| Jbas Investments Ltd | Real estate | 2022 |
| JBC Engineering (Cambs) Limited | Manufacturing | 2014 |
| JBC Holdings (Cambs) Limited | Financial services | 2025 |
| JBC Plant & Machinery Ltd | Construction | 2021 |
| JBJ Property Group Ltd | Households | 2026 |
| JBL Properties Ltd | Real estate | 2021 |
| JBM Digital Solutions Ltd | Information & communication | 2025 |
| JBP Legal Services Ltd | Professional & scientific | 2015 |
| JBR Property Limited | Real estate | 2023 |
| JBR Property Services Ltd | Real estate | 2025 |
| JBR Trading Limited | Wholesale & retail | 2021 |
| JBS Contracting Ltd | Construction | 2023 |
| JBS Training Limited | Education | 2022 |
| JC Carpenter & Joinery Ltd | Manufacturing | 2023 |
| JC EAT Ltd | Hospitality | 2025 |
| JC Funding Limited | Financial services | 2012 |
| JC Heating Services Limited | Construction | 2014 |
| JC Lazarini Transport Ltd | Transport & logistics | 2025 |
| JC Property Rental Limited | Real estate | 2022 |
| JCA Solutions Limited | Construction | 2026 |
| Jcar Properties Ltd | Real estate | 2025 |
| JCB Books & Publishing Limited | Wholesale & retail | 2026 |
| JCH Automation Ltd | Construction | 2024 |
| JCH Hallatt Limited | Construction | 2019 |
| Jchr Engineering Ltd | Professional & scientific | 2026 |
| JCN Sales & Consulting Ltd | Professional & scientific | 2025 |
| JCO Carpentry Limited | Administrative & support | 2009 |
| JCO Properties Ltd | Real estate | 2024 |
| JCT Property Solutions Limited | Real estate | 2017 |
| JCW Telecommunications Ltd | Information & communication | 2021 |
| JD AJK Construction Ltd | Construction | 2026 |
| JD Brook Limited | Extraterritorial | 2022 |
| JD Carter Limited | Construction | 2019 |
| JD Interior Solutions Limited | Construction | 2014 |
| JD Property Developers Limited | Real estate | 2022 |
| JDB Bookkeeping & Payroll Services Ltd | Professional & scientific | 2019 |
| JDB Labour Management Ltd | Administrative & support | 2022 |
| JDB Tax and Business Advisers Limited | Professional & scientific | 2009 |
| JDF Electrical Solutions Ltd | Construction | 2021 |
| JDM Collaborations Ltd | Real estate | 2019 |
| Jdna Ltd | Construction | 2020 |
| Jdrm Property Ltd | Real estate | 2025 |
| Jdwood Children's Services Ltd | Education | 2025 |
| Jdynamics Limited | Information & communication | 2025 |
| JE Training Limited | Arts & recreation | 2019 |
| Jeans & Jeans Ltd | Wholesale & retail | 2016 |
| JED Trans Ltd | Administrative & support | 2021 |
| Jeff Scothern Construction Services Ltd | Professional & scientific | 2015 |
| Jeffnet Ltd | Construction | 2025 |
| Jeiva Ltd | Other services | 2025 |
| Jellings Properties Limited | Real estate | 1973 |
| JEM Business Consulting Limited | Information & communication | 2022 |
| JEM Education Support Services Ltd | Manufacturing | 2017 |
| JEM Engineering and Fabrication Ltd | Manufacturing | 2020 |
| JEM Powder Coating Ltd | Manufacturing | 2025 |
| Jemtec Limited | Health & social care | 2008 |
| Jenscleans Ltd | Administrative & support | 2026 |
| Jensen Group Holdings Limited | Financial services | 2023 |
| Jensen Group Solutions Limited | Administrative & support | 1999 |
| Jensen Security & Fire Systems Ltd | Extraterritorial | 2024 |
| Jenson Cars Ltd | Wholesale & retail | 2010 |
| Jermac Holdings Ltd | Construction | 2023 |
| Jerrard Wayne Creatives Limited | Administrative & support | 2010 |
| JES Care Limited | Administrative & support | 2021 |
| Jesco Clean Limited | Administrative & support | 2025 |
| Jesionowski Logistics Ltd | Administrative & support | 2014 |
| Jesod Orphic Ltd | Real estate | 2015 |
| Jesper Developments Limited | Real estate | 2016 |
| Jessa Damani Limited | Real estate | 2020 |
| Jessema Ltd | Wholesale & retail | 2024 |
| Jessi Properties Limited | Real estate | 2020 |
| Jessica 1 Nails and Beauty Ltd | Other services | 2024 |
| JET Force Asset Management Ltd | Administrative & support | 2025 |
| JET2PALLETS Limited | Transport & logistics | 2024 |
| Jetodd Investments Limited | Financial services | 2013 |
| Jevgenpro Ltd | Transport & logistics | 2026 |
| JF Property Group Ltd | Real estate | 2018 |
| JF Yang Programme Management Consultancy Ltd | Professional & scientific | 2017 |
| JFK Holdings Limited | Financial services | 2025 |
| JG Capital Finance Limited | Financial services | 2023 |
| JG Digital Network Limited | Information & communication | 2025 |
| JG Multi Services Ltd | Wholesale & retail | 2016 |
| JG Property Experts Ltd | Construction | 2024 |
| JH Estates Ltd | Real estate | 2017 |
| JH Roofing & Building Solutions Ltd | Construction | 2025 |
| JH Wilson Automotive Limited | Wholesale & retail | 2025 |
| JHA Automotive Ltd | Wholesale & retail | 2025 |
| Jhalawan Limited | Hospitality | 2022 |
| JHC Consulting Limited | Health & social care | 2012 |
| Jhdtraining Ltd | Agriculture & fishing | 2022 |
| Jhmx Limited | Wholesale & retail | 2025 |
| JHS Wholesale Ltd | Wholesale & retail | 2018 |
| JHX Enterprises Ltd | Wholesale & retail | 2021 |
| JIG One Ltd | Professional & scientific | 2012 |
| Jiggy Bidco Limited | Financial services | 2025 |
| Jiggy Midco Limited | Financial services | 2025 |
| Jiggy Topco Limited | Financial services | 2025 |
| Jignesh Panchal Ltd | Real estate | 2019 |
| Jigowatt Limited | Information & communication | 2007 |
| JIM Barnett Ltd | Professional & scientific | 2024 |