| Jiksaw Ltd | Professional & scientific | 2012 |
| Jilkorlogistics Limited | Transport & logistics | 2025 |
| Jimak Tactiq Integrated Services Ltd | Wholesale & retail | 2023 |
| Jimdustries Ltd | Wholesale & retail | 2019 |
| Jimmys Farm Ltd | Information & communication | 2006 |
| Jinc Beauty Ltd | Education | 2018 |
| JIT Food Limited | Wholesale & retail | 2024 |
| Jivox UK Limited | Professional & scientific | 2014 |
| JJ Cars Ipswich Ltd | Wholesale & retail | 2025 |
| JJ Domiciliary Limited | Households | 2023 |
| Jj's Private Hire Ltd | Transport & logistics | 2024 |
| Jj's Vapes Ltd | Wholesale & retail | 2024 |
| Jjlearmonth Limited | Arts & recreation | 2017 |
| Jj’S Pizzeria Ltd | Hospitality | 2025 |
| JK Electrical & Property Services Ltd | Construction | 2025 |
| JKD Ltd | Other services | 2012 |
| Jkld UK Limited | Professional & scientific | 1997 |
| Jknox Cycling Limited | Arts & recreation | 2019 |
| JKS Events Limited | Professional & scientific | 2010 |
| JL Sheppard Holdings Ltd | Construction | 2022 |
| Jleds Limited | Wholesale & retail | 2015 |
| JLL Group Limited | Professional & scientific | 2026 |
| JLR Roofing Ltd | Construction | 2020 |
| JLS Painters & Decorators Ltd | Construction | 2019 |
| Jlsnn Limited | Arts & recreation | 2022 |
| JM & Co. Properties Ltd | Real estate | 2021 |
| JM Environmental (East Anglia) Ltd | Construction | 2014 |
| JM Future Playscapes Ltd | Administrative & support | 2021 |
| JM Restart Limited | Information & communication | 2015 |
| JM Softworks Ltd | Information & communication | 2021 |
| Jm&M Electrical Limited | Construction | 2022 |
| JMA Sports Ltd | Professional & scientific | 2025 |
| JMC Darsham Ltd | Professional & scientific | 2017 |
| Jmcfita Limited | Transport & logistics | 2023 |
| Jmet Properties Ltd | Real estate | 2023 |
| JMG Limited | Hospitality | 1999 |
| JML Distributions Ltd | Wholesale & retail | 2025 |
| JML Plastering Limited | Construction | 2016 |
| JMP Building Contractors Ltd | Construction | 2020 |
| JMP Cleaning Ltd | Administrative & support | 2026 |
| JMP Land Limited | Agriculture & fishing | 1945 |
| JMP Plumbing and Heating Ltd | Construction | 2021 |
| Jmpzaby Limited | Wholesale & retail | 2023 |
| JMS Abacus Limited | Professional & scientific | 1997 |
| JMS Legacy Holdings Limited | Financial services | 2024 |
| JMS2 Ltd | Financial services | 2021 |
| Jmtem Limited | Real estate | 2024 |
| JN8 Ltd | Other services | 2015 |
| Jnissi Occupational Health Ltd | Health & social care | 2021 |
| JNR Transport Ltd | Transport & logistics | 2026 |
| Jntmedical Limited | Health & social care | 2016 |
| JO Jingles Limited | Education | 1995 |
| JO Powis Financial Planning Ltd | Financial services | 2021 |
| JO Probitts Arts Management Ltd | Arts & recreation | 2013 |
| Jo.D Haulage Ltd | Transport & logistics | 2026 |
| Joanna Rowsell Limited | Professional & scientific | 2018 |
| Jobi Medics Ltd | Health & social care | 2026 |
| Jocipapa Ltd | Transport & logistics | 2026 |
| JOD Athletics Limited | Arts & recreation | 2024 |
| JOE Befriending Healthcare Limited | Transport & logistics | 2021 |
| JOE Catchpole Ltd | Professional & scientific | 2014 |
| JOE Healthcare Ltd | Administrative & support | 2017 |
| Joev Properties Ltd | Real estate | 2025 |
| Jogas Go Ltd | Transport & logistics | 2025 |
| Jogi Clothing Ltd | Wholesale & retail | 2026 |
| Johal Surgical Limited | Health & social care | 2019 |
| John Alan Property Solutions Limited | Construction | 2015 |
| John Antony Chapman Limited | Health & social care | 2025 |
| John Barry Finance Limited | Wholesale & retail | 1963 |
| John Denny Associates Limited | Professional & scientific | 2008 |
| John Denton Limited | Information & communication | 2020 |
| John Ferguson Studio CIC | Professional & scientific | 2025 |
| John Howard Education Ltd | Professional & scientific | 2022 |
| John Howard Property Consultants Limited | Real estate | 1999 |
| John Keeble (Bramford) Limited. | Wholesale & retail | 1985 |
| John Keeble Limited | Wholesale & retail | 2020 |
| John Marcena Neufang Ltd | Health & social care | 2015 |
| John Parker Fixings Ltd | Wholesale & retail | 2022 |
| John R. Morris & SON (Property) Limited | Construction | 1991 |
| John Spear Traditional Crafts Limited | Manufacturing | 2018 |
| John White & Red Transport Ltd | Transport & logistics | 2016 |
| John&Sons Haulage Limited | Transport & logistics | 2015 |
| Johns Slater and Haward Limited | Professional & scientific | 2004 |
| Johnson Snell & Woods Limited | Construction | 2000 |
| Joint Venture Partnership Limited | Real estate | 2023 |
| Jojo's Swim School Limited | Other services | 2023 |
| Jolantido Ltd | Professional & scientific | 2025 |
| Jolb Ltd | Real estate | 2016 |
| Jolly Assets Holdings Limited | Financial services | 2023 |
| Jolly Assets Limited | Financial services | 2023 |
| JOM Associates Limited | Professional & scientific | 2017 |
| Jomanda Properties Ltd | Construction | 2010 |
| Jomeada Properties Limited | Real estate | 2020 |
| Jonathan Brownlee Ltd | Other services | 2010 |
| Jonathan Mark Atkinson Ltd | Extraterritorial | 2022 |
| Jonathan Trans Limited | Transport & logistics | 2024 |
| Jones Carpentry Construction Ltd | Manufacturing | 2021 |
| Jonma Group Ltd | Financial services | 2025 |
| Jonma Properties Ltd | Real estate | 2022 |
| Jonnie Peacock Limited | Arts & recreation | 2013 |