| Jallen Gourmet Ltd | Manufacturing | 2019 |
| JAM Sutton Studio Ltd | Arts & recreation | 2014 |
| James Alexander Financial Services Ltd. | Financial services | 2014 |
| James Alexander Investments | Financial services | 2017 |
| James and Bacchus Associates Ltd | Professional & scientific | 2022 |
| James Civil Engineering Limited | Construction | 2015 |
| James Hirons | Health & social care | 2014 |
| James-Greyling Holdings Ltd | Financial services | 2025 |
| James-Greyling Ltd | Information & communication | 2021 |
| Jamestaylor Designer Clothing Ltd | Wholesale & retail | 2024 |
| Jamestaylor Holdings Ltd | Real estate | 2021 |
| Jamie Ward Furniture Limited | Manufacturing | 2022 |
| JAN Barber Limited | Other services | 2025 |
| Jandu Property Solutions Limited | Real estate | 2019 |
| Jandu Solutions Limited | Information & communication | 2016 |
| Jani Vaidik Services Ltd | Other services | 2023 |
| Jarrett Property Holdings Limited | Real estate | 2023 |
| Jarvis Management Limited | Information & communication | 2010 |
| Jasim Property Ltd | Real estate | 2019 |
| JAT Estates Limited | Real estate | 2004 |
| Jata Group Limited | Financial services | 2026 |
| Jata Properties Limited | Real estate | 2026 |
| Javelin Block Fidco Limited | Extraterritorial | 2025 |
| Javelin Block Holdings Limited | Financial services | 2015 |
| Javelin Block Limited | Construction | 2010 |
| Javer Ltd | Information & communication | 2024 |
| Jayc Limited | Professional & scientific | 2018 |
| Jayne Commercial Limited | Construction | 2009 |
| Jayne Homes (Husbands Bosworth) Limited | Extraterritorial | 2017 |
| JAZ Nannar Consulting Ltd | Professional & scientific | 2019 |
| Jazzman Records Limited | Wholesale & retail | 2002 |
| JB Doors and Windows Limited | Construction | 2020 |
| JB Housing Solutions Ltd | Real estate | 2020 |
| JBD Home Stores Ltd | Wholesale & retail | 2026 |
| JBM Construction (UK) Limited | Construction | 2013 |
| JCS Mechanical Services Ltd | Wholesale & retail | 2025 |
| JD Elite Fire Doors Limited | Construction | 2024 |
| JD Properties Investments Limited | Households | 2016 |
| JDE Enterprises Ltd | Real estate | 2016 |
| JDJ Pratt Properties Limited | Real estate | 2022 |
| JDM Express Ltd | Wholesale & retail | 2014 |
| Jdmk Construction Limited | Professional & scientific | 2016 |
| JDS Groundworks & Civil Engineering Ltd | Construction | 2025 |
| Jedi Deansgate Limited | Hospitality | 2020 |
| Jelly Film Ltd | Information & communication | 2019 |
| Jenkins & Tate Entertainment Limited | Information & communication | 2020 |
| Jenks ENG Ltd | Information & communication | 2026 |
| Jenny Waggott Ltd | Arts & recreation | 2003 |
| Jephson & Greatheed Limited | Transport & logistics | 2026 |
| Jephson Court Management Company Ltd | Real estate | 2019 |
| Jephson Design Ltd | Information & communication | 2026 |
| Jephson Place Management Company Limited | Administrative & support | 1982 |
| Jeremy LIM Architect Ltd | Professional & scientific | 2003 |
| Jersey Villa Property Company Ltd | Real estate | 2026 |
| Jesse Stokes Limited | Real estate | 2012 |
| Jessie Crowther & Co Ltd | Real estate | 2025 |
| JET 2 Clear Limited | Administrative & support | 2025 |
| JETS4UDIRECT Limited | Wholesale & retail | 2013 |
| Jetskills Ltd | Transport & logistics | 2023 |
| JF Advanced Technology Solutions Ltd | Professional & scientific | 2019 |
| Jfkapital Ltd | Financial services | 2024 |
| JH Events Entertainment Ltd | Arts & recreation | 2021 |
| JH Property Consultants Limited | Real estate | 2013 |
| Jhgproperties Limited | Real estate | 2008 |
| Jhodder Design Ltd | Professional & scientific | 2023 |
| JIM Doran Hand Controls Limited | Wholesale & retail | 2010 |
| JJ Francis Consultancy Limited | Wholesale & retail | 2020 |
| Jjdc Limited | Administrative & support | 2014 |
| JJH Paintwork Limited | Construction | 2023 |
| JJS Electrical Limited | Professional & scientific | 2021 |
| JJV Property Group Ltd | Real estate | 2023 |
| JK Analytics Limited | Education | 2021 |
| JK Metal Fabrications Ltd | Manufacturing | 2020 |
| JKB 99 Properties Ltd | Wholesale & retail | 2021 |
| JKL Prescribing Ltd | Health & social care | 2022 |
| JKR Consulting Ltd | Information & communication | 2021 |
| JKR Trading Co. Limited | Professional & scientific | 2022 |
| JL Electrical Warwickshire Limited | Construction | 2007 |
| JL Surveys Limited | Professional & scientific | 2021 |
| Jlfcreates Ltd | Professional & scientific | 2026 |
| JLM + Co Design Ltd. | Professional & scientific | 2024 |
| Jlms Group Ltd | Construction | 2026 |
| JLR Servicenow Solutions Limited | Professional & scientific | 2021 |
| JM Mental Health Ltd | Health & social care | 2017 |
| JM Property Solutions Limited | Administrative & support | 2012 |
| JMB Estimating Ltd | Construction | 2022 |
| JMB Research Limited | Professional & scientific | 2014 |
| JMD Investments & Estates Limited | Professional & scientific | 2018 |
| JMD Land & Property Limited | Professional & scientific | 2020 |
| JMD Manchester Ltd | Professional & scientific | 2021 |
| Jmih Management Ltd | Administrative & support | 2015 |
| JMM Trading (Midlands) Limited | Wholesale & retail | 2024 |
| JMM Venues (JQ) Limited | Hospitality | 2024 |
| JMO Ventures Ltd | Wholesale & retail | 2023 |
| JMS 5STAR Limited | Wholesale & retail | 2023 |
| JMW Consulting (Finance) Ltd | Professional & scientific | 2025 |
| JO Cantle Coaching Limited | Administrative & support | 2008 |
| Joanne Lally & Partners Ltd | Administrative & support | 2017 |
| Joblingo Ltd | Administrative & support | 2025 |
| Jobs Behind the Scenes Ltd | Administrative & support | 2008 |