| Jennifer Amani Limited | Manufacturing | 2025 |
| Jenny Luxe Nails Ltd | Other services | 2026 |
| Jenny's Services Limited | Health & social care | 2025 |
| Jennz Hair Lounge Ltd | Other services | 2024 |
| Jeppesen Court (Stanwell) Management Company Limited | Households | 2003 |
| Jerema Ltd | Real estate | 2022 |
| Jeremiah Construction Limited | Construction | 2019 |
| Jeremy Colson Bathrooms Limited | Construction | 2014 |
| Jeremy Leach Research Limited | Professional & scientific | 2008 |
| Jerk Joint Catering Services Ltd | Hospitality | 2017 |
| Jerk Valley Limited | Hospitality | 2026 |
| Jerk World Limited | Manufacturing | 2025 |
| Jerk Yard London Ltd | Hospitality | 2026 |
| JERKMAICAN1 Ltd | Hospitality | 2015 |
| Jero Ejoh Ltd | Health & social care | 2014 |
| Jerona Limited | Professional & scientific | 2006 |
| Jersey Fields (Middlewich) Management Company Limited | Households | 2012 |
| Jess & MAX Private Ltd | Hospitality | 2023 |
| Jessdavid Ltd | Hospitality | 2025 |
| Jesse SN Limited | Other services | 2026 |
| Jessie's Kitchen Ltd | Hospitality | 2023 |
| Jester Hospitality Ltd | Hospitality | 2023 |
| Jesu-Segunlondon Limited | Wholesale & retail | 2015 |
| Jesukorede Ltd | Information & communication | 2025 |
| Jesus in Action UK Limited | Professional & scientific | 2018 |
| JET Quick Couriers Ltd | Transport & logistics | 2025 |
| Jetsim UK Ltd | Wholesale & retail | 2025 |
| Jetwo Fuels Ltd | Manufacturing | 2026 |
| Jeux DE Couleur Limited | Information & communication | 2002 |
| Jeva Limited | Extraterritorial | 2011 |
| Jezengineering Limited | Administrative & support | 2025 |
| JF Drainage Solutions Ltd | Construction | 2021 |
| JF Renovations Ltd | Other services | 2021 |
| JG & Associates | Professional & scientific | 2018 |
| JG Williams Holding Group Limited | Financial services | 2026 |
| JGB Intl Ltd | Information & communication | 2024 |
| JGN Recruitment Limited | Administrative & support | 2019 |
| Jgns Recruitment Limited | Real estate | 2023 |
| Jgsg Retail Limited | Wholesale & retail | 2018 |
| JH & T Trading Limited | Wholesale & retail | 2012 |
| JH Autos Limited | Wholesale & retail | 2017 |
| JH Group Food & Wine Ltd | Wholesale & retail | 2025 |
| JHK Convenience Limited | Wholesale & retail | 2023 |
| JHM Advisory Services Ltd | Professional & scientific | 2022 |
| JHP Traders Limited | Administrative & support | 2025 |
| JHS Holdings Limited | Financial services | 2019 |
| JHU Cleans Ltd | Administrative & support | 2024 |
| Jibonshoily Apparel Accessories and Educational Consultation Private Limited | Wholesale & retail | 2026 |
| Jiconi London Transport Limited | Transport & logistics | 2026 |
| Jido Services Ltd | Transport & logistics | 2018 |
| Jigum Ltd | Professional & scientific | 2021 |
| Jijo Ltd | Manufacturing | 2008 |
| Jill and Lizzy's Building Company Limited | Construction | 2015 |
| JIM Guest Design Limited | Professional & scientific | 2012 |
| Jimlas Sourcing Property Limited | Real estate | 2023 |
| Jinhui Trading Ltd | Wholesale & retail | 2025 |
| Jinni Limited | Health & social care | 2025 |
| Jinrong Ltd | Wholesale & retail | 2025 |
| Jireh Avodah Consulting Ltd | Education | 2023 |
| Jireh Hospitality Services Ltd | Administrative & support | 2024 |
| Jiro Hotels Ltd | Hospitality | 2026 |
| Jishico Limited | Professional & scientific | 2008 |
| JIW Health Ltd | Health & social care | 2019 |
| JJ Build & Development Ltd | Construction | 2021 |
| JJ Chase Development Ltd. | Construction | 2015 |
| JJ Employment Services Ltd | Transport & logistics | 2017 |
| JJ Leisure Ltd | Hospitality | 2015 |
| JJ Properties and Services Ltd | Real estate | 2025 |
| JJ Rebar Limited | Other services | 2018 |
| JJ Service London Ltd | Administrative & support | 2022 |
| JJ Services and Resource Management Ltd | Transport & logistics | 2013 |
| JJ Sons Building Services Limited | Construction | 2018 |
| JJ Splice Solution Ltd | Information & communication | 2022 |
| JJB Housing Ltd | Real estate | 2023 |
| JJD Security Systems Limited | Administrative & support | 2018 |
| JJK Financial Services Ltd | Financial services | 2023 |
| JK & TJ Property Group Limited | Real estate | 2025 |
| JK Building London Ltd | Construction | 2011 |
| JK Carpentry & Building Ltd | Manufacturing | 2019 |
| JK Food Store Ltd | Wholesale & retail | 2025 |
| JK Foods PVT Ltd | Wholesale & retail | 2014 |
| JK Market Research Ltd | Professional & scientific | 2016 |
| JK Pro Builders Ltd | Construction | 2025 |
| JK Shippers Ltd | Transport & logistics | 2024 |
| JK Supermarket Limited | Wholesale & retail | 2019 |
| JK Systems Limited | Information & communication | 2013 |
| Jkasule Ltd | Manufacturing | 2025 |
| Jkis Construction Ltd | Construction | 2025 |
| Jklr Limited | Construction | 2025 |
| JKP Restaurants Limited | Hospitality | 2016 |
| JKS Stuart Holdings Limited | Financial services | 2025 |
| JL Global Transit Ltd | Transport & logistics | 2025 |
| JL London Limited | Other services | 2018 |
| JLB Childcare Limited | Health & social care | 2010 |
| JLB Properties Surrey Limited | Real estate | 2020 |
| JLH Contractors Ltd | Construction | 2019 |
| JLM Produce Limited | Wholesale & retail | 2005 |
| JLS Interiors Ltd | Professional & scientific | 2018 |
| JM Care Staffing Ltd | Health & social care | 2020 |
| JM Establishment Ltd | Real estate | 2023 |