| J.L. Chen Ltd | Wholesale & retail | 2011 |
| J.N.J. Fabrications Limited | Professional & scientific | 1979 |
| J.O.E. Medical Services Limited | Health & social care | 2012 |
| J.P. Mass Limited | Financial services | 2026 |
| J.W.Buckley Limited | Manufacturing | 1964 |
| J.Walker Homes Limited | Construction | 2002 |
| J2SECOM Ltd | Wholesale & retail | 2026 |
| J41 Property Ltd | Real estate | 2024 |
| JA Control Solutions Ltd | Information & communication | 2023 |
| JA Hearing Ltd | Public administration | 2022 |
| JA Housing Group Ltd | Real estate | 2025 |
| JA Improvements Limited | Other services | 2024 |
| JA Mobile Tyres Ltd | Wholesale & retail | 2026 |
| JAA Floors & More Ltd | Construction | 2026 |
| Jaadan Limited | Wholesale & retail | 2025 |
| Jaas Services Ltd | Administrative & support | 2017 |
| Jaceconsultants Ltd | Professional & scientific | 2007 |
| Jack Radcliffe & Sons Limited | Transport & logistics | 1965 |
| Jack Taylor GAS Services Ltd | Construction | 2022 |
| Jackandwood Ltd | Administrative & support | 2021 |
| Jackie Bells Management Ltd | Households | 2022 |
| Jackson & Cooper Limited | Financial services | 2002 |
| Jackson and Foster Limited | Hospitality | 2025 |
| Jackson Brierley Harthan Limited | Professional & scientific | 2006 |
| Jackson Meadows Management Company Limited | Households | 2020 |
| Jackson's Roping Services Ltd | Manufacturing | 2019 |
| Jacksons MW Academy CIC | Education | 2024 |
| Jacksons MW Limited | Wholesale & retail | 2018 |
| Jacksons Renewables Ltd | Construction | 2012 |
| Jacob Dawson Engineering Ltd | Manufacturing | 2020 |
| Jacob Ford Performance Coaching Ltd | Arts & recreation | 2020 |
| Jacobs Properties Ltd | Other services | 2015 |
| Jade Farris Properties Ltd | Real estate | 2025 |
| Jade Garden Oldham Ltd | Hospitality | 2026 |
| Jade Industries Limited | Extraterritorial | 1997 |
| Jade Irving Limited | Professional & scientific | 2024 |
| Jade With Love Toys Limited | Wholesale & retail | 2025 |
| Jaderam Ltd | Real estate | 2017 |
| Jadore Bakery Ltd | Hospitality | 2025 |
| Jaffar Airlines Ltd | Real estate | 2025 |
| JAG Company Services Limited | Professional & scientific | 2004 |
| JAG Mgmt Ltd | Information & communication | 2024 |
| Jagers Limited | Real estate | 2007 |
| Jaguar Security Services Ltd | Administrative & support | 2021 |
| JAH Surveyors Ltd | Professional & scientific | 2026 |
| JAI Pyramid Ltd | Construction | 2025 |
| Jairo’S House Limited | Wholesale & retail | 2025 |
| Jak.K Properties (Rytn) Limited | Real estate | 2025 |
| Jake Scott Joinery Ltd | Construction | 2026 |
| Jakeman Brothers Limited | Real estate | 2008 |
| Jaketomsconstruction Ltd | Construction | 2023 |
| JAM Consulting (Oldham) Ltd | Professional & scientific | 2022 |
| Jamal Jewellers Limited | Wholesale & retail | 2025 |
| Jamba Ltd | Professional & scientific | 2012 |
| James and Peter Limited | Other services | 2020 |
| James Bayo Ltd | Administrative & support | 2023 |
| James Briggs (Holdings) Limited | Manufacturing | 2013 |
| James Briggs (Hygiene) Limited | Manufacturing | 2015 |
| James Briggs (IP) Limited | Manufacturing | 2013 |
| James Briggs Limited | Manufacturing | 2013 |
| James Dunkerley Steels Limited | Wholesale & retail | 1952 |
| James Edmund Wharton Limited | Real estate | 2012 |
| James H Vacations Ltd | Real estate | 2024 |
| James Howison Ltd | Construction | 2025 |
| James Maddox Photography Limited | Professional & scientific | 2008 |
| James Plumbing and Drainage Ltd | Construction | 2025 |
| James Scott (Accounting) LLP | | 2021 |
| James Todd T/A the Paintshop Ltd | Wholesale & retail | 2026 |
| James W Osborne Limited | Other services | 2023 |
| Jamie Parker Investments Ltd | Real estate | 2016 |
| Jamiil Limited | Wholesale & retail | 2023 |
| Jammu Kashmir TV CIC | Information & communication | 2025 |
| Jammu Rentals Limited | Real estate | 2026 |
| Jan's Store Ltd | Wholesale & retail | 2020 |
| Jane Cooksey Limited | Professional & scientific | 2002 |
| Jane Henthorn Ltd | Transport & logistics | 2021 |
| Jane James Holdings Ltd | Financial services | 2026 |
| Jane Seven Limited | Professional & scientific | 2025 |
| Jane Thomas Limited | Arts & recreation | 1985 |
| Janice Reed Design Limited | Administrative & support | 2016 |
| Janni Boutique Limited | Wholesale & retail | 2017 |
| Janni Boutique Online Limited | Wholesale & retail | 2021 |
| Janni Holdings Limited | Real estate | 2025 |
| Jansons Commercial Ltd | Real estate | 2024 |
| JAP Auto Group Ltd | Wholesale & retail | 2024 |
| Japanese Knotweed Plus Ltd | Administrative & support | 2015 |
| Jappa Jaguars Ltd | Transport & logistics | 2026 |
| Japs Auto Spares Oldham Ltd | Water & waste | 2015 |
| Jasmine Day Nursery Limited | Health & social care | 2026 |
| Jasmine Massage Ltd | Other services | 2013 |
| Jason Herd Events Ltd | Information & communication | 2021 |
| Jason Knight Limited | Construction | 2020 |
| Jason Lane Ltd | Construction | 2014 |
| Jason Rowley Ltd | Administrative & support | 2019 |
| JAT Construction Consultants Ltd | Professional & scientific | 2019 |
| JAT Property and Investments Ltd | Real estate | 2025 |
| Jatala Services Limited | Administrative & support | 2019 |
| Jatt Hygiene Ltd | Health & social care | 2025 |
| Jav's Golocal Limited | Wholesale & retail | 2024 |
| Jav's Property Ltd | Real estate | 2024 |