| Jackson Commercial Services Ltd | Wholesale & retail | 2025 |
| Jackson Equestrian Limited | Real estate | 2004 |
| Jacobs Court Management Company Limited | Households | 2002 |
| Jacqueline Court Management Company Limited | Households | 2005 |
| JAE Whittingham Ltd | Agriculture & fishing | 2022 |
| JAG of ALL Trades Limited | Construction | 2003 |
| Jagatjit Ltd | Hospitality | 2024 |
| Jake Peter Lawley Ltd | Households | 2024 |
| JAL Built Environment Ltd | Professional & scientific | 2021 |
| James Corfield Contracting Ltd | Other services | 2019 |
| James Court (Woolton) Management Company Limited | Households | 1981 |
| James Griffiths Electrical Services Ltd | Construction | 2021 |
| James Holyoak & Parker Limited | Professional & scientific | 2005 |
| James Lescott Bespoke Interiors Limited | Manufacturing | 2022 |
| James Tudor Brickwork Limited | Construction | 2015 |
| Jamie Challinor Insurance Solutions Ltd | Financial services | 2016 |
| Jamily Automation Ltd | Manufacturing | 2019 |
| Janet Hollis H.R. Consultancy Limited | Administrative & support | 2015 |
| Japan Square Limited | Wholesale & retail | 2020 |
| Jarris Properties Limited | Real estate | 2024 |
| Jarvis Metals Limited | Water & waste | 2009 |
| Jarvis Property Holdings Limited | Financial services | 2025 |
| Jarvis Scaffolding Limited | Construction | 2009 |
| Jasman Global Ltd | Real estate | 2019 |
| Jasmine Gardens (Residential Management Company) Limited | Real estate | 2014 |
| Jason Bradley (Shrewsbury) Limited | Wholesale & retail | 2018 |
| Jason Evans Plastering Limited | Construction | 2013 |
| Jassel Properties Ltd | Real estate | 2004 |
| Jaybug Limited | Arts & recreation | 2014 |
| Jayroc Ltd | Agriculture & fishing | 2019 |
| JB Carpentry (Shrewsbury) Limited | Manufacturing | 2018 |
| JB Property Ventures Ltd | Real estate | 2024 |
| JB Solar Installation Limited | Construction | 2026 |
| JB31COACHING Ltd | Arts & recreation | 2022 |
| Jbrits Ltd | Agriculture & fishing | 2025 |
| Jbsealants Ltd | Construction | 2020 |
| JC Automotive Ltd | Wholesale & retail | 2026 |
| JC Industrial Company Limited | Wholesale & retail | 2018 |
| JCK Offshore Ltd | Construction | 2013 |
| JD Mason Limited | Information & communication | 2021 |
| JD Modo Ltd | Construction | 2012 |
| JD Tree Services Ltd | Agriculture & fishing | 2014 |
| JDC Maintenance Limited | Construction | 2005 |
| JDC Property Investment Ltd | Real estate | 2023 |
| Jdent Ltd | Health & social care | 2018 |
| JDI Sales Ltd | Wholesale & retail | 2025 |
| JDN Products Ltd | Wholesale & retail | 2019 |
| Jdrc Control Systems Limited | Wholesale & retail | 2025 |
| JDS Carpentry and Developments Limited | Construction | 2020 |
| JDT Interiors Ltd | Wholesale & retail | 2025 |
| JDW Strategy Ltd | Professional & scientific | 2025 |
| Jear Properties Ltd | Real estate | 2016 |
| Jefod Limited | Health & social care | 2026 |
| JEG Management Limited | Professional & scientific | 2022 |
| JEH Investments Ltd | Construction | 2025 |
| Jekolia Limited | Real estate | 2018 |
| JEL Management Consultancy Limited | Professional & scientific | 2014 |
| JEM Finance Ltd | Financial services | 2007 |
| Jemco Holdings Limited | Financial services | 2025 |
| Jemco VPA Limited | Wholesale & retail | 2025 |
| Jenerate Solutions Ltd | Information & communication | 2025 |
| Jenkins Garages (Wales) Limited | Wholesale & retail | 2007 |
| Jenkinson Management Limited | Professional & scientific | 2024 |
| Jenko’S Automotive's Ltd | Wholesale & retail | 2025 |
| Jenna Blair Yoga Ltd | Arts & recreation | 2024 |
| Jenny Blackhurst Books Limited | Arts & recreation | 2013 |
| Jenny’S Nails & Spa Ltd | Other services | 2025 |
| Jesent Limited | Administrative & support | 2019 |
| Jessica Wake Limited | Health & social care | 2015 |
| Jessica's Bridal and Evening Wear Limited | Wholesale & retail | 2015 |
| JET KIN Hand Car Wash & Valeting Servises Ltd | Wholesale & retail | 2015 |
| Jethro Hill Limited | Real estate | 2013 |
| JF Drainage Limited | Extraterritorial | 2014 |
| JGM Fletcher Ltd | Professional & scientific | 2015 |
| JH C5I Consultancy Ltd | Information & communication | 2024 |
| JH Care Consultancy Services Ltd | Professional & scientific | 2025 |
| JH Coaching and Advisory Limited | Professional & scientific | 2025 |
| JHL Property Management Limited | Real estate | 2024 |
| Jigsaw Marquees Ltd | Wholesale & retail | 2014 |
| JIM Dorricott Construction Ltd | Construction | 2007 |
| JIM Pugh Limited | Agriculture & fishing | 2016 |
| Jinfa Limited | Financial services | 2025 |
| Jingsh London Office Limited | Professional & scientific | 2021 |
| JJ Distribution Ltd | Wholesale & retail | 2023 |
| JJ Football Ltd | Education | 2025 |
| JJB (Business) Ltd | Administrative & support | 2013 |
| Jjlh Limited | Wholesale & retail | 2007 |
| JK Coatings Limited | Professional & scientific | 2014 |
| JL UK Freelance Ltd | Agriculture & fishing | 2016 |
| JL UK Property Ltd | Real estate | 2026 |
| JLB Agencies Limited | Wholesale & retail | 2014 |
| Jlfisher Ltd | Real estate | 2021 |
| JLK Haulage Solutions Ltd | Administrative & support | 2018 |
| JLM Medical Limited | Health & social care | 2019 |
| JLP Roofing Contractors Limited | Construction | 2023 |
| JLW Distribution Limited | Wholesale & retail | 2023 |
| JMA Construction Services Ltd | Construction | 2024 |
| JMC Hospitality Group Ltd | Hospitality | 2025 |
| Jmrb Property Limited | Real estate | 2024 |
| Jneop Ltd | Education | 2025 |