| Jewish Literary Foundation | Education | 1986 |
| JF Auto Ltd | Wholesale & retail | 2023 |
| JF Collection Services Limited | Administrative & support | 2014 |
| JF Production Consultancy Limited | Professional & scientific | 2019 |
| Jfkhane Ltd | Wholesale & retail | 2018 |
| JFW Rail Limited | Construction | 2018 |
| JGA Construction and Developments Ltd. | Construction | 2020 |
| JGA Construction Works Ltd | Administrative & support | 2021 |
| JGA Developments Ltd | Construction | 2015 |
| JGL Enterprises Ltd | Wholesale & retail | 2021 |
| JGM Installations Ltd | Manufacturing | 2022 |
| JHA Party Wall Surveyors Ltd | Professional & scientific | 2023 |
| JHS Tabula Rasa Ltd | Professional & scientific | 2024 |
| JHT Pipe Installations Limited | Administrative & support | 2016 |
| JIG Carpentry Ltd | Administrative & support | 2021 |
| JIM Campbell Ltd | Information & communication | 2021 |
| Jimmy Little Ltd | Administrative & support | 2024 |
| JJ Co Properties Limited | Real estate | 2024 |
| JJ Freshway Food & Drink Limited | Hospitality | 2018 |
| JJ Property Management Services Limited | Real estate | 2020 |
| Jjgs Properties Limited | Real estate | 2019 |
| Jjpd Elite ED Ltd | Education | 2022 |
| Jjpd Group Ltd | Construction | 2020 |
| Jjpd MED Ltd | Wholesale & retail | 2021 |
| JJS Air Conditioning Limited | Construction | 2015 |
| JK Food Services Ltd | Hospitality | 2024 |
| JKA Damp Proofing & Plastering Limited | Construction | 2018 |
| JKL Brami Ltd | Real estate | 2021 |
| JKL Trade Ltd | Wholesale & retail | 2023 |
| JKR Fencing and Landscaping Limited | Administrative & support | 2025 |
| JKW Solutions Limited | Administrative & support | 2016 |
| JL Compliance Consultants Limited | Professional & scientific | 2018 |
| JLP Fitness Limited | Arts & recreation | 2023 |
| JLT Cleaning Services Ltd | Administrative & support | 2025 |
| JM 3791 Limited | Real estate | 2025 |
| JM Boards Ltd | Other services | 2025 |
| JM Carpentry Solutions Ltd | Construction | 2017 |
| JM Davies Associates Ltd | Other services | 2019 |
| JM Hancock Limited | Information & communication | 2023 |
| JM Property Management Services Ltd | Households | 2024 |
| JMB Contractors Limited | Construction | 2007 |
| JMG Natural Beauty Limited | Administrative & support | 2021 |
| JMO Marketing Limited | Professional & scientific | 2025 |
| Jmoworks Ltd | Administrative & support | 2024 |
| JMR Contracting Services Ltd | Construction | 2018 |
| JMR Roofing and Property Services Limited | Construction | 2009 |
| JMT Services Ltd | Administrative & support | 2021 |
| JMW Production Limited | Professional & scientific | 2019 |
| JNA 11 Ltd | Information & communication | 2026 |
| Joan Allen (Holdings) Limited | Professional & scientific | 2010 |
| Joanna Kabbani Ltd | Administrative & support | 2023 |
| Joanna's Hair and Beauty Salon Limited | Other services | 2021 |
| Jobasa Studios Ltd | Other services | 2016 |
| JOE the Lion Ltd | Professional & scientific | 2019 |
| Joeljay Ltd | Health & social care | 2026 |
| Jogar Ltd | Professional & scientific | 2018 |
| John Eagles Media Limited | Information & communication | 2023 |
| John Hooton Carpentry & Joinery Limited | Construction | 2014 |
| John Hooton Carpentry Limited | Construction | 2026 |
| John Mcfarland Consulting Limited | Administrative & support | 2007 |
| John Pilling Ltd. | Health & social care | 2010 |
| John Reid T/A Sheeba Frances Ltd | Professional & scientific | 2023 |
| Johnson Family Holdings Limited | Financial services | 2024 |
| Johnson's (SJ) Property Limited | Real estate | 2024 |
| Joint Joinery Limited | Manufacturing | 2008 |
| Jojan Group Limited | Wholesale & retail | 2023 |
| Jojoes Hair and Beauty Salon Limited | Other services | 2010 |
| Joker's Pack Productions Ltd | Information & communication | 2012 |
| Jolie Music Ltd | Education | 2024 |
| JON Panayi Design Production Limited | Professional & scientific | 2018 |
| Jonathan Pearce Management Consultancy Limited | Professional & scientific | 2018 |
| Jonfico Holdings Ltd | Manufacturing | 2019 |
| Jordan Taxi Services Limited | Transport & logistics | 2017 |
| Jordans Sports Grounds Solutions Limited | Arts & recreation | 2013 |
| Josh Holdings Limited | Financial services | 2015 |
| Joujou Papillon Ltd | Education | 2015 |
| Joy 4 Living Consulting Limited | Administrative & support | 2019 |
| Joyce Dawson Fish N Chips Limited | Hospitality | 2019 |
| JP Heavy Engineering Ltd | Wholesale & retail | 2025 |
| JP Morleys Ltd | Hospitality | 2024 |
| JPR Partnerships Ltd | Professional & scientific | 2025 |
| JPS London Limited | Real estate | 2023 |
| JPS Property Maintenance Limited | Administrative & support | 2015 |
| JR Hillman Limited | Households | 2020 |
| Jrmd Project Management Limited | Administrative & support | 2015 |
| JRT Carpentry Ltd | Construction | 2025 |
| JS Family Retail Ltd | Wholesale & retail | 2024 |
| JS Inspection & Equipment Services Ltd | Professional & scientific | 2021 |
| Jsandford Limited | Professional & scientific | 2018 |
| JSB Professional Cleaning Services Ltd | Administrative & support | 2026 |
| JT Grab Services Limited | Administrative & support | 2015 |
| JT Stone Restoration Ltd | Manufacturing | 2025 |
| Jtmt Property Limited | Real estate | 2026 |
| Jukes Enterprises Ltd | Real estate | 2018 |
| Julian Grant Holdings Limited | Administrative & support | 2011 |
| Julian Grant Limited | Construction | 1983 |
| Julian Grant Properties Limited | Administrative & support | 2011 |
| Junk GUY Rubbish Removal Limited | Water & waste | 2023 |
| Jupiter Properties and Investments Limited | Real estate | 2014 |
| Just Therapy Limited | Other services | 2015 |