| John Puttick Associates Limited | Professional & scientific | 2014 |
| John Simon Hair Specialists Limited | Other services | 2020 |
| John Simon Salons Limited | Other services | 2003 |
| John Strand MK Ltd | Wholesale & retail | 1997 |
| Johnemoto Ltd | Information & communication | 2017 |
| Johntee Event Organisers Limited | Information & communication | 2016 |
| Jojo Films Limited | Arts & recreation | 2018 |
| Jojoba Management Limited | Professional & scientific | 2018 |
| Jolene Sher Ltd | Health & social care | 2011 |
| Jolimoon Ltd | Health & social care | 2026 |
| Jolly Ideal Homes Ltd | Real estate | 2025 |
| Jolly Time Nursery Limited | Education | 2015 |
| Jomaa Medical Services Limited | Health & social care | 2021 |
| Jomansa Limited | Real estate | 2017 |
| Jomansa PS Ltd | Real estate | 2023 |
| Jomoj Ltd | Professional & scientific | 2024 |
| JON Brick Work Limited | Construction | 2023 |
| JON Landscaping Ltd | Construction | 2024 |
| JON Phillips Consultancy Limited | Professional & scientific | 2021 |
| Jona Studios Limited | Information & communication | 2023 |
| Jonathan Teper Consulting Limited | Information & communication | 2007 |
| Jonbee Limited | Professional & scientific | 2012 |
| Jonny Searle Consulting Ltd | Professional & scientific | 2016 |
| Joodd Limited | Wholesale & retail | 2020 |
| Jord by Nord Ltd | Hospitality | 2023 |
| Jordan Practice Ltd | Health & social care | 2011 |
| Jordan Waid Limited | Administrative & support | 2019 |
| Joseph & Co Consulting Limited | Administrative & support | 2015 |
| Joseph & Co Residential Ltd | Real estate | 2020 |
| Joseph Glass Magic Ltd | Arts & recreation | 2022 |
| Joseph Scott Holdings Ltd | Financial services | 2025 |
| Joseph Scott Lettings Ltd | Real estate | 2013 |
| Joseph Scott Prime Ltd | Real estate | 2025 |
| Joseph Scott Sales Ltd | Real estate | 2025 |
| Joseph Scotton Engineering Limited | Professional & scientific | 2022 |
| Josh & ETH Limited | Wholesale & retail | 2017 |
| Josh Rosenberg Consultancy Limited | Other services | 2016 |
| Joshi Homes Limited | Real estate | 2015 |
| Joshi Innovations Ltd | Manufacturing | 2025 |
| Josi's Corner Ltd | Arts & recreation | 2021 |
| Jothin Greetings Ltd | Wholesale & retail | 2024 |
| Journalist Support Committee | Other services | 2018 |
| Journey Solutions Limited | Wholesale & retail | 2025 |
| Joy and Kindness Ltd | Hospitality | 2023 |
| Joy Refurbishment UK Ltd | Construction | 2024 |
| JP Electric Ltd | Construction | 2015 |
| JP Healthcare Limited | Health & social care | 2021 |
| JP Healthwise Limited | Health & social care | 2011 |
| JPF Film and TV Services Limited | Information & communication | 2010 |
| JPM London Ltd | Construction | 2016 |
| JPW Controls Limited | Professional & scientific | 2026 |
| JR Antala Limited | Transport & logistics | 2024 |
| JR Art International Ltd | Wholesale & retail | 2020 |
| JR Consulting Solutions Limited | Professional & scientific | 2020 |
| JR Deal Advisory Limited | Professional & scientific | 2020 |
| JR Invest Hub Ltd | Administrative & support | 2017 |
| JR Investment Management Limited | Professional & scientific | 2010 |
| JR Mckenzie Real Estate Limited | Real estate | 2021 |
| JR Wealth Ltd | Professional & scientific | 2019 |
| JRD Homes Development 2 Ltd | Real estate | 2026 |
| JRD Homes Development Ltd | Real estate | 2025 |
| JRD Music Ltd | Arts & recreation | 2018 |
| JS Auto Ltd | Wholesale & retail | 2026 |
| Js&Js Properties Ltd | Real estate | 2024 |
| JSB SAI Limited | Financial services | 2016 |
| Jsdd Property Ltd | Real estate | 2022 |
| JSK Holdings Ventures Ltd | | 2023 |
| JSM Property Holdings Ltd | Real estate | 2024 |
| JSN Investment Limited | Real estate | 2016 |
| JSR13 Investments Limited | Real estate | 2026 |
| JTM Trader Limited | Wholesale & retail | 2016 |
| JTN Associates Limited | Professional & scientific | 2023 |
| JTR Services Limited | Real estate | 2009 |
| Jtse Project Services Limited | Administrative & support | 2011 |
| JTY Clothing Ltd | Wholesale & retail | 2026 |
| Juan KP Ltd | Real estate | 2025 |
| Jubilee Christian Church International (United Kingdom) | Other services | 2010 |
| Judith Moeckell Consultancy Limited | Professional & scientific | 2007 |
| Juicesayyo Ltd | Hospitality | 2026 |
| Jukalu Limited | Real estate | 2008 |
| Juke ST James 2020 Ltd | Real estate | 2020 |
| Juke ST James 3030 Ltd | Real estate | 2026 |
| Julia Kennedy Photography Limited | Professional & scientific | 2013 |
| Julianmiles Limited | Professional & scientific | 2006 |
| Julie Hair & Beauty Ltd | Other services | 2016 |
| July and ANA Limited | Transport & logistics | 2018 |
| Jump Ahead Media Limited | Information & communication | 2015 |
| Junior & Rebie Ltd | Manufacturing | 2017 |
| Juniper Conquest Ltd | Real estate | 2021 |
| Jupitas Jewellery Limited | Wholesale & retail | 2015 |
| Jurovschi Ltd | Construction | 2014 |
| Jusbefit Ltd | Other services | 2018 |
| Just Cleaned Limited | Administrative & support | 2021 |
| Just Duck Catering Ltd | Hospitality | 2026 |
| Just Leaf Ltd | Real estate | 2023 |
| Just Renovated Ltd | Construction | 2024 |
| Just Renovations Limited | Real estate | 2017 |
| Justanumber Ltd | Information & communication | 2023 |
| Justcold Ltd | Other services | 2019 |
| Justconceptdesigns Ltd | Wholesale & retail | 2024 |