| J.L. Vans Ltd | Wholesale & retail | 2005 |
| J.L.J. Effluent Engineering Limited | Water & waste | 1996 |
| J.L.J. Holdings Limited | Construction | 1996 |
| J.L.J. Properties Limited | Real estate | 1996 |
| J.O.M. Construction Limited | Construction | 1997 |
| J.P.B Electrical Solutions Ltd | Construction | 2019 |
| J.P.H. Ludolf Ltd | Professional & scientific | 1999 |
| J.Punshon & SON Limited | Wholesale & retail | 1961 |
| J.S. Financial Strategies Limited | Administrative & support | 2000 |
| J.Vickerstaff & Co.Limited | Wholesale & retail | 1920 |
| J.W. Painters & Decorators Limited | Construction | 2006 |
| J.W.& A.Seddon(Prescot)Limited | Real estate | 1944 |
| J.W.Properties Warrington Ltd | Real estate | 2014 |
| J1ONW Developments Ltd | Administrative & support | 2023 |
| J2BTC Ltd | Information & communication | 2019 |
| J3 Consulting Limited | Professional & scientific | 2016 |
| J3A Recruitment Ltd | Administrative & support | 2022 |
| J3G Consulting Limited | Administrative & support | 2013 |
| J9 Events Ltd | Arts & recreation | 2013 |
| JA Construction (Lymm) Limited | Other services | 2007 |
| JA Flooring Limited | Construction | 2012 |
| JA96 Limited | Financial services | 2020 |
| JAB Drafting Services Limited | Administrative & support | 2016 |
| Jabrada Consultancy Limited | Information & communication | 2017 |
| Jabula Consulting Ltd | Administrative & support | 2023 |
| Jacappella Limited | Education | 2002 |
| Jacar Ltd | Financial services | 2026 |
| Jack Longton Life Coaching Limited | Professional & scientific | 2025 |
| Jack's Express Ltd. | Wholesale & retail | 2023 |
| Jackson NPI Management Solutions Limited | Professional & scientific | 2017 |
| Jackson Projects Ltd | Professional & scientific | 2019 |
| Jackson Safety Services Ltd | Professional & scientific | 2017 |
| Jackson Signs Ltd | Other services | 2024 |
| Jackson Stephen Accountants & Business Advisers Limited | Professional & scientific | 2006 |
| Jackson Stephen LLP | | 2003 |
| Jacksons Mail Order Limited | Wholesale & retail | 2004 |
| Jackwood Investments Ltd | Real estate | 2019 |
| Jacob Bespoke Furniture Limited | Manufacturing | 2012 |
| Jacob's Workwear Ltd | Wholesale & retail | 2023 |
| Jacs Consultancy Ltd | Administrative & support | 2023 |
| Jada Consulting Ltd | Professional & scientific | 2025 |
| Jade Ashcroft Consulting Limited | Administrative & support | 2023 |
| Jademoon Ltd | Real estate | 2023 |
| Jaeaj Ltd | Real estate | 2021 |
| Jaffri Property Ltd | Real estate | 2010 |
| Jaffri Property Maintenance Limited | Real estate | 2015 |
| JAG Banga Ltd | Administrative & support | 2022 |
| Jagiesky Property Limited | Real estate | 2024 |
| Jagseven Limited | Information & communication | 2009 |
| Jahangir Arji Limited | Professional & scientific | 1995 |
| Jahnae Ltd | Wholesale & retail | 2022 |
| Jaidu UK Limited | Real estate | 2020 |
| Jajo Talent Ltd | Administrative & support | 2021 |
| JAK Tech Limited | Administrative & support | 2010 |
| Jake Carlin Properties Ltd | Real estate | 2023 |
| Jake Property Ltd | Real estate | 2025 |
| Jake's Makes Ltd | Other services | 2020 |
| Jakobec Projects Limited | Administrative & support | 2022 |
| JAL EIC Engineering Services Ltd | Professional & scientific | 2022 |
| Jalexat Consulting Limited | Professional & scientific | 2011 |
| Jallison CAD Ltd | Professional & scientific | 2018 |
| Jalo Property Ltd | Real estate | 2025 |
| JAM Clothing UK Ltd | Wholesale & retail | 2026 |
| JAM Engineering Services Limited | Construction | 2021 |
| JAM JAR Design Solutions Ltd | Professional & scientific | 2016 |
| Jama Projects Ltd | Administrative & support | 2024 |
| James & Co Consultancy Limited | Administrative & support | 2025 |
| James Clancy Consulting Limited | Professional & scientific | 2018 |
| James Clifford Associates Limited | Professional & scientific | 2014 |
| James Cran Ltd | Administrative & support | 2024 |
| James Dempster Design Ltd | Manufacturing | 2025 |
| James Gibbs Heating Services Limited | | 1980 |
| James H. Donald Company Services Limited | Other services | 2000 |
| James House Financial Strategies Limited | Administrative & support | 2009 |
| James Hunt Professional Services Ltd | Administrative & support | 2014 |
| James Lawrenson Interiors Ltd | Construction | 2016 |
| James Mcgeown Railway Ltd. | Construction | 2015 |
| James Peacock Property Sales and Management Limited | Real estate | 2014 |
| James R. Knowles (Holdings) Limited | Financial services | 1985 |
| James R. Knowles (Worldwide) Limited | Professional & scientific | 1981 |
| James Riley Associates (UK) Limited | Administrative & support | 2015 |
| James Rodriguez Ltd | Professional & scientific | 2015 |
| James Rose Construction Ltd | Other services | 2019 |
| James Tindall Cable Solutions Ltd | Administrative & support | 2026 |
| James Twist Garage Ltd | Wholesale & retail | 2003 |
| James&Sergiu Property Limited | Real estate | 2022 |
| Jamie Pitts Limited | Information & communication | 2017 |
| Jamie Watts Electrical Ltd | Administrative & support | 2023 |
| Jamieson Duffy Consultancy Ltd | Professional & scientific | 2024 |
| Jamin Solutions Limited | Information & communication | 2022 |
| JAN Shaw Property Holdings Limited | Real estate | 2003 |
| Jane Gowing Planning and Development Limited | Professional & scientific | 2015 |
| Jane Rennie Limited | Manufacturing | 2018 |
| Janet LO Consulting Limited | Professional & scientific | 2025 |
| Janix & Co Limited | Administrative & support | 2025 |
| Janmar Transport Ltd | Transport & logistics | 2023 |
| Janna Restaurant Limited | Hospitality | 2019 |
| Jannah Real Estate Ltd | Real estate | 2022 |
| Jarafin Tech Solutions Ltd | Other services | 2018 |
| Jarea Ltd | Real estate | 2024 |