| Jagia Ltd | Other services | 2025 |
| Jaidan Consultancy Ltd | Professional & scientific | 2021 |
| Jaidan Events Ltd | Hospitality | 2022 |
| Jaiss Ltd | Professional & scientific | 2026 |
| Jalfies Convenience Ltd | Wholesale & retail | 2023 |
| James Moore Communications Ltd | Information & communication | 2021 |
| Jamk Care Ltd | Other services | 2015 |
| JAN Mcdermott & Co. Limited | Professional & scientific | 2005 |
| Jane Louise Ltd | Health & social care | 2025 |
| Janos SZE Limited | Transport & logistics | 2025 |
| Japex Ltd | Construction | 2025 |
| Jarrod Homer Ltd | Health & social care | 2011 |
| Jasmine Commercial and Residential Property Ltd | Real estate | 2018 |
| Jayz Property Solutions Ltd | Real estate | 2025 |
| JC Comics & Games Ltd | Wholesale & retail | 2018 |
| Jc&Me Property Limited | Real estate | 2019 |
| Jccwong Limited | Health & social care | 2023 |
| JCN International Ltd | Wholesale & retail | 2026 |
| Jcph Limited | Real estate | 2021 |
| JD Aerial Fitness Academy Limited | Arts & recreation | 2020 |
| Jeanette Roberts Celebrant Limited | Other services | 2023 |
| Jeff Harris Roofing Services Limited | Construction | 2008 |
| JEH Engineering Consultants Ltd | Professional & scientific | 2025 |
| JEL Electrical Limited | Construction | 2001 |
| Jelley Bakes Ltd | Manufacturing | 2023 |
| Jennifer Tomlinson Estates Limited | Real estate | 2022 |
| Jenny Beautifiers Limited | Wholesale & retail | 2025 |
| JET Clean N/W Ltd | Other services | 2016 |
| JET Rigging and Lifting Limited | Manufacturing | 2016 |
| Jettin Ltd | Wholesale & retail | 2025 |
| JF Law Limited | Professional & scientific | 2014 |
| Jfowler Ltd | Construction | 2026 |
| Jimmy’S Beer & GAS (Wirral) Limited | Wholesale & retail | 2017 |
| Jiyan Chef Ltd | Construction | 2020 |
| JJ Capital Management Limited | Professional & scientific | 2022 |
| JJ Classic Restorations Limited | Construction | 2023 |
| JJS Accounting Services Limited | Professional & scientific | 2025 |
| JJS Hygienic Wall Systems Holdings Ltd | Construction | 2022 |
| Jjsc Properties Ltd | Real estate | 2026 |
| JKP Coaching Limited | Professional & scientific | 2022 |
| JKP Football Academy Limited | Arts & recreation | 2026 |
| JKP Mentoring Limited | Education | 2025 |
| JKP Mindful Messi's CIC | Education | 2023 |
| JL Bennett Consultancy Ltd | Professional & scientific | 2023 |
| Jlmc Solutions Limited | Professional & scientific | 2013 |
| JLO Properties (Lancs) Ltd | Real estate | 2024 |
| JM Leicester Roofing Ltd | Construction | 2025 |
| Jm-Precision Fabrication & Welding Ltd. | Manufacturing | 2017 |
| JMP Window Systems Limited | Construction | 2007 |
| JMV Orthopaedics Limited | Health & social care | 2022 |
| JMW Kitchens and Bathrooms Ltd | Construction | 2019 |
| JN Consulting NW Ltd | Professional & scientific | 2025 |
| JNA Consult Ltd | Professional & scientific | 2025 |
| JO Jacques Health and Beauty Limited | Administrative & support | 2004 |
| Joanne Brown Consultancy Limited | Education | 2025 |
| Joanne Brown Property Company Limited | Real estate | 2026 |
| JOC Performance Ltd | Wholesale & retail | 2025 |
| Jodee Limited | Real estate | 2016 |
| JOE Ward Body Transformation Coach Ltd | Arts & recreation | 2024 |
| Joe's Lodge Limited | Hospitality | 2005 |
| John Beech Limited | Water & waste | 1963 |
| John Forbes Accountancy Limited | Professional & scientific | 2021 |
| John Forbes Consulting LLP | | 2013 |
| John Pennington Consultancy Services Limited | Professional & scientific | 2016 |
| John T.Smith (Brick) Limited | Construction | 1954 |
| Johnclo Ltd | Wholesale & retail | 2024 |
| Johnson Foundation(The) | Health & social care | 1987 |
| Johnson I.T. Consultancy Ltd | Information & communication | 2018 |
| Johnston Building & Design Limited | Construction | 2018 |
| Johnston Capital Investment Ltd | Financial services | 2023 |
| Jones AV Limited | Other services | 2008 |
| Jones Clynch Consulting Ltd | Professional & scientific | 2025 |
| Jones Garbett Advisers Ltd | Financial services | 2025 |
| Jones Kinvig Lawyers Ltd | Professional & scientific | 2011 |
| Joro Vegan Eatery Ltd | Hospitality | 2017 |
| Josh Sutton Coaching Ltd | Professional & scientific | 2026 |
| Journeymen CIC | Other services | 2025 |
| Joynson Investments Ltd | Financial services | 2021 |
| Joynson Pharmacy Ltd | Wholesale & retail | 2023 |
| JP & Sons Retail Ltd | Wholesale & retail | 2023 |
| JPB 23 Ltd | Professional & scientific | 2024 |
| JPD Care Services Ltd | Health & social care | 2025 |
| Jqcommercials Ltd | Professional & scientific | 2026 |
| JRD Property Development Limited | Real estate | 2020 |
| JS Insights Ltd | Information & communication | 2025 |
| JS Risk Limited | Administrative & support | 2023 |
| JS Wedding Services Limited | Arts & recreation | 2016 |
| Jsashworth Ltd | Real estate | 2022 |
| JTG Joinery & Building Ltd | Construction | 2021 |
| Juhdia Ltd | Hospitality | 2025 |
| Juke PUB Co Limited | Hospitality | 2019 |
| Jules 1 Studios Ltd | Information & communication | 2025 |
| Julia Zelg Entertainment Ltd | Professional & scientific | 2020 |
| July Twenty Two Limited | Administrative & support | 2026 |
| Jungle Parc Irchester Ltd | Arts & recreation | 2012 |
| Jungle Parc Swindon Ltd | Arts & recreation | 2012 |
| Junk Removal in London Limited | Transport & logistics | 2025 |
| Jurisg Transport Ltd | Transport & logistics | 2022 |
| Just Developing Limited | Construction | 2021 |
| Just Rental Properties Limited | Real estate | 2016 |