| JM Valuation Group Ltd | Real estate | 2018 |
| JMA Assets Limited | Real estate | 2025 |
| Jmac Design Ltd | Construction | 2022 |
| JMB Licence Limited | Administrative & support | 2016 |
| JMC Waste Disposal Limited | Wholesale & retail | 2011 |
| Jmhl Properties Ltd | Real estate | 2020 |
| JMR Forgemaster Ltd | Manufacturing | 2004 |
| JMT Consults Ltd | Professional & scientific | 2024 |
| JNC Limited | Professional & scientific | 2022 |
| JNL Delivery Services Limited | Transport & logistics | 2006 |
| JNS Chauffeur Services Limited | Other services | 2023 |
| JO Developers Limited | Real estate | 2025 |
| JO Garnelas Recruitment Limited | Administrative & support | 2015 |
| JO Salinger Hair Ltd | Other services | 2025 |
| JO Tutoring Limited | Education | 2020 |
| JOAOTRANS2022 Ltd | Transport & logistics | 2022 |
| Joceline Ltd | Wholesale & retail | 2018 |
| Jodie Fundraising Limited | Administrative & support | 2023 |
| JOE Birdsey Ltd | Arts & recreation | 2018 |
| JOE Block Limited | Construction | 2014 |
| Joel Anderson Photography Limited | Professional & scientific | 2003 |
| John a. Hart (Carpet) Limited | Wholesale & retail | 1982 |
| John A.Taylor & Sons Limited | Wholesale & retail | 1955 |
| John Boyle Computer Services Limited | Information & communication | 2002 |
| John C Construction Limited | Construction | 2018 |
| John E. Griggs & Sons Limited | Construction | 1972 |
| John Farrell & Associates Limited | Administrative & support | 2009 |
| John Reddington Ltd | Agriculture & fishing | 2023 |
| Johns Itec Services Ltd | Construction | 2022 |
| Johnson R Electricals Ltd | Construction | 2021 |
| Johnstone Care Centre Ltd | Health & social care | 2018 |
| Joiners Financial Ltd | Administrative & support | 2019 |
| Joiners of Saul Limited | Construction | 2013 |
| Joint Care London Limited | Health & social care | 2020 |
| Joint Effort Productions Ltd | Information & communication | 2014 |
| Joint Holdings Limited | Financial services | 2015 |
| Jointpartners Limited | Health & social care | 2018 |
| Jojam Limited | Real estate | 2023 |
| Jojaru Ltd | Other services | 2018 |
| Jolena Ltd | Professional & scientific | 2016 |
| JON B Hair Limited | Other services | 2015 |
| JON Davids Construction Ltd | Construction | 2015 |
| JON Flynn Marketing Limited | Administrative & support | 2012 |
| JON Howard Construction Ltd. | Construction | 2019 |
| Jonamaytime Ltd | Professional & scientific | 2024 |
| Jonathan Mason Ltd | Health & social care | 2010 |
| Jonathan Wilson Productions Ltd | Information & communication | 2014 |
| Jones Signs (Holdings) Ltd | Professional & scientific | 2013 |
| Jonny Huntington Skiing Ltd | Arts & recreation | 2023 |
| Jonny Storey Limited | Professional & scientific | 2003 |
| Jonray Film Construction Limited | Information & communication | 1994 |
| Jormarnie Capital Limited | Administrative & support | 2019 |
| Josal Property Development Limited | Real estate | 2019 |
| Josal Property Limited | Extraterritorial | 2015 |
| Josephine Michaels Estates Limited | Real estate | 2024 |
| Joss Construction Ltd | Construction | 2016 |
| Joysleep Holdings Limited | Real estate | 2008 |
| JP Bookkeeping Services Limited | Professional & scientific | 2014 |
| JP Lighting Ltd | Administrative & support | 2021 |
| JP Procurement Solutions Limited | Professional & scientific | 2023 |
| JPA Estates UK Limited | Real estate | 2019 |
| JPI Technologies Ltd | Manufacturing | 2018 |
| JPM1 Ltd | Real estate | 2025 |
| JPM2 Ltd | Professional & scientific | 2025 |
| Jptaylor Construction Ltd | Information & communication | 2022 |
| Jqbs TM Ltd | Transport & logistics | 2020 |
| JR Props & Carpentry Ltd | Construction | 2024 |
| JRL (DM) Limited | Construction | 2024 |
| JRL Access Limited | Construction | 2018 |
| JRL Brick-Slip Systems Ltd | Manufacturing | 2018 |
| JRL Civil Engineering Limited | Construction | 2009 |
| JRL Construction Management Limited | Financial services | 2021 |
| JRL Demolition Limited | Construction | 2016 |
| JRL Drylining Limited | Construction | 2010 |
| JRL Environmental Limited | Construction | 2013 |
| JRL GH Facades Limited | Construction | 2021 |
| JRL Group (Ireland) Limited | Financial services | 2016 |
| JRL Group Holdings Limited | Financial services | 2009 |
| JRL Group Limited | Financial services | 2008 |
| JRL Modular Ltd | Construction | 2021 |
| JRL Plant & Services Ltd. | Extraterritorial | 2002 |
| JRL Plant and Logistics Limited | Administrative & support | 2003 |
| JRL Property (2) Ltd | Real estate | 2021 |
| JRL Property (4) Ltd | Real estate | 2021 |
| JRL Property (5) Ltd | Real estate | 2021 |
| JRL Property (6) Ltd | Real estate | 2021 |
| JRL Property (Biggleswade) Limited | Real estate | 2014 |
| JRL Property (Camley Street) Limited | Real estate | 2016 |
| JRL Property (Carlton Works) Limited | Real estate | 2021 |
| JRL Property (Castle Street) Holdings Limited | Financial services | 2025 |
| JRL Property (Castle Street) Ltd | Construction | 2015 |
| JRL Property (Castle Street) Opco Limited | Real estate | 2025 |
| JRL Property (Colwick) Limited | Real estate | 2016 |
| JRL Property (Coventry) Limited | Real estate | 2017 |
| JRL Property (Cumberland Street) Ltd | Construction | 2020 |
| JRL Property (Euston Road) Limited | Construction | 2018 |
| JRL Property (Frederick ST) Ltd | Real estate | 2021 |
| JRL Property (Peterborough) Limited | Real estate | 2016 |
| JRL Property (Portadown) Ltd | Real estate | 2021 |
| JRL Property (Putney) Limited | Real estate | 2016 |