| Jmdm Investments Ltd | Real estate | 2026 |
| JMH Technology (UK) Limited | Administrative & support | 2007 |
| JMP Plant Hire Ltd | Extraterritorial | 2019 |
| JMR Software PTY Ltd | Information & communication | 2024 |
| JMS Solutions Limited | Professional & scientific | 2022 |
| Jmsg Holdings Limited | Real estate | 2022 |
| Jmsinspection Limited | Professional & scientific | 2010 |
| JMT Car Source Limited | Administrative & support | 2019 |
| JMT Consulting Services Ltd | Financial services | 2019 |
| Jnch Properties Ltd | Real estate | 2022 |
| JO Sawkins Ltd | Extraterritorial | 2024 |
| JO Wade Limited | Administrative & support | 2012 |
| Joanna Brown Consulting Ltd | Professional & scientific | 2023 |
| Joanne Markham Ltd | Hospitality | 2026 |
| Joel-Lee Groundworks Ltd | Construction | 2018 |
| Joeymullins Ltd | Manufacturing | 2017 |
| John & Paul Limited | Real estate | 2004 |
| John Build Limited | Construction | 2025 |
| John Copp Pebbledashing Ltd | Construction | 2016 |
| John Inkster Limited | Wholesale & retail | 1959 |
| John Winters Civil Engineering Ltd | Construction | 2014 |
| JOHNHEATHER1 Ltd | Construction | 2024 |
| Johnson Interiors Fitted Furniture Ltd | Manufacturing | 2024 |
| Joint Sales Solutions Ltd. | Wholesale & retail | 2019 |
| Jointed Veneers Limited | Manufacturing | 1988 |
| JOJOSTORES22 Limited | Wholesale & retail | 2025 |
| JON Clayden Construction Management Limited | Professional & scientific | 2024 |
| JON Coote Limited | Professional & scientific | 1999 |
| JON Paul Ladd Limited | Professional & scientific | 2018 |
| Jones-Holloway Capital Ltd | Real estate | 2020 |
| Joopiter Limited | Professional & scientific | 2014 |
| Jose Electrical Ltd | Construction | 2025 |
| Joseph Quinn Ltd | Wholesale & retail | 2024 |
| Joshua King Creative Studios Ltd | Professional & scientific | 2025 |
| Joy Brown Property Ltd | Real estate | 2022 |
| Joy’S Catering Ltd | Hospitality | 2023 |
| JP Construction (Brentwood) Ltd | Construction | 2015 |
| JP Industry Limited | Manufacturing | 2025 |
| JPS Cladding Ltd | Construction | 2026 |
| JRG Communications Limited | Professional & scientific | 2014 |
| JRG Medical Aesthetics Limited | Health & social care | 2021 |
| JRW Automotive Limited | Wholesale & retail | 2024 |
| JS Fusion Fabrication Ltd | Construction | 2024 |
| JS Glass Ltd | Construction | 2019 |
| JSB Construction (South East) Ltd | Construction | 2021 |
| JSB Vehicle Solutions Ltd | Wholesale & retail | 2025 |
| JSC Consultants Ltd | Construction | 2024 |
| JSJ Properties Limited | Real estate | 2000 |
| JSM Prestige Motors Ltd | Wholesale & retail | 2018 |
| JST Windows & Doors Ltd | Construction | 2021 |
| JSW Autoworks Limited | Wholesale & retail | 2026 |
| JT Holding Group Limited | Administrative & support | 2017 |
| JTB Functional Fitness Limited | Arts & recreation | 2018 |
| JTB Socials Ltd | Professional & scientific | 2023 |
| Jtlb Functional Fitness Limited | Arts & recreation | 2017 |
| Jubilat Advisory Ltd | Financial services | 2025 |
| Jubilee Stud Farm Limited | Construction | 2020 |
| Judith Ekblom Ltd | Manufacturing | 2016 |
| Juli Ltd | Other services | 2015 |
| Julian Christian Limited | Manufacturing | 2001 |
| Julian Nathan Limited | Wholesale & retail | 2016 |
| Jump Thought Ltd | Information & communication | 2021 |
| JUN JAB Ltd | Wholesale & retail | 2026 |
| Junction House Freehold Ltd | Households | 2026 |
| Jusrose Ltd | Education | 2020 |
| Just Draft Limited | Information & communication | 2025 |
| Just Party Limited | Wholesale & retail | 2001 |
| Jutland Jack Film Ltd | Information & communication | 2021 |
| Juvenus Limited | Professional & scientific | 2014 |
| Juvenus Performance Limited | Wholesale & retail | 2020 |
| JVR Electrical Solutions Limited | Construction | 2010 |
| JW Braidwood Limited | Administrative & support | 2013 |
| JW English Consultancy Ltd | Public administration | 2006 |
| JW Property Partners Limited | Real estate | 2025 |
| JWB Digital Product Limited | Information & communication | 2026 |
| JWC Building Services Ltd | Construction | 2024 |
| JWD Heating & Plumbing Services Ltd | Construction | 2020 |
| JWE Consultants Ltd | Other services | 2019 |
| Jwpire Limited | Real estate | 2020 |
| JXY Investments Limited | Real estate | 2023 |
| K & a Car Sales Ltd | Wholesale & retail | 2025 |
| K a Hedges Building and Roofing Contractors Ltd | Administrative & support | 2010 |
| K B Fitness Limited | Arts & recreation | 2006 |
| K Barrett Media Ltd | Professional & scientific | 2008 |
| K C Systems Ltd | Administrative & support | 2022 |
| K H Petkov Limited | Transport & logistics | 2019 |
| K O Investments Limited | Other services | 2004 |
| K&K Consulting Limited | Professional & scientific | 2003 |
| K.I.T. Carpentry Limited | Construction | 2005 |
| K.J. Orthodontic Therapy Ltd | Health & social care | 2019 |
| K1W1 Consulting Limited | Professional & scientific | 2022 |
| Kafeero Limited | Health & social care | 2012 |
| KAH Scaffolding Limited | Construction | 2019 |
| Kahm Property Development Ltd | Construction | 2023 |
| Kaiandtaisthaifood Ltd | Hospitality | 2026 |
| Kairos Estates Ltd | Real estate | 2019 |
| Kaitech Consultants Limited | Construction | 2011 |
| KAJ Consultancy Services Ltd | Administrative & support | 2016 |
| Kajo Solutions Ltd | Information & communication | 2025 |
| Kaleidoscope Commerce Limited | Administrative & support | 2000 |