| J.A. Elliss Limited | Agriculture & fishing | 1963 |
| J.C. & B. Harvey (Farmers) Limited | Agriculture & fishing | 1973 |
| J.D Properties (Lincs) Limited | Real estate | 2023 |
| J.D. Marshall Building & Maintenance Limited | Construction | 2003 |
| J.E. Porter Limited | Manufacturing | 1985 |
| J.E.Morris(Farmers)Limited | Agriculture & fishing | 1954 |
| J.E.S Sales Ltd | Wholesale & retail | 2025 |
| J.L.F Construction Ltd | Construction | 2019 |
| J.P. Wharton Limited | Construction | 2005 |
| J.Ram Cafe Ltd | Hospitality | 2024 |
| J.Ram Homemade Food Ltd | Hospitality | 2025 |
| J.Ruddock Limited | Real estate | 1917 |
| J.S.F.Hood Limited | Agriculture & fishing | 1956 |
| J.S.Highfield Limited | Transport & logistics | 1965 |
| J.Stewart Aviation Ltd | Manufacturing | 2022 |
| J.T.Hollis(Farms)Limited | Agriculture & fishing | 1951 |
| J.W. Marris & Sons Limited | Agriculture & fishing | 1976 |
| J3 Construction Services Ltd | Construction | 2023 |
| JA Andrews & Sons Limited | Wholesale & retail | 2003 |
| JA COX Heating Ltd | Construction | 2012 |
| Jabas.Ai Ltd | Information & communication | 2026 |
| Jackdaw International Ltd | Extraterritorial | 2005 |
| Jackob Trans Ltd | Transport & logistics | 2021 |
| Jackson Engineering UK Ltd | Manufacturing | 2006 |
| Jackson Living Limited | Construction | 2017 |
| Jackson Roofing Limited | Construction | 2008 |
| Jacksons Workwear Rental Limited | Wholesale & retail | 1923 |
| Jacob's DEN C.I.C. | Other services | 2023 |
| Jade DN Solutions Limited | Health & social care | 2025 |
| Jade Farrier Hawkins Limited | Hospitality | 2019 |
| JAE Consultation Ltd | Administrative & support | 2025 |
| JAF Property Ltd | Real estate | 2025 |
| Jailhouse Frock Ltd | Manufacturing | 2021 |
| Jaimar Developments Ltd | Information & communication | 2026 |
| JAK Bollan Developments Limited | Construction | 2015 |
| Jake Rigby Properties Ltd | Real estate | 2025 |
| Jake Taylor Roofing Ltd | Construction | 2026 |
| Jalapeno Ventures Ltd | Agriculture & fishing | 2018 |
| Jalousie Boutique Ltd | Wholesale & retail | 2016 |
| Jamal Hayat Ltd | Health & social care | 2017 |
| Jamauto Ltd | Administrative & support | 2016 |
| James Anderson Ltd | Professional & scientific | 2019 |
| James Andrew Electrical Limited | Construction | 2019 |
| James Conduit Ltd | Professional & scientific | 2018 |
| James COX Engineering Ltd | Manufacturing | 2021 |
| James Oliver Conservatories Limited | Construction | 2003 |
| James Oliver Direct Limited | Wholesale & retail | 2009 |
| James Proctor Ltd | Administrative & support | 2018 |
| James Property Lincs Ltd | Real estate | 2023 |
| James Ramsey Properties Ltd | Construction | 2016 |
| James Sutton Sculpture Limited | Arts & recreation | 2014 |
| James Tanner Properties Limited | Real estate | 2020 |
| James Taylor Motors Limited | Wholesale & retail | 2002 |
| James Taylor Plumbing and Heating Ltd | Construction | 2026 |
| James Wynne Limited | Wholesale & retail | 2002 |
| Jamieson Alexander Audit Limited | Professional & scientific | 2018 |
| Jamro Consulting Limited | Professional & scientific | 2008 |
| Jamson Services Ltd | Professional & scientific | 2024 |
| Janavil Ltd | Health & social care | 2018 |
| Jane L Smith Consulting Ltd | Professional & scientific | 2018 |
| Jane Means Limited | Wholesale & retail | 2013 |
| Jans Property Holdings Limited | Real estate | 2021 |
| Jargoki Ltd | Real estate | 2026 |
| Jasas Logistics Limited | Transport & logistics | 2017 |
| Jasmine N Ltd | Wholesale & retail | 2019 |
| Jason Hollingworth Limited | Wholesale & retail | 2014 |
| Jason O'Halloran Limited | Other services | 2010 |
| Jason Parker Ltd | Professional & scientific | 2021 |
| Jasper Attack Limited | Construction | 2024 |
| Jaspers Consulting Limited | Professional & scientific | 2020 |
| Jassal & Associates Ltd | Hospitality | 2025 |
| Jastira Retail Ltd | Wholesale & retail | 2025 |
| Jayjol Property Ltd | Real estate | 2026 |
| Jaykay Scaffolding Limited | Construction | 2006 |
| Jaynes Bridalwear Limited | Wholesale & retail | 2014 |
| Jays Inks Limited | Other services | 2023 |
| Jays Vehicle Movers Limited | Transport & logistics | 2018 |
| Jaysons Group Limited | Wholesale & retail | 2025 |
| Jazzcatz C.I.C. | Education | 2023 |
| Jazzicca Ltd | Information & communication | 2019 |
| JB Bodyworks (Lincoln) Limited | Wholesale & retail | 2022 |
| JB Property Sales Ltd | Real estate | 2024 |
| JB Transport Consultants Ltd | Professional & scientific | 2026 |
| JBB Lettings Limited | Other services | 2003 |
| JBD Financial Planning Limited | Financial services | 2017 |
| Jbnb Haulage Ltd | Transport & logistics | 2025 |
| JC Griffin Electrical Limited | Construction | 1997 |
| JC Holdco Ltd | Financial services | 2024 |
| JC Kosi Limited | Health & social care | 2025 |
| JC Tiling Ltd | Construction | 2022 |
| Jcap Trading Co. Ltd | Professional & scientific | 2026 |
| JCB Commercials Ltd | Transport & logistics | 2026 |
| Jcbf Limited | Real estate | 2019 |
| Jcbh Properties Limited | Real estate | 2020 |
| JCC Care in Education Limited | Health & social care | 2025 |
| JCC Group Holdings Limited | Financial services | 2025 |
| JCC Marine Limited | Administrative & support | 2025 |
| JCC Prestige Assets Limited | Administrative & support | 2025 |
| JCH Pension Management Limited | Professional & scientific | 2008 |
| JCH Wealth Management Limited | Financial services | 2026 |