| Jamm Co 2019 Ltd | Financial services | 2019 |
| Jamo Holdings Limited | Wholesale & retail | 2020 |
| Jamwest Limited | Wholesale & retail | 2023 |
| Jamworks Dale Street Limited | Professional & scientific | 2013 |
| JAN Housing Limited | Real estate | 2025 |
| JAN PIZZA197 Ltd | Hospitality | 2025 |
| JAN Truck Ltd | Transport & logistics | 2021 |
| JAN Walsh & Co Ltd | Other services | 2014 |
| Janat First Ltd | Wholesale & retail | 2012 |
| Jane Clark Limited | Administrative & support | 2013 |
| Jane Cornforth Ltd | Manufacturing | 2024 |
| Jane Leah Consults Ltd | Professional & scientific | 2013 |
| Jane Parry Ltd | Other services | 2011 |
| Jane Sampson Limited | Professional & scientific | 2009 |
| Janet and Brian Waters Trading Limited | Professional & scientific | 2016 |
| Janet GOW Photography Ltd | Professional & scientific | 2006 |
| Janet Millwood Trading Limited | Professional & scientific | 2016 |
| Janet Woods Consulting Limited | Professional & scientific | 2019 |
| Jangenix Limited | Wholesale & retail | 2022 |
| Jangi Hospitality Ltd | Hospitality | 2024 |
| Jani Zotaj Ltd | Transport & logistics | 2024 |
| Janice Evans Clinical Services Ltd | Health & social care | 2024 |
| Janice Tullock Associates Limited | Arts & recreation | 2015 |
| Janie Rees Ltd | Wholesale & retail | 2016 |
| JANMARCONSULTING2 Limited | Professional & scientific | 2016 |
| Janor Properties Limited | Real estate | 2020 |
| Jantrans Limited | Transport & logistics | 2001 |
| Jants Chaptersz - Steve Black Trading Limited | Professional & scientific | 2023 |
| Janu NW Ltd | Wholesale & retail | 2026 |
| Janu Super Store Ltd | Wholesale & retail | 2024 |
| Janusz Rubaj Transport Ltd. | Transport & logistics | 2016 |
| Janwise Limited | | 1981 |
| JAQ Safety Ltd | Professional & scientific | 2022 |
| JAR Construction (North West) Limited | | 2011 |
| JAR Management Limited | Construction | 2016 |
| Jarade Services Ltd | Professional & scientific | 2012 |
| Jarco Investments Limited | Real estate | 2018 |
| Jardine's Joinery Wirral Ltd | Manufacturing | 1977 |
| Jare Media Advertising Group Ltd | Professional & scientific | 2022 |
| JARK-1 Limited | Professional & scientific | 2017 |
| Jaroslav Joinery Ltd | Construction | 2025 |
| Jarrad and Nicola Rose Ltd | Health & social care | 2023 |
| Jart D Ltd | Real estate | 2025 |
| Jarvis Aquatics Limited | Administrative & support | 2019 |
| Jarvis Financial Ltd | Financial services | 2013 |
| JAS Housing Solutions Limited | Real estate | 2012 |
| JAS Steel Ltd | Other services | 2023 |
| Jas&Jas Ltd | Wholesale & retail | 2023 |
| Jase in Tech Ltd | Information & communication | 2024 |
| Jasell Limited | Professional & scientific | 2009 |
| Jashim Ltd | Health & social care | 2014 |
| Jashora Technologies Ltd | Manufacturing | 2026 |
| Jasmine Greene Ltd | Other services | 2026 |
| Jasmine Hazel Grove Ltd | Construction | 2021 |
| Jasmine’S Cleaning Services Ltd | Manufacturing | 2026 |
| Jasnas Limited | Wholesale & retail | 2021 |
| Jason and Jenny Limited | Administrative & support | 2018 |
| Jason's Kitchen Limited | Hospitality | 2025 |
| Jason’S Convenience & Liquors Limited | Wholesale & retail | 2025 |
| Jasp Ltd | Hospitality | 2021 |
| Jaspers Healthcare Limited | Administrative & support | 2016 |
| Jassim Trading Ltd | Wholesale & retail | 2024 |
| Jast Consulting Limited | Professional & scientific | 2024 |
| Jasthu Ltd | Wholesale & retail | 2018 |
| JAT Consultancy Limited | Professional & scientific | 2007 |
| Jatraa Events UK Ltd | Hospitality | 2025 |
| Java Bonito Limited | Manufacturing | 2024 |
| Java News Wine Ltd | Wholesale & retail | 2019 |
| Java to Go Ltd | Hospitality | 2003 |
| Javid Property Management Limited | Construction | 2020 |
| JAW Corporations Ltd | Real estate | 2024 |
| JAW Estates Ltd | Construction | 2007 |
| Jawad 786 Ltd | Wholesale & retail | 2025 |
| JAX Engineering Holdings Limited | Financial services | 2018 |
| Jaxon’S Micropub Ltd | Hospitality | 2019 |
| Jaxtec Ltd | Wholesale & retail | 2025 |
| Jaxvi Care Solutions Limited | Administrative & support | 2023 |
| JAY Development Property Company (Liverpool) Ltd. | Construction | 1995 |
| JAY JT Taylor Services Limited | Health & social care | 2025 |
| JAY Properties Investment Ltd | Real estate | 2019 |
| JAY Real Estate Ltd | Real estate | 2024 |
| JAY Tyres Ltd | Wholesale & retail | 2021 |
| JAY Tyres NW Ltd | Wholesale & retail | 2025 |
| Jay-Vez Limited | Information & communication | 2023 |
| Jayb Powder Coating Limited | Construction | 2018 |
| Jaycure Ltd | Wholesale & retail | 2022 |
| Jayde Spa Manchester Limited | Other services | 2025 |
| Jaykrys Limited | Hospitality | 2023 |
| Jaymac Contracting Services Limited | Financial services | 2013 |
| Jaynestreet Limited | Real estate | 2010 |
| Jays Booze Ltd | Wholesale & retail | 2026 |
| Jays Cleaning Products Ltd | Wholesale & retail | 2019 |
| Jays Electrical NW Limited | Construction | 2022 |
| Jays Express Ltd | Wholesale & retail | 2022 |
| Jays Wine Limited | Wholesale & retail | 2023 |
| Jayswindows Limited | Manufacturing | 2025 |
| Jazzainthecommunity Ltd | Education | 2020 |
| JB (Wallasey) Limited | Health & social care | 2026 |
| JB Best 4U Ltd | Administrative & support | 2024 |
| JB Chicken Ltd | Hospitality | 2025 |