| Jamarch Limited | Professional & scientific | 2024 |
| James Bros Developments Ltd | Construction | 2023 |
| James Dean Creative Landscapes Ltd. | Administrative & support | 2002 |
| James Gray Holdings Limited | Extraterritorial | 2022 |
| James Kersey Ltd | Health & social care | 2014 |
| James M Consulting Limited | Information & communication | 2016 |
| James Powell Software Development Ltd | Information & communication | 2021 |
| James Surridge Brand Performance Limited | Professional & scientific | 2026 |
| Jamk Services Limited | Professional & scientific | 2018 |
| Jamm Logistics Ltd | Transport & logistics | 2025 |
| Jampot Investments (West) Ltd | Hospitality | 2023 |
| Janeway and Wildman Limited | Manufacturing | 2022 |
| Japanese Knotweed Limited | Professional & scientific | 2010 |
| Jara Farm (Property) Ltd | Real estate | 2004 |
| Jarrold Media Ltd | Information & communication | 2011 |
| Jasmine Thai Massage & Spa Ringwood Limited | Other services | 2024 |
| Javis Limited | Wholesale & retail | 2022 |
| JAW Studios Limited | Professional & scientific | 2026 |
| Jay-N Enterprise Ltd | Administrative & support | 2025 |
| Jaybirds Painting and Decorating Services Ltd | Administrative & support | 2023 |
| Jaydowe Limited | Energy | 2021 |
| Jaymax Electrical Engineers Limited | Manufacturing | 2006 |
| JB Change Ltd | Professional & scientific | 2021 |
| JB Design Services Ltd | Information & communication | 2022 |
| JBK Accounting Ltd | Professional & scientific | 2024 |
| JBM Consulting Services Ltd | Information & communication | 2019 |
| JC Construction Consultancy Ltd | Professional & scientific | 2024 |
| JC Groen Consulting Limited | Information & communication | 2019 |
| JC Scada Services Ltd | Professional & scientific | 2021 |
| JCH Associates Limited | Professional & scientific | 2023 |
| JCH Brickwork Ltd | Construction | 2022 |
| JCJ Consulting Limited | Information & communication | 2024 |
| Jcjn Limited | Professional & scientific | 2021 |
| JD Financial Consulting Limited | Professional & scientific | 2024 |
| Jdata Solutions Ltd | Information & communication | 2025 |
| JDL Security Services Ltd | Construction | 2019 |
| JDR Digital Ltd | Information & communication | 2018 |
| JDW Academy Ltd | Other services | 2021 |
| JDW Aviation Consulting Ltd | Information & communication | 2016 |
| JDX Solutions Limited | Information & communication | 2007 |
| Jdyf Limited | Information & communication | 2023 |
| Jeff Hart Associates Ltd | Administrative & support | 2011 |
| Jefm Consultants Limited | Information & communication | 2019 |
| JEG Consultancy Limited | Professional & scientific | 2025 |
| JEM Consulting Ltd | Information & communication | 2023 |
| Jenhan Engineering Limited | Professional & scientific | 2016 |
| Jennifer Beales & Associates Limited | Professional & scientific | 2009 |
| Jenny Noscoe Garden Design Ltd | Administrative & support | 2016 |
| Jeraldo Consulting Ltd | Professional & scientific | 2024 |
| Jessica Kane Limited | Professional & scientific | 2016 |
| JF Ferris Ltd | Construction | 2024 |
| JFS Digital Consulting Ltd | Professional & scientific | 2018 |
| JFS Travel Limited | Transport & logistics | 2024 |
| JH Professional Services Limited | Professional & scientific | 2013 |
| JH Wealth Limited | Financial services | 2017 |
| JID Carpentry and Building Ltd | Manufacturing | 2026 |
| JIH Services Limited | Information & communication | 2020 |
| Jim's Cheesecakes (Ferndown) Ltd | Hospitality | 2024 |
| Jim's Cheesecakes (Wimborne) Ltd | Hospitality | 2023 |
| Jim's Cheesecakes Ltd | Hospitality | 2021 |
| Jima Group Ltd | Financial services | 2022 |
| Jitb Ltd | Professional & scientific | 2022 |
| JJ Contract Services Limited | Professional & scientific | 2019 |
| JJ01 Limited | Real estate | 2021 |
| JJ02 Limited | Real estate | 2021 |
| Jjpl Associates Ltd | Professional & scientific | 2024 |
| JL Corinthian Ltd | Professional & scientific | 2015 |
| JLB Dorset Ltd | Wholesale & retail | 2024 |
| JLC Sales Solutions Ltd | Wholesale & retail | 2014 |
| JLP Studios Limited | Information & communication | 2019 |
| JLV Industries Ltd | Transport & logistics | 2022 |
| JM Composite Solutions Limited | Manufacturing | 2024 |
| JMB Horses & Ponies Limited | Agriculture & fishing | 2025 |
| JMD Mills Ltd | Information & communication | 2025 |
| JME Technology Ltd | Information & communication | 2026 |
| JMF Solutions Limited | Information & communication | 2021 |
| JMG Porsche Ltd | Wholesale & retail | 2012 |
| JMG Property Group Limited | Professional & scientific | 2005 |
| JMO Enterprises Ltd | Professional & scientific | 2024 |
| Jmrs Consulting Limited | Information & communication | 2002 |
| JMT Direct Limited | Wholesale & retail | 2025 |
| JMT Real Estate Limited | Real estate | 2016 |
| JN IT Work Ltd | Information & communication | 2011 |
| JN Services Limited | Professional & scientific | 2024 |
| JO Darley & Co. Ltd | Other services | 2018 |
| Joanne Young Consultancy Ltd | Professional & scientific | 2023 |
| Jobatar Ltd | Information & communication | 2013 |
| Jobbooker Ltd | Information & communication | 2025 |
| Joco Tech Ltd | Information & communication | 2021 |
| Jocole Ltd | Professional & scientific | 2024 |
| JOE Manley Property Limited | Real estate | 2023 |
| Joe's MOT Limited | Wholesale & retail | 2015 |
| Joel IT Consultancy Limited | Information & communication | 2024 |
| John March (Firearms) Limited | Wholesale & retail | 1977 |
| John Pickett Master Thatcher Limited | Construction | 2014 |
| Johnson & Sons Homes Ltd | Professional & scientific | 2022 |
| Jolietech Ltd | Information & communication | 2022 |
| Jomo Barbers Limited | Other services | 2024 |
| JON Coombes Flooring Ltd | Construction | 2017 |
| Jonathan Neill Consulting Limited | Professional & scientific | 2017 |