| Joer Limited | Real estate | 2020 |
| Joezy Rails Limited | Professional & scientific | 2018 |
| Jofam Properties Investments Ltd | Real estate | 2021 |
| Joginder Singh Ltd | Construction | 2021 |
| Johal Trucks Ltd | Transport & logistics | 2026 |
| Johar Minhas Ltd | Wholesale & retail | 2024 |
| John Alexander Consulting Ltd | Information & communication | 2023 |
| John Bygrave Limited | Administrative & support | 2016 |
| John Harwood Properties Ltd | Real estate | 2015 |
| John Hughes Properties Ltd | Real estate | 2020 |
| John James Development Limited | Real estate | 2009 |
| John James Properties Limited | Real estate | 2024 |
| John Ormerod Design Limited | Professional & scientific | 2014 |
| John Smart Heating Ltd | Construction | 2024 |
| John Tarbox Tyres & Exhausts Limited | Wholesale & retail | 1985 |
| John Whittaker Ltd | Other services | 2013 |
| Johnfaw Group Ltd | Wholesale & retail | 2021 |
| Johnson Multi Services UK Limited | Construction | 2008 |
| Johnsons Lettings Services Ltd | Health & social care | 2025 |
| Johnsons Recruitment Ltd | Administrative & support | 2025 |
| Joil Properties Limited | Real estate | 2019 |
| Join Hands Care Ltd | Health & social care | 2019 |
| Join Hands Properties Ltd | Real estate | 2022 |
| Joint Heirs Ltd | Other services | 2022 |
| Jojofine Ltd | Other services | 2022 |
| Jokob Transportation Ltd | Construction | 2019 |
| Jomider Property Ltd | Real estate | 2023 |
| JON Bruce Consulting Limited | Administrative & support | 2014 |
| Jona Renovation Ltd | Construction | 2025 |
| Joneilz Ltd | Construction | 2024 |
| Jones Plastering Services Ltd | Other services | 2022 |
| Jonfel Cleaning Services Ltd | Administrative & support | 2022 |
| Jono Trans Ltd | Transport & logistics | 2022 |
| Jord Care Ltd | Health & social care | 2025 |
| Jordan River Ltd | Hospitality | 2024 |
| Jordiwheels Ltd | Administrative & support | 2024 |
| JOS Real Estate Limited | Construction | 2019 |
| Joseph Insulation Ltd | Construction | 2023 |
| Joseph Rochford Holdings Ltd | Agriculture & fishing | 2018 |
| Joseph Westiform UK Limited | Construction | 2024 |
| Josephine Sephton Consulting Ltd | Professional & scientific | 2026 |
| Joshi Worldwide IP Limited | Professional & scientific | 2015 |
| Joshua Donald Europe Ltd | Wholesale & retail | 2025 |
| Joshua Donald Ltd | Wholesale & retail | 2015 |
| Josif Construction Ltd | Construction | 2025 |
| JOT Fitted Wardrobes Ltd | Manufacturing | 2023 |
| Joud Footwear Ltd | Administrative & support | 2017 |
| Jovel Limited | Professional & scientific | 2007 |
| Joy R 24/7CARE Ltd | Health & social care | 2017 |
| Joy Stay Limited | Households | 2024 |
| Joynes Nash Limited | Other services | 2015 |
| Jo’S Coffee Shop & Sandwich Bar Ltd | Hospitality | 2026 |
| JP Durai Property Holding Limited | Households | 2025 |
| JP Industry Qualifications Ltd | Education | 2023 |
| JP International Examinations Limited | Education | 2010 |
| JP Move Limited | Real estate | 2024 |
| JP Roofing Solutions Ltd | Construction | 2025 |
| Jpajsl Limited | Administrative & support | 2023 |
| Jpay Ltd | Professional & scientific | 2021 |
| JPC Solar Limited | Wholesale & retail | 2006 |
| JPL Contracts Ltd | Construction | 2022 |
| Jpms Group Limited | Real estate | 2021 |
| JPR Carpentry Services Ltd | Construction | 2017 |
| JR Dasilva Promotions Limited | Arts & recreation | 2014 |
| JR Estates London Ltd | Real estate | 2024 |
| JR Outsourcing & Marketing Ltd | Administrative & support | 2023 |
| JR Pro Transport Ltd | Transport & logistics | 2020 |
| Jrcreativity CIC | Health & social care | 2025 |
| JRI Transport Ltd | Transport & logistics | 2019 |
| JRJ Sparkle Clean Ltd | Administrative & support | 2026 |
| Jrnone Limited | Real estate | 2021 |
| JRT Foods Limited | Hospitality | 2023 |
| JS Drive Ltd | Education | 2024 |
| JS Kalirai Limited | Financial services | 2011 |
| JS Properties Management Ltd | Real estate | 2025 |
| JS Sports (Luton) Limited | Wholesale & retail | 2017 |
| JSA Construction Ltd | Construction | 2026 |
| Jsap Limited | Real estate | 2025 |
| JSF Food Ltd | Hospitality | 2025 |
| Jsfs Investments Ltd | Real estate | 2022 |
| Jsiki Ltd | Administrative & support | 2025 |
| JSJ Construction Limited | Construction | 2024 |
| JSL Property Management Ltd | Real estate | 2024 |
| JSM Enterprises Limited | Construction | 1997 |
| Jsmotion Limited | Information & communication | 2024 |
| JST Highways Group Ltd | Construction | 2021 |
| JST Services Ltd | Construction | 2018 |
| JT Aphrique Limited | Wholesale & retail | 2012 |
| JT Consultancy Limited | Construction | 1996 |
| JT Lifestyle Homes Limited | Extraterritorial | 2019 |
| JTA Logistics Ltd | Transport & logistics | 2022 |
| JTG Property Ltd | Real estate | 2022 |
| JTL Electrical Ltd | Construction | 2024 |
| JTM Paving and Landscaping Ltd | Construction | 2021 |
| Jtmt Limited | Financial services | 2022 |
| JTS Inspire Property Ltd | Real estate | 2024 |
| JTS Prestige Properties Limited | Real estate | 2022 |
| Jtta Logistics Ltd | Transport & logistics | 2025 |
| Judah Harrison Limited | Real estate | 2012 |
| Juderachel Care Limited | Health & social care | 2022 |