| Jameson Financial Services Limited | Financial services | 2019 |
| Jameson's Gifts & Antiques Ltd | Wholesale & retail | 2020 |
| Jamesons Tearoom and Kitchens Ltd | Hospitality | 2020 |
| Jameya Ltd | Real estate | 2026 |
| Jamha Properties Ltd | Real estate | 2019 |
| Jamia DAR UL Uloom Qadiria Jillania Multicultural Centre Ltd | Hospitality | 2020 |
| Jamie Burns Transformations Ltd | Education | 2023 |
| Jamie Holgate Ltd | Information & communication | 2025 |
| Jamie Martin Electrical Ltd | Construction | 2016 |
| Jamie Sutton Accountancy Ltd | Professional & scientific | 2025 |
| Jammu Joiners Ltd | Manufacturing | 2025 |
| Jammy Lodger Ltd | Real estate | 2009 |
| Jamoom Property Limited | Real estate | 2025 |
| JAN1083 Limited | Financial services | 2024 |
| Jana Tractor Parts UK Ltd | Wholesale & retail | 2026 |
| Janami Properties Ltd | Real estate | 2017 |
| Janbro International Ltd | Manufacturing | 2026 |
| Jande&Co Limited | Wholesale & retail | 2025 |
| Jane Clift Associates Ltd | Information & communication | 2013 |
| Jane Fardon Consulting Limited | Other services | 2007 |
| Jane House Limited | Health & social care | 2012 |
| Jane Locke Associates Ltd | Information & communication | 2002 |
| Janelles Closet Limited | Wholesale & retail | 2026 |
| Janels Ltd | Hospitality | 2025 |
| Janet Hutchinson Ltd | Wholesale & retail | 2019 |
| Jangso Restaurant Limited | Hospitality | 2022 |
| Janicker Limited | Arts & recreation | 2018 |
| Jankowski Properties Ltd | Real estate | 2025 |
| JAP Campers Limited | Wholesale & retail | 2026 |
| JAP Motors (Sheffield) Limited | Wholesale & retail | 2017 |
| JAP TEC Limited | Wholesale & retail | 2022 |
| Japanese Import Solutions Ltd | Wholesale & retail | 2026 |
| Japs Spares Ltd | Wholesale & retail | 2016 |
| JAR Technology Holdings Limited | Information & communication | 2017 |
| JARBO3 Ltd | Wholesale & retail | 2020 |
| Jared Wood Ltd | Administrative & support | 2013 |
| Jarmula Property Ltd | Real estate | 2024 |
| Jarvis City Living Limited | Real estate | 2023 |
| Jarvis Property Lettings Limited | Real estate | 2014 |
| Jarvis Student Properties Limited | Real estate | 2003 |
| JAS Holdings Limited | Administrative & support | 2016 |
| JAS Mortgages Limited | Financial services | 2020 |
| JAS Social Care Consultancy Limited | Health & social care | 2011 |
| Jasbirr Grover Ltd | Information & communication | 2024 |
| Jasbri Trading Limited | Administrative & support | 2019 |
| Jasen Group Limited | Extraterritorial | 2024 |
| Jask Limited | Hospitality | 1999 |
| Jasobi Homes Ltd | Real estate | 2022 |
| Jason Beaumont Power Solutions Ltd | Manufacturing | 2016 |
| Jason Scholey Law Firm Advisory Ltd | Professional & scientific | 2024 |
| Jaunty Healthcare Limited | Wholesale & retail | 2021 |
| Javan Hayles Limited | Arts & recreation | 2015 |
| Javed Taxi Services Ltd | Transport & logistics | 2026 |
| Javel Reach Ltd | Professional & scientific | 2024 |
| Javelin Payments UK Limited | Information & communication | 2021 |
| Javisionsuk Ltd | Professional & scientific | 2025 |
| Javlin Property Ltd. | Real estate | 2016 |
| Jawad Group Ltd | Administrative & support | 2025 |
| Jawbone Bikes Ltd | Manufacturing | 2025 |
| JAX Nation Productions Ltd | Information & communication | 2025 |
| JAY CUT Barbers Ltd | Other services | 2025 |
| JAY Hair Design Ltd | Other services | 2019 |
| Jay's Healthcare Ltd | Health & social care | 2014 |
| Jay's Refractory Specialists Limited | Wholesale & retail | 1984 |
| Jayamony Ltd | Information & communication | 2010 |
| Jaycee Developments Ltd | Construction | 2019 |
| Jaychlo Limited | Information & communication | 2025 |
| Jaye's Fusion Ltd | Hospitality | 2024 |
| Jayjay Tools Ltd | Wholesale & retail | 2020 |
| Jayland Edrick Ltd | Real estate | 2024 |
| Jayleia Consultancy Ltd | Health & social care | 2015 |
| Jaymar Solutions Ltd | Construction | 2022 |
| Jays Electrical & Maintenance Ltd | Construction | 2026 |
| Jays Leisure Ltd | Hospitality | 2025 |
| JAZ Services South Yorkshire Limited | Real estate | 2012 |
| Jazz Marcus Construction Ltd | Construction | 2019 |
| Jazzie K Limited | Transport & logistics | 2019 |
| Jazzy Trading Limited | Water & waste | 2015 |
| JB Automotive Ltd | Wholesale & retail | 2019 |
| JB Autos (Penistone) Limited | Wholesale & retail | 2022 |
| JB Business Limited | Professional & scientific | 2009 |
| JB Cleaning and Maintenance Ltd | Construction | 2025 |
| JB F&B Ltd | Other services | 2011 |
| JB Grab Hire Ltd | Transport & logistics | 2015 |
| JB Investment Management Limited | Real estate | 2023 |
| JB Project & Design Services Limited | Professional & scientific | 2016 |
| JB Properties and Lettings Ltd | Real estate | 2023 |
| JB Property Development & Management Ltd | Real estate | 2023 |
| JB Renovations & Maintenance Limited | Construction | 2025 |
| JB SAS Ltd | Other services | 2023 |
| JB Social Housing Investments Ltd | Real estate | 2023 |
| JB Trade and Transport Ltd | Water & waste | 2022 |
| JB Vine Limited | Professional & scientific | 2025 |
| Jb&E Contracting Ltd | Construction | 2016 |
| JBA Flooring Limited | Construction | 2024 |
| Jbaker Taverns Ltd | Hospitality | 2025 |
| JBC Business Consulting Limited | Professional & scientific | 2011 |
| JBC Euro Ltd | Other services | 2016 |
| JBD Accountants Ltd | Administrative & support | 2019 |
| JBD Accountants NO2 Limited | Professional & scientific | 2026 |