| JK Nine Two Limited | Professional & scientific | 1996 |
| JKC Limited | Other services | 2015 |
| JKD Accountants Limited | Professional & scientific | 2022 |
| JKD Investment Holdings Ltd | Financial services | 2021 |
| JKD Property Investments Limited | Real estate | 2019 |
| JKL Moseley Limited | Real estate | 2013 |
| JL Adventures Ltd | Wholesale & retail | 2025 |
| JL Photographic Ltd | Wholesale & retail | 2020 |
| JLB Capital Holdings Ltd | Financial services | 2025 |
| JLF Limited | Real estate | 2024 |
| JLK Services Ltd | Manufacturing | 2020 |
| JLM Negocios Limited | Wholesale & retail | 2025 |
| JLM Technical Ltd | Information & communication | 2026 |
| JLP Limited | Other services | 2018 |
| JM - Logistic Services Ltd | Wholesale & retail | 2014 |
| JM Bookkeeping Ltd | Professional & scientific | 2023 |
| JM Healey Properties Ltd | Real estate | 2024 |
| JM Rent Wise Management Ltd | Real estate | 2023 |
| JM Transformations Ltd | Other services | 2024 |
| Jmarc Holdings Ltd | Wholesale & retail | 2025 |
| Jmatek UK Limited | Wholesale & retail | 2017 |
| JMB Developments Yorkshire Ltd | Households | 2025 |
| JMC Homes (Dorset) Ltd | Real estate | 2023 |
| JMC Services (Bournemouth) Limited | Administrative & support | 2018 |
| JMD Impact Ltd | Professional & scientific | 2024 |
| Jmgsales Ltd | Wholesale & retail | 2024 |
| Jmj-Media Ltd | Information & communication | 2017 |
| Jmsd Publishing Limited | Manufacturing | 2014 |
| Jmts Construction Ltd | Construction | 2022 |
| Jmtv Holding Ltd | Financial services | 2025 |
| Jmtv Investments Limited | Financial services | 2022 |
| JNF Consultancy Services Limited | Professional & scientific | 2022 |
| JNM Trading Limited | Wholesale & retail | 2018 |
| JNO Services Ltd | Health & social care | 2025 |
| JNR Innovations Ltd | Manufacturing | 2025 |
| JNX Digital Limited | Wholesale & retail | 2025 |
| JO Mount and Associates Limited | Health & social care | 2017 |
| Joan Marie Publishing Limited | Information & communication | 2020 |
| JOB Angels Ltd | Wholesale & retail | 2021 |
| JOB Done Express Ltd | Transport & logistics | 2021 |
| JOE CAN DO Limited | Information & communication | 2017 |
| JOE Legge Building Ltd | Construction | 2024 |
| Joelle Kinia Limited | Information & communication | 2022 |
| John Comber Limited | Professional & scientific | 2012 |
| John Cribb & Sons Ltd. | Wholesale & retail | 1981 |
| John Galt Ltd | Financial services | 2014 |
| John K Services Limited | Other services | 2021 |
| John Morris & Associates Limited | Information & communication | 2002 |
| John Pipe Limited | Manufacturing | 1961 |
| Johnnie Longden Limited | Wholesale & retail | 2003 |
| Johnsher Limited | Wholesale & retail | 2018 |
| Johnson & Jones Decorators Ltd | Construction | 2018 |
| Johnson Baker and Company Limited | Construction | 1934 |
| Johnson Finishing Ltd | Construction | 2025 |
| Johnson L Limited | Wholesale & retail | 2016 |
| Johnson Wells Limited | Real estate | 2010 |
| Johnsonmarinespecialists Ltd | Manufacturing | 2024 |
| Johnsons Renovations Ltd | Construction | 2022 |
| Joiskka Ltd | Information & communication | 2025 |
| Jokon (GB) Limited | Wholesale & retail | 1987 |
| Joleon Consulting Ltd | Manufacturing | 2022 |
| Joleon Property Limited | Real estate | 2019 |
| Jolliffe Properties Ltd | Real estate | 1999 |
| Jolly Country Park Ltd | Hospitality | 2022 |
| Jolp Limited | Professional & scientific | 2021 |
| Jolp Western Limited | Professional & scientific | 2026 |
| Jolski Limited | Information & communication | 2013 |
| JON Exton Limited | Financial services | 2007 |
| JON Holt Associates Limited | Professional & scientific | 2012 |
| JON Magazine Limited | Information & communication | 2015 |
| JON Mitchell Property Services Ltd | Administrative & support | 2010 |
| JON Williams Ltd | Extraterritorial | 2023 |
| Jonachar Limited | Administrative & support | 2021 |
| Jonathan Mcharg Consulting Ltd | Information & communication | 2025 |
| Jonathan Morris Construction Limited | Construction | 2004 |
| Jondan IP Limited | Administrative & support | 2015 |
| Jondan Limited | Administrative & support | 2021 |
| Jondan Projects Limited | Construction | 2020 |
| Jonny's Sister Limited | Wholesale & retail | 2014 |
| Joomla Day UK Ltd | Other services | 2026 |
| Jordan Future Limited | Real estate | 1995 |
| Joresp Trading Ltd | Information & communication | 2021 |
| Jorgkind Limited | Real estate | 2021 |
| Joscelyne Building Contractors Ltd | Extraterritorial | 2022 |
| Joscelyne Property Maintenance Ltd | Construction | 2022 |
| Joseph Conrad JC Ltd | Wholesale & retail | 2017 |
| Joshewer Limited | Construction | 1973 |
| Joshua Tyler Development Limited | Information & communication | 2023 |
| Jotz Limited | Real estate | 2020 |
| Journey Angels Limited | Administrative & support | 2024 |
| Journey Park Homes and Lodges Ltd | Manufacturing | 2022 |
| Journeyright Limited | Transport & logistics | 2020 |
| Jovs Business Ltd | Wholesale & retail | 2025 |
| Joy Coaching and Consulting Ltd | Professional & scientific | 2025 |
| Joy Hing Chinese Takeaway Ltd | Hospitality | 2026 |
| Joy Zone Ltd | Wholesale & retail | 2025 |
| Joycaffe Ltd | Wholesale & retail | 2020 |
| Joyful Ltd | Hospitality | 2018 |
| Joyliving Property Ltd | Real estate | 2026 |
| Joymeta Limited | Information & communication | 2021 |