| J.Alex Swift Holdings Limited | Financial services | 2022 |
| J.B Capital Holdings Ltd | Financial services | 2015 |
| J.B. Landscapes Limited | Administrative & support | 2008 |
| J.C. Brown & Co. Plumbing & Heating Limited | Construction | 1978 |
| J.D.Mccann Properties Ltd | Real estate | 2024 |
| J.D.S.P Commercial Limited | Real estate | 2024 |
| J.D.S.P Holding Ltd | Real estate | 2023 |
| J.D.S.P. Dental Limited | Health & social care | 2007 |
| J.Daviespropertydevelopment Ltd | Real estate | 2024 |
| J.E. Whittlesey & Co. | Construction | 1960 |
| J.E.M. Amusements Limited | Arts & recreation | 2011 |
| J.E.M. Leisure Limited | Arts & recreation | 1986 |
| J.G.S.Dawson Limited | Wholesale & retail | 1959 |
| J.H. Wilson (Arnold) Limited | Real estate | 1970 |
| J.I.T. Holdings Limited | Financial services | 2003 |
| J.I.T. Logistics Limited | Transport & logistics | 1996 |
| J.J. & M.D. Knight Limited | Manufacturing | 1991 |
| J.L. Management Consultants Limited | Professional & scientific | 2007 |
| J.M Engineering&Surveying Ltd | Professional & scientific | 2018 |
| J.M.& I Services Ltd | Transport & logistics | 2019 |
| J.M.B Property Holdings Ltd | Real estate | 2019 |
| J.Moss Joinery and Building Services Ltd | Construction | 2025 |
| J.N. Derbyshire Trust | Health & social care | 1944 |
| J.N. Key Holdings Ltd | Administrative & support | 2018 |
| J.N.Key Logistics Ltd | Transport & logistics | 2018 |
| J.N.Rowen Limited | Construction | 1949 |
| J.O.Cole Holdings Ltd | Financial services | 2026 |
| J.P Osmens Limited | Wholesale & retail | 2024 |
| J.P. Hargreaves Group Limited | Financial services | 2026 |
| J.P.C. Properties (2025) Limited | Real estate | 2025 |
| J.P.C.Builders Limited | Construction | 2014 |
| J.P.Hargreaves Property Consulting Limited | Real estate | 2026 |
| J.R. Islip & Sons Limited | Manufacturing | 2023 |
| J.S. Sagoo Limited | Other services | 2010 |
| J.S.Phull Limited | Construction | 2019 |
| J.T's Domestic Maintenance Limited | Construction | 2018 |
| J.T. Hodson Electrical Contractors Limited | Construction | 2008 |
| J.T.Beedham & Sons Limited | Manufacturing | 1957 |
| J.Tarbuck Electrical Services Ltd | Construction | 2023 |
| J.V. Logistics (Nottingham) Ltd | Transport & logistics | 2023 |
| J.W.Engineering Limited | Manufacturing | 1970 |
| J2 Creations Ltd | Professional & scientific | 2020 |
| J2 M&E Services Ltd | Construction | 2025 |
| J26 Limited | Real estate | 2025 |
| J26 Vans&Trucks Ltd | Wholesale & retail | 2020 |
| J28 Sales & Lettings Limited | Real estate | 2025 |
| J3-MECHANICAL Limited | Construction | 2026 |
| J41D Ltd | Information & communication | 2020 |
| J4Y-PROMOTIONS Ltd | Wholesale & retail | 2024 |
| JA & M Squared Consulting Ltd | Real estate | 2020 |
| JA Cabs Limited | Transport & logistics | 2021 |
| JA Otim Limited | Health & social care | 2018 |
| JA Property Lettings Ltd | Real estate | 2026 |
| JA Siddall Ltd | Real estate | 2011 |
| JA Waterproofing Specialists Ltd | Construction | 2023 |
| JA14 RAS Cosmetics Limited | Other services | 2023 |
| JA14 RAS Property Limited | Real estate | 2023 |
| Jaaljo Limited | Real estate | 2013 |
| Jaan Rajput Ltd | Administrative & support | 2026 |
| Jaani Limited | Wholesale & retail | 2025 |
| Jaap Travels and Services Ltd | Transport & logistics | 2023 |
| Jaasks Holdings Limited | Financial services | 2021 |
| JAB Joinery (Nottm) Ltd | Construction | 2018 |
| Jabar Structures Limited | Construction | 2024 |
| Jabra Holdings Limited | Real estate | 2023 |
| JAC Writing Services Limited | Administrative & support | 2015 |
| Jacamar Health and Care Services Ltd | Health & social care | 2026 |
| Jacanda Ltd | Real estate | 2020 |
| Jacanid Ltd | Financial services | 2024 |
| Jacd Investments Ltd | Households | 2024 |
| Jacdaw Engineering Ltd | Mining & quarrying | 2011 |
| Jack Chadbourn Ltd | Information & communication | 2024 |
| Jack Hamson Cleaning Ltd | Administrative & support | 2020 |
| Jack Jones Plant Hire Limited | Administrative & support | 2021 |
| Jack Logistics Ltd | Transport & logistics | 2021 |
| Jack Mccormick Ltd | Professional & scientific | 2024 |
| Jack Murdoch Ltd | Wholesale & retail | 2025 |
| Jack Wainwright Construction Ltd | Transport & logistics | 2015 |
| Jackal Technologies Ltd | Transport & logistics | 2026 |
| Jackpot Cash & Carry Ltd | Wholesale & retail | 2022 |
| Jacks & Buckley Ltd | Other services | 2018 |
| Jacks Home Discount Ltd | Wholesale & retail | 2023 |
| Jacksdale Butchers Ltd | Wholesale & retail | 2026 |
| Jacksdale Chippy Ltd | Hospitality | 2022 |
| Jacksdale Social Club Limited | Hospitality | 2012 |
| Jackson & Keay Limited | Manufacturing | 1991 |
| Jackson & Lakin(Freckingham Street)Limited | Real estate | 1959 |
| Jackson & Lakin,Limited | Real estate | 1952 |
| Jackson 1NE Ltd | Professional & scientific | 2024 |
| Jackson Crane Architecture Ltd | Professional & scientific | 2017 |
| Jackson Design & Build Ltd | Construction | 2025 |
| Jackson Homes (Scopwick) Limited | Construction | 1973 |
| Jackson Joiners & Builders Limited | Construction | 2006 |
| Jackson's Cooling Limited | Construction | 2021 |
| Jacksonheim Real Estate Limited | Real estate | 2021 |
| Jacksons Business Services Limited | Professional & scientific | 2002 |
| Jacksons Farm and Forest Ltd | Agriculture & fishing | 2014 |
| Jaco Barbers Limited | Other services | 2025 |
| Jacob Building Services Ltd | Construction | 2011 |
| Jacob Catering Ltd | Hospitality | 2025 |