| JB Fitness Hybrid Gym Ltd | Arts & recreation | 2026 |
| JBD UK Holdings Ltd | Real estate | 2023 |
| JBF PT Ltd | Arts & recreation | 2026 |
| JBI Management Services Ltd | Professional & scientific | 2023 |
| Jbprm Ltd | Wholesale & retail | 2018 |
| JBR Holdings Ltd | Real estate | 2019 |
| JBW Digital Limited | Professional & scientific | 2024 |
| JC Dentures Ltd | Manufacturing | 2024 |
| Jcho Holdings Ltd | Financial services | 2026 |
| JCL Transport UK Ltd | Transport & logistics | 2024 |
| Jcla Transport UK Limited | Transport & logistics | 2025 |
| JCW Engineering Solutions Limited | Manufacturing | 2017 |
| JD Transport Group Ltd | Manufacturing | 2025 |
| JDH & SON Limited | Professional & scientific | 2014 |
| Jdmn Telecommunications Ltd | Information & communication | 2024 |
| Jdns Vending Ltd | Wholesale & retail | 2022 |
| Jdsd Construction Ltd | Construction | 2024 |
| Jecla Ltd | Real estate | 2020 |
| Jeffrey Rose Limited | Professional & scientific | 2016 |
| Jemed Ltd | Agriculture & fishing | 2025 |
| Jemial Properties Ltd | Real estate | 2025 |
| JEN Goodman Properties Limited | Real estate | 2016 |
| Jenson Country Homes Ltd | Construction | 2021 |
| Jenssen Consulting Ltd | Professional & scientific | 2023 |
| Jenuine Consulting Ltd | Professional & scientific | 2015 |
| Jeremy Blatherwick Limited | Professional & scientific | 2009 |
| Jeremy Kitchin Practice M & a Ltd | Professional & scientific | 2000 |
| Jermyn & Dunn Properties Limited | Real estate | 2013 |
| Jessop and LEE Solutions Limited | Professional & scientific | 2025 |
| Jetpac AB Ltd | Professional & scientific | 2026 |
| Jewel Care Services Limited | Health & social care | 2026 |
| Jewl Theatre Ltd | Arts & recreation | 2025 |
| JFA Services Limited | Construction | 2016 |
| JG Equestrian Ltd | Agriculture & fishing | 2024 |
| JGA Enterprises Limited | Information & communication | 2016 |
| Jgow Services Limited | Wholesale & retail | 2020 |
| Jhankey Ltd | Construction | 2018 |
| JID Medicals Limited | Health & social care | 2023 |
| Jill Asher Limited | Administrative & support | 2003 |
| JIT Consultancy Services Limited | Information & communication | 2018 |
| JJ40 Limited | Real estate | 2013 |
| JJC Contractors Ltd | Construction | 2013 |
| JKR Property Group Ltd | Real estate | 2024 |
| JL Business Services Limited | Professional & scientific | 2019 |
| JL Crane Hire Ltd | Administrative & support | 2020 |
| JL Haulage Ltd | Transport & logistics | 2023 |
| JLA Housing Limited | Real estate | 2022 |
| JLH Property Consultants Limited | Real estate | 2023 |
| JLL Services Limited | Professional & scientific | 2004 |
| JM Financial Consultancy Limited | Financial services | 2017 |
| JM Szybiak Ltd | Transport & logistics | 2019 |
| JMC Setting OUT Ltd | Administrative & support | 2014 |
| Jmdsupply Ltd | Wholesale & retail | 2026 |
| JME Home Improvements Ltd | Professional & scientific | 2022 |
| JNM Coaching Limited | Arts & recreation | 2022 |
| JO Gordon Consulting Ltd | Information & communication | 2018 |
| Joecharis Caring Service Ltd | Administrative & support | 2017 |
| JOH Design Ltd | Professional & scientific | 2019 |
| John a LEE Consultancy Ltd | Professional & scientific | 2010 |
| John Burnett Limited | Financial services | 1988 |
| John Day Electrical Limited | Manufacturing | 1983 |
| John Dunstan Limited | Professional & scientific | 2008 |
| John Ellis & Associates Limited | Professional & scientific | 2015 |
| John Harris Software Limited | Information & communication | 2018 |
| John R. Wright Limited | Agriculture & fishing | 1973 |
| John Usher Building Contractor Limited | Construction | 2003 |
| Johnson Earthworks & Plant Hire Ltd | Construction | 2018 |
| Johnson Electrical Solutions Ltd. | Construction | 2013 |
| Joji Films Ltd | Information & communication | 2019 |
| Jojolopa Ltd | Hospitality | 2024 |
| JOLLYBOBS@NO.194 Ltd | Hospitality | 2020 |
| JON Brambles (Newark) Limited | Real estate | 2003 |
| JON Brambles Estate Agents Limited | Extraterritorial | 2016 |
| JON Brambles Letting Agents Limited | Real estate | 2016 |
| JON Wall Fisheries Limited | Agriculture & fishing | 2000 |
| JON Yarwood Print & Copy Consulting Limited | Administrative & support | 2013 |
| Jonathan Allen Price Limited | Information & communication | 2024 |
| Jonathan Evans Neurology Limited | Health & social care | 2021 |
| Jonathan Metcalfe Architecture Ltd | Construction | 2021 |
| Jones Maintenance Solutions Ltd | Construction | 2010 |
| Jones Safety & Risk Management Ltd | Administrative & support | 2018 |
| Jonesy Safety Services Ltd | Public administration | 2024 |
| Jonic Building Services Limited | Construction | 2005 |
| Jonsu Limited | Wholesale & retail | 2011 |
| Jonty AI | | 2026 |
| Jooper Itsm (Claypole) Limited | Information & communication | 2023 |
| Jordan Ptrs Ltd | Professional & scientific | 2004 |
| Jordan Road Surfacing Limited | Construction | 2002 |
| JOS Mixers UK Limited | Manufacturing | 2020 |
| Jose Estates Ltd | Real estate | 2021 |
| JOW Care Group Limited | Health & social care | 2026 |
| Joy's African and Caribbean Food Shop Ltd | Wholesale & retail | 2024 |
| Joynes Estates Limited | Real estate | 2019 |
| JP Business Services Limited | Administrative & support | 2022 |
| Jpak Consultancy Ltd | Information & communication | 2024 |
| JPG Creates Limited | Wholesale & retail | 2019 |
| JRB Property Development Ltd | Households | 2023 |
| JRC Housing Limited | Real estate | 2020 |
| JRC Welding Services Ltd | Manufacturing | 2025 |
| JS &VA Properties Ltd | Real estate | 2015 |