| Jeyda Jade Ltd | Real estate | 2018 |
| JF Digital Solutions Ltd | Professional & scientific | 2024 |
| JF Francis Ltd | Professional & scientific | 2009 |
| JFF Collective Ltd | Financial services | 2020 |
| JFM Media Consulting Ltd | Professional & scientific | 2026 |
| JG London Ltd | Real estate | 2020 |
| JG TEX Decor Limited | Manufacturing | 2001 |
| JGE Investments Ltd | Real estate | 2025 |
| JGM Tutors Ltd | Education | 2017 |
| JH & CH Holdings Ltd | Financial services | 2026 |
| JH Greenfields Ltd | Real estate | 2020 |
| JH Transport & Removals Limited | Transport & logistics | 2025 |
| JHB Investment Holdings Limited | Real estate | 2025 |
| JHC Group Holdings Ltd | Financial services | 2017 |
| JHC Trustee Limited | Administrative & support | 2025 |
| JHS Global Ltd | Education | 2017 |
| Jia-Q Project Solutions Services Limited | Administrative & support | 2024 |
| Jigsaw Software Development Ltd | Information & communication | 2026 |
| Jill Music Limited | Information & communication | 1976 |
| Jill Music Productions Limited | Information & communication | 1966 |
| Jilsi Limited | Arts & recreation | 2019 |
| JJ Putting Limited | Wholesale & retail | 2022 |
| JJM Media Services Ltd | Information & communication | 2022 |
| JJM Records Limited | Information & communication | 2024 |
| Jjnmr Limited | Administrative & support | 2016 |
| Jjocm Ltd | Professional & scientific | 2022 |
| JJW Plumbing Ltd | Construction | 2019 |
| Jk's Creations Ltd | Manufacturing | 2013 |
| Jkjr Capital LLP | | 2021 |
| JKL Trading Ltd | Other services | 2024 |
| JKO Property Investments Limited | Real estate | 2015 |
| JLA (UK) Ltd | Professional & scientific | 2014 |
| JLA - Tax LLP | | 2014 |
| JLA 79 Holdings Ltd | Financial services | 2024 |
| JLA 79 Limited | Financial services | 2024 |
| JLA Mansfield Ltd | Professional & scientific | 2025 |
| JLA Professional Services Ltd | Administrative & support | 2025 |
| JLA Resources Ltd | Professional & scientific | 2026 |
| JLB Property Ltd | Construction | 2014 |
| JLE Building & Decoration Ltd | Construction | 2025 |
| JLM Management Solutions Limited | Professional & scientific | 2017 |
| JLS Finn Property Limited | Real estate | 2015 |
| JM Herts Solutions Ltd | Administrative & support | 2023 |
| JM Infrastructure Performance Services Ltd | Information & communication | 2012 |
| JM Online Retail Services Ltd | Professional & scientific | 2013 |
| JM Property Partnership Limited | Real estate | 2022 |
| JMC Studios Limited | Professional & scientific | 2020 |
| JMD Tiling Ltd | Construction | 2014 |
| JME Visions Limited | Extraterritorial | 2016 |
| JMH Property Holdings Limited | Real estate | 2016 |
| JMK Property Group Ltd | Real estate | 2019 |
| JMM Rentals Ltd | Real estate | 2023 |
| Jmshow Limited | Real estate | 2017 |
| JMW Creative Ltd | Information & communication | 2020 |
| JND Ltd | Construction | 2019 |
| JNM KGZ Limited | Transport & logistics | 2022 |
| Jnmc Estates Ltd | Real estate | 2025 |
| JNO Consulting Ltd | Information & communication | 2019 |
| JNP Solutions Limited | Information & communication | 2024 |
| JO Advisors UK Ltd | Financial services | 2022 |
| JO EM Ltd | Administrative & support | 2002 |
| JO Ireland Limited | Other services | 2020 |
| Joanne D Investments Ltd | Financial services | 2025 |
| Jobscyprus Ltd | Administrative & support | 2015 |
| JOE Raymond Estates Ltd | Households | 2011 |
| Joffe & Joffe Limited | Administrative & support | 2015 |
| John Charles Property Investments Ltd | Construction | 2004 |
| John F Bevan Limited | Arts & recreation | 2014 |
| John Groves Ticket Systems Ltd | Manufacturing | 2012 |
| John Hammick Ltd | Wholesale & retail | 2020 |
| John Kellys (Property Holding) Ltd | Administrative & support | 2022 |
| John Mcgrath Limited | Transport & logistics | 2009 |
| John Mckeown Clubs Limited | Hospitality | 2018 |
| John Properties Management Ltd | Construction | 2022 |
| John Rodriguez Yachts LLP | | 2017 |
| John the EYE Limited | Real estate | 2022 |
| John Trotter Trust | Health & social care | 2003 |
| John's Cycles Limited | Wholesale & retail | 2016 |
| John's Properties London Ltd | Real estate | 2021 |
| Johnny Construction Ltd | Construction | 2025 |
| Johnston Services Ltd | Administrative & support | 2022 |
| Johsan Investments Limited | Financial services | 2024 |
| Jolly Childminding Ltd | Health & social care | 2021 |
| Jolly FOX Ltd | Real estate | 2026 |
| Jonah Care Services Ltd | Health & social care | 2020 |
| Jonathan Thorpe Consultancy Limited | Financial services | 2020 |
| Jonduat Limited | Administrative & support | 2018 |
| Jones' Crumpets Ltd | Hospitality | 2017 |
| Jonoa Consultancy Ltd | Professional & scientific | 2025 |
| Jordana Properties Ltd | Real estate | 2021 |
| Joseda Advisory Ltd | Financial services | 2020 |
| Josh Halil Ltd | Information & communication | 2019 |
| Joshua Leigh & Co Audit Limited | Professional & scientific | 2022 |
| Joshua Leigh & Co Limited | Professional & scientific | 2013 |
| Joshua Leigh Financial Services Limited | Financial services | 2016 |
| Joshua Tree CX Ltd | Professional & scientific | 2016 |
| Joshua Tree IP Ltd | Administrative & support | 2024 |
| Josie Investments Ltd | Real estate | 2025 |
| Jostead UK Limited | Information & communication | 2023 |
| Jowett Electrical Limited | Construction | 2007 |