| JOE Jordan Consulting Limited | Professional & scientific | 2021 |
| JOE Mckie Limited | Information & communication | 2014 |
| JOE Public Advertising Limited | Professional & scientific | 1997 |
| Joel Doohan Limited | Construction | 2015 |
| Joel Hurst Electrical Services Ltd | Construction | 2017 |
| Joeshoba Limited | Health & social care | 2019 |
| Johanel Ltd | Financial services | 2023 |
| John D Wood & Co. Limited | Professional & scientific | 1986 |
| John Deere Forestry Limited | Agriculture & fishing | 1988 |
| John Fogarty Tsco Limited | Administrative & support | 2015 |
| John Frances Limited | Professional & scientific | 2007 |
| John Francis (Wales) Limited | Professional & scientific | 1999 |
| John Grundy (Labels) Limited | Real estate | 1951 |
| John Harrison (Sports) Limited | Wholesale & retail | 2002 |
| John Ireland's House Management Company Limited | Households | 1996 |
| John Kinghorn Ltd | Construction | 2006 |
| John Lowe Property Limited | Real estate | 2024 |
| John N Hilditch (Lettings) Limited | Real estate | 2002 |
| John Samuel Health Care Ltd | Health & social care | 2016 |
| John Sheppard & Co. Ltd. | Professional & scientific | 2002 |
| John Warburton Communications & Public Relations Ltd | Professional & scientific | 2012 |
| John Williams Electrical Limited | Construction | 2017 |
| John Wood Architect Limited | Professional & scientific | 2020 |
| Johnson Design (UK) Limited | Administrative & support | 2000 |
| Johnston Test Services Limited | Professional & scientific | 2026 |
| Jolly's Kafe Ltd | Hospitality | 2018 |
| Jollys Kafe Chaddesden Ltd | Hospitality | 2025 |
| Jomi Enterprise Ltd | Real estate | 2021 |
| Jomini Ltd | Households | 2021 |
| JON Mail Solicitors & Co Limited | Professional & scientific | 2011 |
| Jones Lang Lasalle Americas Limited | Financial services | 2025 |
| Joneston Limited | Real estate | 1988 |
| Jooi Engineering Limited | Professional & scientific | 2022 |
| Jordan Derby Limited | Financial services | 2025 |
| Jordan Kennedy 2 Limited | Financial services | 2026 |
| Jordan Kennedy Limited | Financial services | 2024 |
| Jordan-Mcqueen Limited | Administrative & support | 2018 |
| JOS Civil Infrastructure Limited | Professional & scientific | 2019 |
| JOS Solutions Limited | Professional & scientific | 2025 |
| Jose for Hair Limited | Other services | 2002 |
| Joseph & Co. Consultancy Ltd | Health & social care | 2025 |
| Joseph Abadi-Johns Ltd | Wholesale & retail | 2026 |
| Jouan Limited | Professional & scientific | 1985 |
| Jovenco Property Limited | Construction | 2015 |
| Joy Wanolus Design Limited | Professional & scientific | 2017 |
| Joyce-O'Keeffe Properties Ltd | Real estate | 2016 |
| Joyun Limited | Information & communication | 2023 |
| JP Software Limited | Professional & scientific | 2016 |
| JP Teck Ltd | Information & communication | 2024 |
| JP4LIFE Ltd | Financial services | 2012 |
| JP4LIFE Properties Ltd | Households | 2019 |
| JPB Direct Ltd | Information & communication | 2018 |
| JPD Consultants Limited | Professional & scientific | 2023 |
| Jplhg Ltd | Financial services | 2025 |
| JPM Collectables Limited | Wholesale & retail | 2024 |
| JPS Accommodation Limited | Hospitality | 2024 |
| JR Aesthetic Medicine Ltd | Health & social care | 2024 |
| JR Transformation Ltd | Professional & scientific | 2026 |
| JRA (Northern) Limited | Hospitality | 2011 |
| JRA Homes Ltd | Real estate | 2020 |
| Jrandco Limited | Professional & scientific | 2024 |
| JRB Property Cheshire Ltd | Real estate | 2024 |
| JRG Capital Group Ltd | Financial services | 2024 |
| Jrla Limited | Financial services | 2014 |
| Jrlf Communications Limited | Professional & scientific | 2021 |
| JS Comms Limited | Information & communication | 2015 |
| JS Water Management Ltd | Professional & scientific | 2019 |
| JSB Accounting Limited | Professional & scientific | 2022 |
| Jsgs Property Limited | Real estate | 2020 |
| JSH Property Consulting Limited | Professional & scientific | 2024 |
| JSL Property Investments Limited | Financial services | 2016 |
| JSM Recruitment Limited | Administrative & support | 2019 |
| Jsmurph Limited | Administrative & support | 2012 |
| Jsnr Limited | Real estate | 2007 |
| Jspb Property Management Limited | Real estate | 2017 |
| JSR Change Limited | Administrative & support | 2024 |
| JSS Education & Childcare LLP | | 2023 |
| Jstp Services Limited | Professional & scientific | 2021 |
| JT Booth Hire Limited | Administrative & support | 2025 |
| JT Clinical Systems Consultancy Limited | Professional & scientific | 2021 |
| JT Family Safeguarding Limited | Administrative & support | 2023 |
| Jtek Limited | Professional & scientific | 2022 |
| JTL Associates Ltd | Professional & scientific | 2019 |
| Jtlec-Solutions Limited | Professional & scientific | 2021 |
| JTS Environmental Services Limited | Information & communication | 2018 |
| JTS Solicitors Ltd | Professional & scientific | 2018 |
| Jtth Limited | Information & communication | 2025 |
| JTV Manchester Ltd | Wholesale & retail | 2024 |
| Jubilee 8 Ltd | Real estate | 2020 |
| Jubilee POP Consulting Limited | Administrative & support | 2015 |
| Juggler Services Limited | Information & communication | 2017 |
| Juice Nurseries Limited | Health & social care | 2006 |
| Juicebox UK Limited | Information & communication | 2026 |
| Julia Yates Training Ltd | Education | 2026 |
| Julie Saunders Consulting Ltd | Professional & scientific | 2008 |
| Jumbo Self Storage Ltd. | Transport & logistics | 2003 |
| Junior Trader CIC | Education | 2025 |
| Juniper Holdings Limited | Financial services | 2001 |
| Juniper Manton Limited | Information & communication | 2007 |
| Juno Consulting Services Ltd | Information & communication | 2020 |