| J&A Sushi Ltd | Hospitality | 2019 |
| J&A Tea House Ltd | Manufacturing | 2024 |
| J&B Elliott Services Limited | Information & communication | 2021 |
| J&D Transport and Logistics Ltd | Transport & logistics | 2026 |
| J&J Fire Solutions Ltd | Construction | 2025 |
| J&J Roofing Solutions Ltd | Construction | 2026 |
| J&L Access Consultants Limited | Construction | 2026 |
| J&L Everett Homes Ltd | Households | 2026 |
| J&R Medical Services Limited | Health & social care | 2015 |
| J&S Mini Market Ltd | Wholesale & retail | 2021 |
| J'Atelier Designed Jewelry Ltd | Wholesale & retail | 2021 |
| J. Bealby & Sons Limited | Agriculture & fishing | 1956 |
| J. M. Lean Coaching Limited | Professional & scientific | 2007 |
| J. Whittlestone & Sons Limited | Construction | 1984 |
| J.E.Wright(Home Heating Systems)Limited | Real estate | 1960 |
| J.H.R. Packaging Company Limited(The) | Manufacturing | 1980 |
| J.M.Hill Building Services Ltd | Construction | 2013 |
| J.T. Estates Property Limited | Real estate | 2015 |
| J.Talc Ltd | Real estate | 2019 |
| J2DIGITAL Limited | Information & communication | 2023 |
| J4CKIE-B Ltd | Manufacturing | 2024 |
| JA Woody (Holdings) Limited | Professional & scientific | 2013 |
| JAC Property Investments Limited | Real estate | 2023 |
| JAC Studio Limited | Professional & scientific | 2018 |
| Jacaranda Brewing Company Limited | Manufacturing | 2021 |
| Jacaranda Leisure Limited | Wholesale & retail | 2007 |
| Jack PK Ltd | Transport & logistics | 2017 |
| Jack Speed Ltd | Transport & logistics | 2020 |
| Jackputt.Co.Uk Ltd | Wholesale & retail | 2025 |
| Jackson and Birkett Ltd | Wholesale & retail | 2011 |
| Jacktradescards Ltd | Wholesale & retail | 2023 |
| Jacob Cooper Catering Ltd | Professional & scientific | 2025 |
| Jacob Residential Lettings Ltd | Real estate | 2023 |
| Jacobs Endo Ltd | Health & social care | 2022 |
| Jader Ltd | Information & communication | 2012 |
| Jaegen Ltd | Professional & scientific | 2018 |
| Jagkin Limited | Real estate | 2018 |
| Jagpal Properties Ltd | Real estate | 2020 |
| JAI Hind Consultants and Associates Limited | Administrative & support | 2025 |
| Jaivel Aerospace Limited | Professional & scientific | 2005 |
| Jaivel Ltd | Real estate | 2011 |
| JAK Property Group Ltd | Real estate | 2021 |
| JAK Tooth Developments Ltd | Real estate | 2024 |
| James Chapman Homes Limited | Construction | 2013 |
| James Events Ltd | Manufacturing | 2022 |
| James Francis Properties Ltd | Real estate | 2022 |
| James Professional Limited | Professional & scientific | 2016 |
| James Shelton Limited | Financial services | 2018 |
| Jamie Kisiel Electrical Ltd | Construction | 2024 |
| Jamieleamellors Ltd | Wholesale & retail | 2025 |
| Jammie Dodgers Childminding Group Ltd | Health & social care | 2026 |
| Janesta Ltd | Administrative & support | 2025 |
| Jano Trans Ltd | Transport & logistics | 2022 |
| Japanese Knotweed Specialists Limited | Agriculture & fishing | 2011 |
| Jarral Holdings Limited | Financial services | 2015 |
| Jason Sarson Associates Ltd | Information & communication | 2014 |
| Jassal Properties Ltd | Real estate | 2019 |
| JAY DEE Management Limited | Professional & scientific | 2019 |
| JAY Kays Care Limited | Public administration | 2026 |
| JAY Shanti Neil Limited | Wholesale & retail | 2006 |
| Jayesh Dave Manufacturing Consultant Limited | Professional & scientific | 2026 |
| Jayne Clarke Limited | Wholesale & retail | 2025 |
| Jazzy Robot Ltd | Wholesale & retail | 2024 |
| JB Vans Ltd | Wholesale & retail | 2025 |
| JBT Consultancy Ltd | Education | 2022 |
| JBT Group Holdings Ltd | Construction | 2023 |
| JBT Group Ltd | Construction | 2017 |
| JC Flues Ltd | Construction | 2023 |
| JC Orthopaedics Ltd | Health & social care | 2018 |
| JC Training & Consultancy Ltd | Education | 2016 |
| JCS Mortgage Services Ltd | Financial services | 2021 |
| JCT 29 Limited | Wholesale & retail | 2023 |
| JCT 29 Select Limited | Wholesale & retail | 2014 |
| JD Cyber Ltd | Information & communication | 2025 |
| JD Motor Co (Mansfield) Ltd. | Wholesale & retail | 2018 |
| JD Rose Projects Limited | Construction | 2025 |
| JDK Camper Vans & Conversions Ltd | Manufacturing | 2025 |
| JDT Delivery Ltd | Transport & logistics | 2023 |
| Jeevan Stores Limited | Wholesale & retail | 2014 |
| Jephsons Holdings Limited | Financial services | 2026 |
| Jephsons Shopfitters Holdings Limited | Professional & scientific | 2000 |
| Jephsons Shopfitters Limited | Construction | 1997 |
| Jervis ICI Ltd | Financial services | 2019 |
| Jesterhead Motorsport Ltd | Wholesale & retail | 2025 |
| JET Press Shirebrook Limited | Manufacturing | 1986 |
| Jetas Media Limited | Information & communication | 2022 |
| Jetframe Limited | Real estate | 1987 |
| Jetsetter Services Limited | Transport & logistics | 2025 |
| Jettmaxwell Ltd | Wholesale & retail | 2025 |
| Jewellery Guru.Com Ltd | Administrative & support | 2019 |
| JG Immo Ltd | Real estate | 2017 |
| Jgpm.Construction Ltd | Construction | 2018 |
| JGS4YOU Ltd | Wholesale & retail | 2025 |
| JH Health Ltd | Health & social care | 2024 |
| JH Legal Ltd | Professional & scientific | 2017 |
| JH Sons Property Limited | Real estate | 2025 |
| JHW Sand Ltd | Professional & scientific | 2025 |
| Jigsaw Fibre Limited | Information & communication | 2023 |
| Jigsaw Homecare Ltd | Health & social care | 2013 |
| JIK Limited | Real estate | 2001 |