| J MAC Excavators Ltd | Wholesale & retail | 2018 |
| J P Search Solutions Ltd | Other services | 2025 |
| J Patel Enterprises Ltd. | Wholesale & retail | 2013 |
| J Phelan Electrical Ltd | Construction | 2025 |
| J Phelan Investments Ltd | Real estate | 2025 |
| J R Engineering Solutions Limited | Manufacturing | 2002 |
| J S Roofing and Solar Ltd | Construction | 2023 |
| J T Project Limited | Professional & scientific | 2008 |
| J T Vets Limited | Professional & scientific | 2009 |
| J W Insulation Services Limited | Construction | 2010 |
| J&A Distributors Ltd | Wholesale & retail | 2025 |
| J&A Property Solutions Ltd | Real estate | 2020 |
| J&A Seafoods Limited | Financial services | 2024 |
| J&M Investment Ltd | Real estate | 2008 |
| J&R Build Ltd | Construction | 2022 |
| J&S Construction (2015) Limited | Construction | 2014 |
| J&S Innovations Ltd | Wholesale & retail | 2024 |
| J&W Jewellery Limited | Wholesale & retail | 2021 |
| J-Unit Wood Recycling Ltd | Administrative & support | 2019 |
| J. & F. Pool Limited | Professional & scientific | 1905 |
| J. Collins & Company (Jewellers) Limited | Manufacturing | 1950 |
| J. D. Flowers Limited | Wholesale & retail | 2008 |
| J. Dodd & SON (Contractors) Limited | Construction | 1980 |
| J. L. Building Limited | Construction | 2006 |
| J. M. Bailey Communications Limited | Professional & scientific | 1992 |
| J. Walton Electrical Ltd | Construction | 2004 |
| J.C. Trophies Limited | Manufacturing | 2002 |
| J.D. Hampton Ltd | Construction | 2020 |
| J.D. Steele Ltd | Construction | 2020 |
| J.H.S. Limited | Real estate | 1998 |
| J.J. Webley Limited | Transport & logistics | 2017 |
| J.M. Ellis (Holdings) Limited | Administrative & support | 1997 |
| J.M.Roofing Limited | Construction | 2007 |
| J.Mccbuild Ltd | Construction | 2020 |
| J.Mccrenovations Ltd | Construction | 2020 |
| J.P Montvell Ltd | Wholesale & retail | 2025 |
| J.P. Electrical & Mechanical Services Limited | Administrative & support | 2003 |
| J.P. Hare (Consultants) Limited | Professional & scientific | 1997 |
| J.R. Edwards Financial Limited | Professional & scientific | 2012 |
| J.R. Hartley Limited | Real estate | 2018 |
| J.Sondh Cleaning Limited | Administrative & support | 2023 |
| J.Sondh Property Ltd | Real estate | 2023 |
| J.T. Edwards and Sons Ltd. | Real estate | 2000 |
| J.W.S Interiors Limited | Construction | 2009 |
| J2 Vibe Limited | Real estate | 2024 |
| JA Gardner Property Services Limited | Construction | 2017 |
| JA Racing Ltd | Wholesale & retail | 2016 |
| Jaas Trading Ltd | Wholesale & retail | 2024 |
| JAB Professional Services Limited | Professional & scientific | 2023 |
| JAC Advisory Ltd | Professional & scientific | 2025 |
| Jack Honnor Services Ltd | Construction | 2022 |
| Jack JAY Ltd | Extraterritorial | 2018 |
| Jack of ALL Trade Construction Ltd | Construction | 2024 |
| Jack of Cars Ltd | Wholesale & retail | 2020 |
| Jack Shakespeare Ltd | Construction | 2024 |
| Jackfrags Limited | Information & communication | 2014 |
| Jackson's of Henley Limited | Wholesale & retail | 1986 |
| Jacksons of Henley Services Limited | Financial services | 2024 |
| Jacobs Bond Pascoe Ltd | Professional & scientific | 2014 |
| Jacross Enterprises Ltd | Health & social care | 2005 |
| Jadiva & DU Co. Ltd | Wholesale & retail | 2025 |
| JAE Civils Ltd | Construction | 2025 |
| Jafss Ltd | Real estate | 2018 |
| JAFSS2 Ltd | Real estate | 2023 |
| JAG Aviation Services Ltd | Manufacturing | 2024 |
| Jago Analysis Limited | Administrative & support | 2013 |
| Jaguartech (Warwick) Ltd | Information & communication | 2012 |
| JAI Atwal Ltd | Financial services | 2006 |
| JAI Brow Bar Limited | Other services | 2007 |
| JAI Marnie KB Properties Ltd | Real estate | 2022 |
| JAI P8-10 Convenience Stores Ltd | Wholesale & retail | 2022 |
| JAI Properties Limited | Real estate | 1992 |
| Jajo Limited | Information & communication | 2013 |
| JAK Improvements Ltd | Construction | 2020 |
| Jakbed Limited | Manufacturing | 2017 |
| JAKBED1 Ltd | Manufacturing | 2021 |
| Jakco Space Engineering Limited | Manufacturing | 2014 |
| Jakson Limited | Information & communication | 2025 |
| Jalon Ltd | Other services | 2006 |
| JAM Interiors Solihull Ltd | Wholesale & retail | 2023 |
| JAM People Consulting Limited | Administrative & support | 2019 |
| Jamb Property Solutions Ltd | Real estate | 2017 |
| James B Properties Ltd | Real estate | 2018 |
| James Bowie Limited | Construction | 2012 |
| James Building Conservation Limited | Construction | 2014 |
| James Bushell Boutique Limited | Other services | 2016 |
| James Bushell Hair Ltd | Other services | 2013 |
| James Field Kitchens Ltd | Construction | 2021 |
| James French Counselling Ltd | Health & social care | 2023 |
| James Hartley Commercials Ltd | Wholesale & retail | 2025 |
| James Mathew Shaw Consultancy Limited | Professional & scientific | 2019 |
| James Murray Engineering Limited | Information & communication | 2009 |
| James Olivia Limited | Other services | 2017 |
| James Smith & SON Redditch Limited | Other services | 1900 |
| James Wilson Special Effects Ltd | Manufacturing | 2023 |
| Jamestead Group Ltd | Professional & scientific | 2025 |
| Jamia Heddaria Mujajjadia Birmingham Limited | Administrative & support | 2014 |
| Jamie Carney Golf Shop Ltd | Arts & recreation | 2019 |
| Jamie Mullan Limited | Construction | 2013 |
| Jamjar Design Limited | Professional & scientific | 2006 |