| Jade Whisper Limited | Wholesale & retail | 2003 |
| Jadu Management Ltd | Information & communication | 2020 |
| JAG Commodities Ltd | Wholesale & retail | 2021 |
| Jagatia Desserts Ltd | Manufacturing | 2023 |
| Jaghuri Limited | Hospitality | 2023 |
| Jagpal Engineering Limited | Manufacturing | 2003 |
| Jagpal Ltd | Administrative & support | 2025 |
| Jaguar Drivers'Club Limited(The) | Other services | 1958 |
| JAH Finance Solutions Ltd. | Professional & scientific | 2015 |
| Jaich Holdings Limited | Financial services | 2025 |
| Jain Capital Holdings Limited | Financial services | 2021 |
| Jain Properties Limited | Real estate | 2018 |
| Jaja World Ltd | Wholesale & retail | 2018 |
| Jakefield Property Ltd | Households | 2025 |
| Jalalabadi Property Holdings Ltd | Financial services | 2026 |
| Jalalabadi Property Investments Ltd | Real estate | 2026 |
| Jamar Properties Limited | Real estate | 1978 |
| Jamco Services Ltd | Professional & scientific | 2024 |
| James Allen & Son(Disley)Limited | Extraterritorial | 1968 |
| James Crook Limited | Extraterritorial | 1995 |
| James Leigh Rubber and Plastics Limited | Manufacturing | 1997 |
| James Madison Homes Limited | Extraterritorial | 2016 |
| James Madison Services LLP | | 2011 |
| James Parkes Ltd | Manufacturing | 2015 |
| Jamie Bunch Sports Consultancy Ltd | Professional & scientific | 2022 |
| Jams Solutions & Services Ltd | Wholesale & retail | 2022 |
| Jamv Limited | Health & social care | 2019 |
| Janani Ltd | Health & social care | 2023 |
| Janet James Development Company Limited | Construction | 2018 |
| JAP (Birmingham) Ltd | Transport & logistics | 2023 |
| Jaqks Ltd | Real estate | 2010 |
| JAR Consultancy Limited | Information & communication | 2010 |
| JAR Solar Ltd | Construction | 2023 |
| Jara Residential Ltd | Real estate | 2017 |
| Jari KAS Transport (1963) Ltd | Extraterritorial | 2022 |
| Jari KAS Transport Ltd | Extraterritorial | 2026 |
| Jarra Associates Ltd | Wholesale & retail | 2016 |
| Jask Healthcare Limited | Real estate | 2025 |
| Jasmin Advisory LLP | | 2015 |
| Jatp Trading Limited | Health & social care | 2013 |
| Jaul Glass Ltd | Construction | 2025 |
| JAX Holdings Limited | Professional & scientific | 2015 |
| Jayce's World Ltd | Wholesale & retail | 2023 |
| Jayce's World of Learning CIC | Education | 2024 |
| Jayes Properties Ltd | Real estate | 2023 |
| Jaygee Property Management Ltd | Real estate | 2023 |
| Jays Tyres Ltd | Wholesale & retail | 2025 |
| JAZ Gharu Ltd | Administrative & support | 2016 |
| JB Aesthetics Limited | Health & social care | 2011 |
| JB Connect Consulting Ltd | Professional & scientific | 2024 |
| JB Investments Group Limited | Financial services | 2020 |
| JC Building Inspections Limited | Professional & scientific | 2010 |
| JC Central Ltd | Professional & scientific | 2019 |
| JC Exclusive Investments Limited | Real estate | 2024 |
| Jccuk Ltd | Transport & logistics | 2023 |
| JCP Property Investments Limited | Real estate | 2020 |
| JD Allfloors Limited | Construction | 2018 |
| JD Leisure Holdings Limited | Hospitality | 2015 |
| JD Morris Property Ltd | Real estate | 2017 |
| JDB Electrical Solutions Limited | Construction | 2019 |
| JDE Global Limited | Transport & logistics | 2025 |
| JDE Investments Limited | Real estate | 2022 |
| Jdeee Limited | Real estate | 2021 |
| JDL Wealth Limited | Professional & scientific | 2020 |
| JDM Housing Limited | Real estate | 2024 |
| JDR Midlands Limited | Real estate | 2024 |
| Jdtn Ltd | Hospitality | 2021 |
| JED Kurzel Ltd | Arts & recreation | 2016 |
| Jedasher Holdings Limited | Health & social care | 2023 |
| Jedi Limited | Real estate | 2025 |
| Jeera Limited | Hospitality | 2021 |
| Jeerh Limited | Hospitality | 2026 |
| Jeff Neal Site Management Limited Limited | Construction | 2015 |
| Jefff Ltd | Agriculture & fishing | 2021 |
| JEM 21 Limited | Hospitality | 2014 |
| Jems Properties Buy & LET Limited | Real estate | 2026 |
| JEN Johnston Music Ltd | Education | 2022 |
| Jeremy George Lake Financial Services Ltd | Professional & scientific | 2016 |
| Jessica Jane Enterprises Ltd | Wholesale & retail | 2026 |
| JET SET International Limited | Real estate | 2025 |
| Jetcast Plumbing & Drainage Services Limited | Construction | 2010 |
| Jetour UK Ltd | Wholesale & retail | 2026 |
| Jetsa Group Limited | Wholesale & retail | 2019 |
| Jewellery Quarter Consultancy Limited | Professional & scientific | 2023 |
| Jeyam Express Ltd | Wholesale & retail | 2023 |
| Jeymer Limited | Households | 2015 |
| Jezel Limited | Real estate | 2018 |
| JF Truman Limited | Administrative & support | 2017 |
| JFR Accountancy Limited | Professional & scientific | 2006 |
| JG Joall Properties Ltd | Real estate | 2023 |
| JG Training Solutions Ltd | Education | 2023 |
| JGS Animal Services Ltd | Agriculture & fishing | 2023 |
| JH Air Conditioning Limited | Energy | 2023 |
| JH Equestrian Services Limited | Agriculture & fishing | 2019 |
| JH Hayler Ltd | Information & communication | 2021 |
| JH New Roof Specialist Ltd | Construction | 2018 |
| JHS Property Investment Limited | Real estate | 2024 |
| Jhwconsultants LLP | | 2023 |
| Jigsaw Business Performance Management Limited | Administrative & support | 2014 |
| Jigsaw Installations Limited | Construction | 2018 |