| JPS Servics Limited | Real estate | 2025 |
| JQ Electrical Ltd | Construction | 2023 |
| JR Bestevents Limited | Hospitality | 2022 |
| JR Decor (UK) Limited | Construction | 2019 |
| JR Fabric Ltd | Wholesale & retail | 2024 |
| JR Motorsports Limited | Wholesale & retail | 2007 |
| Jr&Lt Clothing Ltd | Wholesale & retail | 2026 |
| Jr&Lt Ltd | Manufacturing | 2023 |
| JR40PLASTERING Limited | Construction | 2019 |
| JRA Property Solutions Ltd | Administrative & support | 2026 |
| JRB Consulting Solutions Ltd | Professional & scientific | 2019 |
| JRB Removals Limited | Water & waste | 2025 |
| JRC Business Consulting Ltd | Professional & scientific | 2020 |
| JRC Restoration Ltd | Administrative & support | 2020 |
| JRF Group Ltd | Wholesale & retail | 2022 |
| JRI Services Ltd | Construction | 2017 |
| Jright Group Ltd | Professional & scientific | 2022 |
| JRJ Medical Recruitment Ltd | Administrative & support | 2023 |
| JRJ Plumbing & Heating Limited | Construction | 2019 |
| JRM Advanced Engineering Limited | Manufacturing | 2014 |
| JRM Group Limited | Financial services | 2016 |
| JRP Electrical Ltd | Construction | 2023 |
| JRP Properties Ltd | Real estate | 2023 |
| JRS Engineering UN Limited | Professional & scientific | 2023 |
| JRW Motor Vehicles Group Ltd | Transport & logistics | 2015 |
| JRX Consulting Limited | Professional & scientific | 2025 |
| JRY Construction Limited | Construction | 2020 |
| JRZ2 Ltd | Transport & logistics | 2011 |
| JS Automotive Consultancy Ltd | Professional & scientific | 2025 |
| JS Driver Northampton Ltd | Transport & logistics | 2022 |
| JS Getaways Ltd | Hospitality | 2025 |
| JS Motors Limited | Wholesale & retail | 2026 |
| JS Property Maintenance Roofing and Building Contractors Ltd | Construction | 2018 |
| JS Sandhu Limited | Professional & scientific | 2007 |
| JS2 Promotions Limited | Arts & recreation | 2018 |
| JSA Security Limited | Administrative & support | 2023 |
| JSB Car Repairs Ltd | Wholesale & retail | 2021 |
| JSB Cleaning Services Ltd | Administrative & support | 2025 |
| JSB Print Solutions Ltd | Administrative & support | 2010 |
| JSC RTM Company Limited | Households | 2018 |
| JSC Transport Ltd | Transport & logistics | 2025 |
| JSD Ltd | Construction | 2021 |
| JSF Brickwork Services Limited | Construction | 2018 |
| JSF Maintenance Ltd | Administrative & support | 2015 |
| JSG Consulting Ltd | Professional & scientific | 2006 |
| JSJ Construction (Midlands) Limited | Construction | 2014 |
| Jsjn Limited | Wholesale & retail | 2016 |
| Jsmb Limited | Professional & scientific | 2003 |
| Jsmg Limited | Hospitality | 2012 |
| JSR Consulting Services Limited | Professional & scientific | 2018 |
| Jsrai Limited | Transport & logistics | 2026 |
| JST Leisure Ltd | Construction | 2018 |
| Jsth Limited | Water & waste | 2014 |
| JSZ Northampton Ltd | Construction | 2023 |
| JT Cegielski Ltd | Wholesale & retail | 2012 |
| JT Landscape Services Limited | Administrative & support | 2019 |
| JTP Tiling Ltd | Construction | 2021 |
| Jtrb Communications Limited | Professional & scientific | 2014 |
| JTS Kitchens Limited | Construction | 2020 |
| JTS Security Systems Limited | Administrative & support | 2012 |
| Juan Juan Oriental Center Ltd | Health & social care | 2018 |
| JUB Trans Ltd | Transport & logistics | 2026 |
| Jubeerich UK Ltd | Education | 2023 |
| Jubilee Court (Chilterns) Management Company Limited | Households | 2002 |
| Judeandkaram Ltd | Health & social care | 2018 |
| Judelin Private Limited | Hospitality | 2025 |
| Judextservices &Practice Limited | Other services | 2023 |
| Jugaru Ltd | Construction | 2016 |
| Juice From the RAW UK Ltd | Extraterritorial | 2015 |
| Julantho Ltd | Real estate | 2025 |
| Julia Marie Collings Limited | Professional & scientific | 2025 |
| Julie Healthcare Limited | Health & social care | 2009 |
| Juliet AMA Limited | Health & social care | 2022 |
| Juliet Karen Sharpe Limited | Extraterritorial | 2021 |
| Julieta M Cleaning Ltd | Administrative & support | 2025 |
| Julieta Stoica Ltd | Transport & logistics | 2022 |
| Julio Ruiz Taberna Ltd | Transport & logistics | 2025 |
| Julka Ltd | Transport & logistics | 2025 |
| Julka Services Ltd | Transport & logistics | 2022 |
| Jumacel Limited | Information & communication | 2025 |
| Jumbo FPA Ltd | Transport & logistics | 2015 |
| Jumise BIM Services Ltd | Professional & scientific | 2025 |
| Jump Dogs UK Ltd | Arts & recreation | 2019 |
| Jump Media Group Limited | Administrative & support | 2015 |
| Jump Think Limited | Professional & scientific | 2021 |
| Jumuna Kebab and Balti House Ltd | Hospitality | 2019 |
| Jumy Ltd | Wholesale & retail | 2024 |
| Junction 18 Street Foods Limited | Hospitality | 2012 |
| Junction Fifteen Limited | Professional & scientific | 2013 |
| Junction Nine Design Consultants Limited | Administrative & support | 1999 |
| JUNCTION15 Scaffolding Services Ltd | Construction | 2025 |
| June House Limited | Hospitality | 2024 |
| Jungle DE Beton Ltd | Manufacturing | 2026 |
| Jungle Red (Abington Park) Ltd | Other services | 2026 |
| Jungle Red Hair & Beauty Limited | Other services | 2009 |
| Juniper Living Limited | Construction | 2017 |
| Juniper Marketing Ltd | Administrative & support | 2012 |
| Junk Army Ltd | Water & waste | 2025 |
| Junk Monkey Clearance Ltd | Water & waste | 2024 |
| Juno Design Studio Ltd | Professional & scientific | 2026 |