| J J Mccrae Limited | Real estate | 2016 |
| J Jose Investments Ltd | Real estate | 2019 |
| J K & SON Property Management Ltd | Real estate | 2022 |
| J Kendall Ltd | Health & social care | 2024 |
| J Mcmahon Limited | Construction | 2012 |
| J P TAN Limited | Real estate | 2020 |
| J P U Investments Limited | Real estate | 2021 |
| J R Estate Agents Limited | Real estate | 1992 |
| J Sellwood Designs Limited | Professional & scientific | 2012 |
| J W N Brickwork Ltd | Construction | 2008 |
| J&A FIO Developements Limited | Construction | 2021 |
| J&D Hygienist Ltd | Health & social care | 2023 |
| J&H Management Ltd | Real estate | 2019 |
| J&P Construction Ltd | Construction | 2016 |
| J&P Property Solutions Limited | Construction | 2022 |
| J&S Tours Ltd | Administrative & support | 2023 |
| J&Y Consultancy Ltd | Professional & scientific | 2024 |
| J. and B. Construction Co. Limited | Construction | 2000 |
| J. K. V. Pharma Limited | Other services | 2014 |
| J.Dep Motors Ltd | Wholesale & retail | 2009 |
| J.Donnan Decorating Ltd | Construction | 2026 |
| J.N.K. Motors Ltd. | Wholesale & retail | 1996 |
| J.P.V. (Painters) Limited | Construction | 1973 |
| J.R. Heffer Investments Limited | Real estate | 1965 |
| J.R.J. Heating Services Ltd | Construction | 2017 |
| J.S. Woolley & Co Ltd | Real estate | 2023 |
| J1 Property Services Ltd | Real estate | 2020 |
| J2P Autos Ltd | Financial services | 2018 |
| JA Advisors Ltd | Financial services | 2014 |
| JA Recruitment Holdings Ltd | Financial services | 2025 |
| Jaasa Limited | Financial services | 2023 |
| Jabbal SMG Accountants Ltd | Professional & scientific | 2014 |
| Jaccarino Limited | Real estate | 2026 |
| Jack the MAN Maintenance Ltd | Construction | 2024 |
| Jacobelle Ltd | Real estate | 2020 |
| Jacobs the Jewellers LLP | | 2021 |
| Jacota Groundworks Ltd | Construction | 2025 |
| Jacques Amand International Limited | Wholesale & retail | 2006 |
| Jade Corporate Limited | Other services | 1994 |
| JAE Groundworks Limited | Extraterritorial | 2008 |
| Jaes Solutions Ltd | Information & communication | 2023 |
| Jahany Limited | Information & communication | 2023 |
| Jain Builders Ltd | Real estate | 2025 |
| Jain Spirit Limited | Extraterritorial | 2009 |
| Jaina Shah Investments Ltd | Professional & scientific | 2020 |
| Jaiya Builders Limited | Construction | 2019 |
| Jalaram Holdco Limited | Real estate | 2020 |
| Jalaram Investments Limited | Real estate | 2020 |
| Jambo Global Consulting Ltd | Professional & scientific | 2026 |
| James Perring Agencies Limited | Wholesale & retail | 2020 |
| James Prescott Ltd | Professional & scientific | 2023 |
| Janet Brinkworth Ltd | Information & communication | 2011 |
| Jannix Limited | Real estate | 2013 |
| Jannock PVT Ltd | Wholesale & retail | 2020 |
| Jarns Holdings Ltd | Financial services | 2025 |
| Jase Properties Ltd | Real estate | 2019 |
| Jaslex Limited | Construction | 2024 |
| Jasmin Care Limited | Health & social care | 2023 |
| Jasmine Gardens Company Limited | Households | 2005 |
| Jasmine P Limited | Other services | 2023 |
| Jast Retail Limited | Wholesale & retail | 2025 |
| Jateen Consulting Limited | Financial services | 2013 |
| Jawlstore Ltd | Wholesale & retail | 2024 |
| Jawov Holding Limited | Financial services | 2018 |
| JAY Ravi Randal MAA Ltd | Wholesale & retail | 2025 |
| Jay-Avnee Ltd | Professional & scientific | 2008 |
| Jayden Constructions Ltd | Construction | 2015 |
| Jayeks Ltd. | Arts & recreation | 2019 |
| Jaypri Limited | Financial services | 2012 |
| Jayson Consulting Limited | Professional & scientific | 2012 |
| JAZ Select Porsche Car Sales Limited | Wholesale & retail | 2024 |
| JAZ Specialists in ALL Things Porsche Limited | Wholesale & retail | 1994 |
| JB Wright Key Properties Ltd | Real estate | 2025 |
| JBC Design Consultants Limited | Information & communication | 2007 |
| JBG Development Limited | Construction | 2017 |
| JBR3 Limited | Real estate | 2016 |
| JBS Electrical & Properties Ltd | Construction | 2018 |
| Jbthebrand Ltd | Wholesale & retail | 2022 |
| JC & JC Ltd | Wholesale & retail | 2007 |
| JC Stanmore Limited | Administrative & support | 2020 |
| JC9 Investments Ltd | Real estate | 2020 |
| JCA Stanmore Limited | Administrative & support | 2025 |
| JCB Windows Ltd | Construction | 2022 |
| JD Risk Solutions Ltd | Administrative & support | 2019 |
| JD UK Ventures Ltd | Wholesale & retail | 2024 |
| JD2 Investments Ltd | Real estate | 2023 |
| JDM Vehicle Solutions Limited | Professional & scientific | 2024 |
| Jdmc Properties Ltd | Real estate | 2017 |
| JDR (Squirries Street) Ventures Limited | Real estate | 2017 |
| JDR Operations Limited | Real estate | 2022 |
| JED Leicester Photography Ltd | Professional & scientific | 2013 |
| Jeet Building Services Limited | Construction | 2021 |
| Jeita Restaurant Limited | Hospitality | 2021 |
| Jellicoe Properties Limited | Real estate | 2006 |
| Jellyjames Publishing Limited | Education | 2010 |
| JEM City Ltd | Wholesale & retail | 2025 |
| Jemalive Limited | Administrative & support | 1989 |
| Jemima Jasmine Ltd | Wholesale & retail | 2019 |
| Jeminy Jewel Limited | Wholesale & retail | 2026 |
| Jenga (UK) Limited | Real estate | 2014 |