| JDZ Media Limited | Information & communication | 2003 |
| JE & JO Ltd | Health & social care | 2021 |
| JE Manor Limited | Professional & scientific | 2011 |
| JE Tebbs Ltd | Real estate | 2024 |
| JE4 Limited | Real estate | 2016 |
| JE4 Property Investments Ltd | Real estate | 2023 |
| JEAN1MAGE Ltd | Wholesale & retail | 2025 |
| Jeanne Fairbrother Associates Limited | Health & social care | 2019 |
| Jeansalem Ltd | Real estate | 2025 |
| Jeansville Limited | Real estate | 2017 |
| Jebecanie Holdings Ltd | Financial services | 2017 |
| Jebp Developments Limited | Construction | 2017 |
| JEC NVG Ltd | Administrative & support | 2026 |
| Jeera Churwell Ltd | Hospitality | 2025 |
| Jeera Spice Ltd | Hospitality | 2015 |
| Jefe's Grilled Ltd | Hospitality | 2025 |
| Jeff Gale Ltd | Professional & scientific | 2021 |
| Jeff J Cars Limited | Administrative & support | 2025 |
| Jeff Skinner Skip Hire Limited | Water & waste | 2006 |
| Jeffers and Belgrave Ltd | Construction | 2019 |
| Jefferson Power Projects Ltd | Construction | 2025 |
| Jeffnat Healthcare Ltd | Other services | 2019 |
| Jeffreyyu Ltd | Transport & logistics | 2026 |
| Jeffs Holdings Ltd | Health & social care | 2025 |
| JEG Project Solutions Limited | Professional & scientific | 2014 |
| JEG Property Holdings Ltd | Construction | 2025 |
| Jehangiri Investments Limited | Hospitality | 2013 |
| Jehangiri Properties Ltd | Real estate | 2019 |
| Jeje Properties Ltd | Real estate | 2026 |
| JEL Psychology Limited | Professional & scientific | 2014 |
| Jeleel Oyebode Limited | Administrative & support | 2020 |
| Jelenke Properties Ltd | Real estate | 2023 |
| Jellyshay Distribution Ltd | Wholesale & retail | 2026 |
| Jelstones Ltd | Real estate | 2022 |
| JEM Impact and Engagement Consultants Ltd | Professional & scientific | 2005 |
| JEM Property Management Limited | Real estate | 2009 |
| Jemis Properties Limited | Real estate | 2023 |
| Jemjay Medicare Limited | Health & social care | 2025 |
| Jemjo Healthcare Limited | Health & social care | 2009 |
| JEMMETT124 Ltd | Real estate | 2020 |
| JEN Hargreaves Holdings Ltd | Real estate | 2025 |
| JEN Lillian Coaching and Marketing Limited | Professional & scientific | 2022 |
| JEN Spence Production Limited | Information & communication | 2022 |
| Jenavalve Production Limited | Manufacturing | 2015 |
| Jenca Limited | Wholesale & retail | 2022 |
| Jenkins Marshall Limited | Real estate | 2017 |
| Jenna Plant Limited | Administrative & support | 2013 |
| Jennifer Bates Creative Limited | Information & communication | 2016 |
| Jennifer Ferrier Consulting Ltd | Professional & scientific | 2026 |
| Jennifer Pelter Hair Ltd | Other services | 2023 |
| Jennings Design Ltd | Administrative & support | 2000 |
| Jennings Group (Yorkshire) Ltd | Construction | 2020 |
| Jennings Holdings Ltd | Financial services | 2025 |
| Jennings Investments Ltd | Real estate | 2022 |
| Jennings of Pudsey Limited | Construction | 2018 |
| Jennings Property Management Limited | Real estate | 2022 |
| Jennions & Co Ltd | Professional & scientific | 2012 |
| Jenny Southwell Consulting Limited | Professional & scientific | 2021 |
| Jensen’S Delivery Ltd | Transport & logistics | 2025 |
| Jenson CD Limited | Financial services | 2020 |
| Jenson Funding Partners LLP | | 2012 |
| Jenson Knight Ltd | Administrative & support | 2015 |
| Jenson Partners LLP | | 2009 |
| Jenson Solutions Ltd | Professional & scientific | 2001 |
| JER Associates Management 2 Limited | Real estate | 2022 |
| JER IT Services Limited | Information & communication | 2019 |
| Jeremiah Investments Ltd | Real estate | 2025 |
| Jeremy Rider Properties Ltd | Hospitality | 2026 |
| Jerk Express Ltd | Hospitality | 2019 |
| Jescc Ltd | Transport & logistics | 2018 |
| Jesco Limited | Real estate | 2002 |
| JESMAN55 Prosperous Limited | Health & social care | 2019 |
| Jesmond Turkish Grill House Limited | Hospitality | 2018 |
| Jess - Noah's ARK Childcare Ltd | Professional & scientific | 2019 |
| Jess ANN Etele Ltd | Health & social care | 2024 |
| Jesscal Properties Limited | Real estate | 2025 |
| Jessica Hodkinson Ltd | Professional & scientific | 2019 |
| Jessica Jayne Properties Ltd | Real estate | 2021 |
| Jessica Nails Bar Limited | Other services | 2024 |
| Jessica's (Cookridge) Limited | Other services | 2007 |
| Jesss Ltd | Other services | 2026 |
| JET Filters Limited | Extraterritorial | 1932 |
| JET Multi Media Ltd | Information & communication | 2026 |
| JET2 Support Services (Spain) Limited | Administrative & support | 2016 |
| JET2 Transport Services Limited | Extraterritorial | 1988 |
| JET2 UK Limited | Extraterritorial | 2000 |
| JET2HOLIDAYS Limited | Administrative & support | 2002 |
| Jetglow Aircraft Engineering Limited | Manufacturing | 2008 |
| Jeto Holdings Limited | Financial services | 2018 |
| Jetready Limited | Administrative & support | 2024 |
| JETS4PETS Limited | Transport & logistics | 2004 |
| Jetsem Limited | Manufacturing | 2010 |
| Jetsoft Ltd | Information & communication | 2014 |
| Jett Property Management Ltd | Real estate | 2020 |
| Jetting and Drainage Pros Ltd | Construction | 2025 |
| Jetvexa Limited | Financial services | 2026 |
| Jeunessima Ltd | Professional & scientific | 2010 |
| Jewellery by Trudy Limited | Arts & recreation | 2017 |
| JEY Thurai Limited | Wholesale & retail | 2023 |
| JEZ Logan Academy Ltd | Education | 2026 |