| JJL Consulting Services Limited | Information & communication | 2023 |
| Jjtr Property Ltd | Real estate | 2025 |
| JJV Building Materials Ltd | Wholesale & retail | 2020 |
| JK Construction (East Anglia) Limited | Construction | 2002 |
| JK Energy Ltd | Information & communication | 2003 |
| JK Selin Propertie Limited | Real estate | 2024 |
| JK Window Shade Ltd | Construction | 2023 |
| Jk's Bargains Ltd | Wholesale & retail | 2011 |
| Jkjl Services Ltd | Professional & scientific | 2009 |
| JKS Businesses Ltd | Wholesale & retail | 2024 |
| Jksb Holding Ltd | Professional & scientific | 2022 |
| JL Property Solutions Ltd | Real estate | 2017 |
| JLF Designs Limited | Professional & scientific | 2010 |
| JLH Window Cleaning Ltd | Administrative & support | 2025 |
| JLK Data Solutions Ltd | Information & communication | 2023 |
| JLM Housing Limited | Real estate | 2024 |
| Jlrf Consulting Ltd | Public administration | 2023 |
| JM Capital Enterprise Ltd | Real estate | 2024 |
| JM Consultancy Services (Luton) Limited | Professional & scientific | 2022 |
| JM Consulting Group Ltd | Information & communication | 2026 |
| JM Lime Ltd | Wholesale & retail | 2025 |
| JM Pharma Limited | Wholesale & retail | 2025 |
| JM Quality Management Services Ltd | Professional & scientific | 2020 |
| Jmac Engineering & Design Ltd | Professional & scientific | 2024 |
| JMG Civil Engineering Ltd | Construction | 2020 |
| JMG Publishing Limited | Information & communication | 2023 |
| Jminkas Property Management &Cleaning Services Ltd | Administrative & support | 2025 |
| JMJ and Associates Ltd | Professional & scientific | 2012 |
| JMJ Environmental Limited | Professional & scientific | 2018 |
| JMJ Stores Ltd | Wholesale & retail | 2025 |
| JMK Elite Group Ltd. | Administrative & support | 2017 |
| JMX Logistics Limited | Transport & logistics | 2024 |
| JN Enterprises Ltd | Construction | 2025 |
| JNI Global Ltd | Wholesale & retail | 2025 |
| JNL Cabling Limited | Construction | 2006 |
| JNM Rosko Ltd | Wholesale & retail | 2017 |
| JO Bowen Limited | Arts & recreation | 2003 |
| JO Easy Numbers Ltd | Information & communication | 2025 |
| JO Travell Ltd | Education | 2025 |
| JOA Solutions Limited | Administrative & support | 2024 |
| Joann Shaw & Co Limited | Hospitality | 2007 |
| Jobseekers Limited | Information & communication | 2018 |
| Jockey UK Bidco Limited | Financial services | 2021 |
| Jodal Urban Ltd | Wholesale & retail | 2023 |
| Joekers X Change Ltd | Wholesale & retail | 2025 |
| Joel Holdings Ltd | Financial services | 2021 |
| Joelle Stores Limited | Wholesale & retail | 2024 |
| Joga Bonito Easingwold Ltd | Education | 2025 |
| Johannson Limited | Professional & scientific | 2011 |
| John Banks Group Holdings Limited | Wholesale & retail | 2019 |
| John Brothers Services Ltd | Other services | 2026 |
| John Carr Mountain and Medical Ltd | Education | 2010 |
| John Cutmore Builds Limited | Construction | 2002 |
| John Howell & Co Protection B Ltd | Extraterritorial | 2010 |
| John Howell & Co Protection a Ltd | Extraterritorial | 2010 |
| John Rowe and Partners Limited | Administrative & support | 2012 |
| John Stebbing Architects Limited | Professional & scientific | 2006 |
| Johnny Street Food Ltd | Hospitality | 2024 |
| Johnross Courage Ltd | Information & communication | 2013 |
| Johnryan Limited | Other services | 2019 |
| Johnson's Financial Solutions Ltd | Professional & scientific | 2024 |
| Join the Table Limited | Hospitality | 2025 |
| Joined-Up Training Limited | Professional & scientific | 2021 |
| Jolley-Jarvis Enterprises Ltd | Professional & scientific | 2017 |
| Jollystep Ltd | Wholesale & retail | 2025 |
| Jolt Capital Investments Limited | Real estate | 2025 |
| JON Mitchell Shotblasting Limited | Professional & scientific | 2018 |
| Jonal Capital Management LLP | | 2022 |
| Jonas VON Stedingk Ltd | Professional & scientific | 2025 |
| Jonathan Alan Vidler (Consulting) Limited | Professional & scientific | 2021 |
| Jonathan Mathers Holdings Limited | Financial services | 2016 |
| Jonathan Sanders Limited | Health & social care | 2009 |
| Jonathan Waters (Potatoes) Limited | Agriculture & fishing | 2005 |
| Jones Listers Limited | Wholesale & retail | 2025 |
| Jones Planning Ltd. | Professional & scientific | 2015 |
| Jones Professional Limited | Information & communication | 2022 |
| Joni Baba Ltd | Wholesale & retail | 2025 |
| Joniip Ltd | Professional & scientific | 2025 |
| Joor Limited | Professional & scientific | 2012 |
| Jordan and Cousins Ltd | Wholesale & retail | 2026 |
| Jords Plastering Ltd | Construction | 2023 |
| Jorkins Ltd | Other services | 2022 |
| Joseph Atkinson Enterprise Limited | Wholesale & retail | 2021 |
| Josie Copsey Limited | Professional & scientific | 2016 |
| Josxph Limited | Professional & scientific | 2023 |
| Jougen Ltd | Hospitality | 2022 |
| Joup Clinical Services Limited | Health & social care | 2023 |
| Journey Together TCG Ltd | Wholesale & retail | 2025 |
| Jowo Limited | Professional & scientific | 2019 |
| Joy Connection CIC | Hospitality | 2023 |
| Joy Design House Ltd | Professional & scientific | 2022 |
| Joy Ogude Ltd | Other services | 2023 |
| Joyce & Buckle Services Limited | Professional & scientific | 2004 |
| Joymat Ltd | Wholesale & retail | 2018 |
| Joynt Partners Ltd | Administrative & support | 2026 |
| Joysy Ltd | Administrative & support | 2021 |
| JP Accountants Limited | Professional & scientific | 2008 |
| JP Asset Developments Ltd | Construction | 2025 |
| JP Asset Group Ltd | Financial services | 2025 |
| JP Global Consulting Ltd | Information & communication | 2024 |