| Jack Owen Transport Ltd | Transport & logistics | 2025 |
| Jack's Construction Repair Surgeon Ltd | Other services | 2019 |
| Jack's Tipple Ltd | Hospitality | 2019 |
| Jacks Civils Limited | Construction | 2025 |
| Jackson & Bohen Limited | Other services | 2026 |
| Jackson Geotechnics Limited | Professional & scientific | 2025 |
| Jackson Woodworks Ltd | Construction | 2016 |
| Jackson's Builders (Barnsley) Limited | Construction | 2018 |
| Jacksons Building Contractors Limited | Construction | 2002 |
| Jacolotte Investments Ltd | Financial services | 2025 |
| Jacques Orchard Management Company Limited | Households | 2020 |
| Jacquet (UK) Limited | Manufacturing | 1996 |
| Jade City Barnsley Limited | Hospitality | 2016 |
| Jade Training and Development Ltd. | Professional & scientific | 2014 |
| JAG - Adhesives, Binders & Coatings Limited | Construction | 2023 |
| Jagkul Ltd | Wholesale & retail | 2022 |
| Jagm Ltd | Construction | 2025 |
| JAK Engineering Supplies Limited | Construction | 2014 |
| Jakto Group Limited | Financial services | 2017 |
| Jakto Holdings Limited | Professional & scientific | 2009 |
| Jakto Transport Limited | Transport & logistics | 1985 |
| Jalco Ventures Ltd | Administrative & support | 2026 |
| Jalicko Limited | Professional & scientific | 2018 |
| JAM Designed Limited | Manufacturing | 2002 |
| JAM Motorsport Ltd | Wholesale & retail | 2025 |
| James & SON Services Ltd | Construction | 2024 |
| James Austerberry Limited | Wholesale & retail | 2014 |
| James Bentley Limited | Construction | 2016 |
| James Christian Financial Planning Limited | Financial services | 2020 |
| James Joseph Franklyn Homes Ltd | Real estate | 2024 |
| James Kilner Limited | Construction | 2021 |
| James Lawton & Associates Ltd | Financial services | 2015 |
| James Rose Lettings Ltd | Real estate | 2025 |
| James Shires & Sons Limited | Manufacturing | 1957 |
| James Thomas Limited | Construction | 2000 |
| James Trafford Marketing Limited | Information & communication | 2020 |
| Jamie Steele Joinery Ltd | Construction | 2026 |
| Janark Medical Limited | Health & social care | 2016 |
| Jandsassetts Ltd | Administrative & support | 2025 |
| Janice Jane Cosmetics Limited | Other services | 2012 |
| Janu & Divya Limited | Wholesale & retail | 2024 |
| Jap-Trans Limited | Wholesale & retail | 2017 |
| Jarc Properties Limited | Construction | 2025 |
| Jarral Foods Ltd | Hospitality | 2017 |
| Jarral Samuel Limited | Real estate | 2016 |
| Jasomel Limited | Real estate | 2017 |
| Jason Cupitt Golf Ltd | Wholesale & retail | 2023 |
| Jason.J.Beecroft Limited | Other services | 2016 |
| Jasper Wolf | Financial services | 2024 |
| Jatts Solutions Ltd | Construction | 2025 |
| Jaty Stone Limited | Construction | 2021 |
| JAW Legal Consultancy Ltd | Professional & scientific | 2014 |
| Jawcommunication Limited | Extraterritorial | 2014 |
| JAX Makama Design Professional Limited | Professional & scientific | 2025 |
| JAX Makama Development Properties Limited | Construction | 2025 |
| JAX Makama Diligent Cleaning Limited | Administrative & support | 2025 |
| JAY Ganesha Ltd | Transport & logistics | 2019 |
| Jaybird Properties Limited | Construction | 2015 |
| Jazzie Concept Limited | Professional & scientific | 2015 |
| JB Autos Mobile Vehicle Technician Ltd | Wholesale & retail | 2022 |
| JB Interior Solutions Limited | Wholesale & retail | 2023 |
| JB Legi Textus Laboris Limited | Other services | 2020 |
| JB Renovations (Yorkshire) Limited | Construction | 2021 |
| JBK Carriers Limited | Transport & logistics | 2018 |
| JBS Developments Limited | Real estate | 2008 |
| JC UK Highway Services Limited | Professional & scientific | 2012 |
| JC Visuals Ltd | Information & communication | 2025 |
| JCF Limited | Administrative & support | 2003 |
| JCH Property Developments Ltd | Real estate | 2026 |
| JCI Enterprises Limited | Real estate | 2023 |
| JCK Healthcare Limited | Health & social care | 2013 |
| JCM Building Developments Ltd | Real estate | 2025 |
| JCM Electrical & Construction Ltd | Construction | 2020 |
| JCS Homes Ltd | Real estate | 2025 |
| Jcsh Limited | Financial services | 2025 |
| JCT Construction Ltd | Construction | 2026 |
| Jctrade Ltd. | Wholesale & retail | 2017 |
| JD Babilon Ltd | Wholesale & retail | 2021 |
| JD Central Ltd | Administrative & support | 2018 |
| JD MCK Holdings Limited | Financial services | 2021 |
| JD Mortgage Solutions Ltd | Financial services | 2023 |
| JD Property (Yorkshire) Limited | Real estate | 2025 |
| JD SW Ltd | Health & social care | 2018 |
| JD Transport Support Services Limited | Transport & logistics | 2021 |
| JDC Haulage Ltd | Transport & logistics | 2019 |
| JDL Delivery Ltd | Transport & logistics | 2025 |
| JDM Draughting Services Limited | Professional & scientific | 2006 |
| Jdms Property Ltd | Construction | 2021 |
| JDS Construction & Civil Engineering Ltd | Construction | 2019 |
| JDS Designs Ltd | Professional & scientific | 2014 |
| JE Architectural Limited | Professional & scientific | 2011 |
| Jecos Holdings Limited | Financial services | 2025 |
| Jedson Composite Doors Limited | Manufacturing | 2004 |
| JEF Packaging Ltd | Manufacturing | 2019 |
| Jeff Epton Limited | Construction | 2022 |
| Jefs Engineering Limited | Professional & scientific | 2024 |
| JEL Investments Ltd | Real estate | 2019 |
| Jenkin House Management Company Limited | Households | 2016 |
| Jenkins Media Ltd | Information & communication | 2007 |
| Jennah Limited | Hospitality | 2013 |