| J G Plumbing Heating Ltd | Construction | 2025 |
| J Gerrard Ltd | Professional & scientific | 2012 |
| J Holmes Investments Ltd | Real estate | 2023 |
| J Huggins and SON Limited | Wholesale & retail | 1977 |
| J J K Project Services Limited | Professional & scientific | 2010 |
| J K E Limited | Manufacturing | 2003 |
| J K Specialist Interiors Ltd. | Construction | 2006 |
| J M Milk Ltd | Wholesale & retail | 2023 |
| J P Services (Chesterfield) Limited | Professional & scientific | 2010 |
| J R Hoult & Grandson Ltd | Other services | 2011 |
| J Rogers Haulage Limited | Transport & logistics | 2016 |
| J S Brown Property Limited | Real estate | 2023 |
| J S Groundworks Ltd | Construction | 2020 |
| J S Thorpe Ltd | Administrative & support | 2024 |
| J Smith & SON Developments Ltd | Construction | 2025 |
| J Smith and Sons Properties Ltd | Real estate | 2026 |
| J T Crane Construction Limited | Construction | 2010 |
| J W Commercial Repairs Ltd | Wholesale & retail | 2021 |
| J Z Khan Ltd | Health & social care | 2025 |
| J&Jp Properties Ltd | Real estate | 2026 |
| J&P Simpson Limited | Construction | 2016 |
| J&Y Webber Services Limited | Health & social care | 2011 |
| J,T and K, Water Industry, Engineering Ltd | Professional & scientific | 2019 |
| J-Kays Cleaning Services Ltd | Other services | 2019 |
| J. a. B. Short, Limited | Construction | 1946 |
| J. Smith Holdings Limited | Real estate | 1999 |
| J. Vernon Limited | Health & social care | 2022 |
| J.A. Wills & Trusts Ltd | Professional & scientific | 2018 |
| J.A.S. Sports Distribution Limited | Arts & recreation | 2023 |
| J.Bayne Installations Limited | Construction | 1962 |
| J.H.B Class 1 Ltd | Transport & logistics | 2012 |
| J.H.Electrics Ltd | Construction | 2025 |
| J.Hole & Sons Limited | Agriculture & fishing | 1957 |
| J.Pugh-Lewis Limited | Construction | 1966 |
| J.S. Properties & Sons Ltd | Real estate | 2023 |
| J.Sea.P Limited | Transport & logistics | 2019 |
| J.W. Richards & Sons Ltd | Wholesale & retail | 2018 |
| J.Wright Sales Ltd | Extraterritorial | 2023 |
| J2 Creative Ltd | Information & communication | 2023 |
| J4A Limited | Professional & scientific | 2020 |
| JA Hopkinson & SON Ltd | Agriculture & fishing | 2022 |
| Jaay's Recovery Ltd | Transport & logistics | 2025 |
| Jabes Ltd | Transport & logistics | 2016 |
| Jaccon Ltd | Construction | 2010 |
| Jack & Ellis Ltd | Other services | 2019 |
| Jack of ALL Fades (Chesterfield) Ltd | Other services | 2025 |
| Jackpipe (UK) Limited | Administrative & support | 2009 |
| Jackson Consultants Limited | Professional & scientific | 2021 |
| Jackson Factory Services Limited | Professional & scientific | 2025 |
| Jacksons Fruit and VEG Ltd | Wholesale & retail | 2024 |
| Jacobs Tree & Landscapes Ltd | Administrative & support | 2024 |
| Jade Palace Food Ltd | Hospitality | 2024 |
| Jades Express Limited | Hospitality | 2024 |
| Jadestone Property Developments Limited | Real estate | 2019 |
| JAG Industries Limited | Manufacturing | 2013 |
| JAG Manufacturing Limited | Manufacturing | 2013 |
| Jahp Limited | Professional & scientific | 2019 |
| Jaishiv Bowers Limited | Other services | 2024 |
| JAK Johnson Transport Services Ltd | Transport & logistics | 2025 |
| Jakalimo Ltd | Financial services | 2024 |
| JAM Domestic Properties Ltd | Real estate | 2023 |
| JAM IT Ltd | Real estate | 2025 |
| Jamac Construction Limited | Construction | 2017 |
| Jamadan Ltd | Manufacturing | 2012 |
| James & Graven Limited | Professional & scientific | 1999 |
| James and Graven Holdings Limited | Professional & scientific | 2015 |
| James and Graven Holdings Soham Limited | Professional & scientific | 2015 |
| James and John Property Limited | Real estate | 2021 |
| James Bevan & Sons Garden & Household Services Ltd | Administrative & support | 2026 |
| James Construction and Developments Limited | Real estate | 2014 |
| James Convenience Retail Limited | Wholesale & retail | 2015 |
| James Farms and Consultancy Limited | Agriculture & fishing | 2012 |
| James Financial and Investments Limited | Financial services | 2014 |
| James Graven and Sons Limited | Real estate | 1959 |
| James Gregory Holdings Limited | Financial services | 2024 |
| James Gunter Rope Access Limited | Construction | 2018 |
| James Residential Properties Limited | Real estate | 2022 |
| James Retail Limited | Wholesale & retail | 2016 |
| James Retail Soham Limited | Real estate | 2015 |
| James Toseland Music Limited | Information & communication | 2012 |
| Jamie Lilley Consultancy Limited | Financial services | 2018 |
| Jamiella Ltd | Professional & scientific | 2026 |
| JAN Associates IT Limited | Information & communication | 2019 |
| Jane & Steve Gill Limited | Administrative & support | 2000 |
| Jane Preston Limited | Health & social care | 2018 |
| Janis Property Services Ltd | Real estate | 2016 |
| Jantex UK Ltd. | Professional & scientific | 1998 |
| Japanese Auto Solution Limited | Wholesale & retail | 2023 |
| Jardine OH Consultancy Ltd | Health & social care | 2015 |
| Jarman Resources Ltd | Professional & scientific | 2008 |
| Jarvis and SON Holdings Ltd | Hospitality | 2023 |
| Jasmin Jade Health and Beauty Ltd | Other services | 2022 |
| Jason Ellis Wealth Management Limited | Financial services | 2015 |
| Jason Rawson Carpets Limited | Wholesale & retail | 2011 |
| Jason Wood Delivery Services Ltd | Transport & logistics | 2024 |
| Jasond Ltd | Other services | 2019 |
| Jasu E CIG Ltd | Wholesale & retail | 2025 |
| Jaxon Travel Limited | Transport & logistics | 2010 |
| JAY Logan Home Developments Ltd | Construction | 2025 |
| JAY M Ltd | Administrative & support | 2025 |