | 2016 |
| JH Asset Group Ltd | Transport & logistics | 2026 |
| JH Drylining Ltd | Construction | 2012 |
| JH Pro Clean Ltd | Administrative & support | 2025 |
| Jhgd Heating Limited | Construction | 2015 |
| JIB Estates Ltd | Construction | 2025 |
| Jibven Trading Ltd | Wholesale & retail | 2010 |
| Jiggle Ltd | Wholesale & retail | 2021 |
| Jigsaw Assets Limited | Construction | 2017 |
| JIJ Group Ltd. | Construction | 2016 |
| JIM Jackson Ltd. | Professional & scientific | 2021 |
| JIM Wicks Properties Ltd | Real estate | 2025 |
| Jimt Limited | Professional & scientific | 2017 |
| Jingadoru Ltd | Transport & logistics | 2021 |
| Jiwani Consultancy Ltd | Information & communication | 2011 |
| JJ Nerja Rentals Limited | Real estate | 2024 |
| JJ Search Limited | Professional & scientific | 2017 |
| JJ Vendors Ltd | Wholesale & retail | 2025 |
| JJJ Prestige Care Limited | Health & social care | 2020 |
| Jjrquo Limited | Professional & scientific | 2021 |
| JJS Smokeshack Limited | Hospitality | 2025 |
| JJT Services Ltd | Professional & scientific | 2022 |
| JJV Lettings Ltd | Real estate | 2019 |
| JK Link Limited | Wholesale & retail | 2024 |
| JKL Projects Limited | Construction | 2007 |
| JL Convenience Shop Ltd | Wholesale & retail | 2020 |
| JL Fashion Limited | Wholesale & retail | 2014 |
| JL Megran Consulting Ltd | Administrative & support | 2017 |
| JLC Investments Limited | Real estate | 2019 |
| Jlds Consultancy Limited | Administrative & support | 2019 |
| JLF Hair Salon Ltd | Other services | 2020 |
| JLM Lofts & Extensions Ltd | Real estate | 2025 |
| JLM Maintenance Ltd | Construction | 2021 |
| Jlnegus Ltd | Wholesale & retail | 2026 |
| JLR Market Insights Ltd | Professional & scientific | 2025 |
| JLW@25 Limited | Construction | 2020 |
| JLX Consultants Limited | Information & communication | 2012 |
| JM Builders Group Ltd | Construction | 2021 |
| JM Commissioning & Water Treatment Ltd | Water & waste | 2022 |
| JM Prop Ltd | Real estate | 2015 |
| Jm-Re Real Estate Advisors Ltd | Real estate | 2022 |
| JMB Consulting (Pleshey) Ltd | Professional & scientific | 2012 |
| JMC Mechanical Services Ltd | Professional & scientific | 2011 |
| Jmcj Ltd | Construction | 2024 |
| Jmcj Property Ltd | Real estate | 2025 |
| JMD Resources Limited | Information & communication | 2018 |
| JML Designers Limited | Manufacturing | 2009 |
| JML Restaurant Group Ltd | Hospitality | 2019 |
| JMR Recruitment Services Ltd | Administrative & support | 2018 |
| Jmvcs Ltd | Information & communication | 2021 |
| Jnep Limited | Real estate | 2017 |
| JNL Consulting Limited | Real estate | 2025 |
| JNL Investments Limited | Construction | 2021 |
| Jobcreate Ltd | Administrative & support | 2024 |
| Jobin Jacob Ltd | Financial services | 2024 |
| Jobsnetwork Consulting (GB) Ltd | Administrative & support | 2021 |
| Jobson Media Limited | Information & communication | 2002 |
| JOE Gosling Music Ltd | Arts & recreation | 2022 |
| JOE4LIFE Ltd | Hospitality | 2024 |
| Joebe UK Ltd | Wholesale & retail | 2020 |
| Joemackrail Ltd | Construction | 2022 |
| Joes Property Ltd | Real estate | 2020 |
| Jogsoft Limited | Information & communication | 2003 |
| John Ballentyne Associates Limited | Health & social care | 2009 |
| John Charles Butchers Ltd | Extraterritorial | 2024 |
| John Delander Ltd | Health & social care | 2021 |
| John Finch Partnership Limited | Professional & scientific | 2012 |
| John Ford Group Ltd | Construction | 2009 |
| John Man’N Vans Ltd | Transport & logistics | 2026 |
| John Mclaren Agriculture Ltd | Agriculture & fishing | 2011 |
| John Morley Specialist Waterproofing Limited | Construction | 2003 |
| John Rush Electrical Limited | Construction | 2020 |
| John Stacey Limited | Agriculture & fishing | 2012 |
| John Thorogood Fine Woodworking Limited | Manufacturing | 2015 |
| John White PM Ltd | Information & communication | 2012 |
| John's Capital Development Limited | Construction | 2012 |
| Johnia Estates Ltd | Real estate | 2026 |
| Johnman Partnership Limited | Professional & scientific | 2023 |
| Johnson Technical Security Ltd | Information & communication | 2018 |
| Johnson Technical Systems Ltd | Information & communication | 2004 |
| Johnsons Auto Electrics Limited | Wholesale & retail | 2006 |
| Johnstruct Ltd | Construction | 2009 |
| Jokaka Limited | Transport & logistics | 2014 |
| Jolyon Group Ltd | Professional & scientific | 2026 |
| JOM Properties Ltd | Real estate | 2026 |
| JON Bassett Ltd | Construction | 2014 |
| JON Hollis PUB Company Ltd | Hospitality | 2025 |