| J&S Food Services Ltd | Wholesale & retail | 2023 |
| J&S Plastering Ltd | Construction | 2014 |
| J&T Services Limited | Professional & scientific | 2014 |
| J. & G. Hollingsworth Limited | Administrative & support | 1986 |
| J. Dodd & Co. Limited | Wholesale & retail | 1980 |
| J. Garside Limited | Professional & scientific | 2002 |
| J. S. Repairs Limited | Other services | 2002 |
| J.Atkinson Electrical Ltd | Construction | 2025 |
| J.B. Real Estate Limited | Construction | 2002 |
| J.B.Schofield & Sons Limited | Wholesale & retail | 1964 |
| J.E.C. Investment Company Limited | Real estate | 1957 |
| J.E.D Mechanical Services Limited | Professional & scientific | 2020 |
| J.I.T.A. Properties Limited | Real estate | 2010 |
| J.Ivie Plasterers Ltd | Construction | 2020 |
| J.J. Bookkeeping Services Limited | Professional & scientific | 2024 |
| J.L. Albutt Limited | Construction | 2004 |
| J.L.R. Garages Limited | Wholesale & retail | 1998 |
| J.Lam Engineering Ltd | Professional & scientific | 2025 |
| J.M. Building Services Limited | Construction | 1994 |
| J.M. Northern Limited | Real estate | 1998 |
| J.S. Haverly Limited | Wholesale & retail | 2020 |
| J.S. Movers UK Ltd | Transport & logistics | 2020 |
| J.W Solar Ltd | Construction | 2023 |
| J.W.L & J.R PUB Group Ltd | Hospitality | 2025 |
| J.Z 101 Ltd | Wholesale & retail | 2025 |
| JA ELL Ltd | Real estate | 2025 |
| JA Healthcare Services Limited | Health & social care | 2023 |
| JA Zaiqa Ltd | Hospitality | 2025 |
| Jaae Ltd | Wholesale & retail | 2026 |
| JAAS13 Limited | Real estate | 2026 |
| Jabb Services Ltd | Administrative & support | 2025 |
| Jaber’S Keep Warm Ltd | Construction | 2022 |
| Jabsnett Data Solutions Ltd | Administrative & support | 2011 |
| JAC Aviation Ltd | Transport & logistics | 2022 |
| Jacamast Developments Limited | Construction | 2024 |
| Jacamast Group Limited | Financial services | 2024 |
| Jacamast Holdings Limited | Financial services | 2024 |
| Jacamast Services Limited | Manufacturing | 1991 |
| Jacamast Structureclad Limited | Construction | 1994 |
| Jack & Jill Removals Limited | Transport & logistics | 2015 |
| Jack & Jill's Nursery Ltd | Education | 1996 |
| Jack Davison Limited | Wholesale & retail | 2025 |
| Jack Downes Plumbing and Heating Limited | Construction | 2021 |
| Jack G Building Limited | Construction | 2023 |
| Jack Shutt Cricket Coaching Limited | Arts & recreation | 2024 |
| Jacks & Co Properties Ltd | Real estate | 2025 |
| Jackson Squirrels Ltd | Real estate | 2023 |
| Jacob Brian (Leeds) Ltd | Wholesale & retail | 2021 |
| Jacob Brian Ltd | Wholesale & retail | 2021 |
| Jacob Buchanan Ltd | Extraterritorial | 2021 |
| Jacrac Display Limited | Manufacturing | 2009 |
| Jadd PVT Ltd | Health & social care | 2017 |
| Jade Homes Construction Limited | Construction | 2015 |
| Jade Homes Properties Limited | Real estate | 2018 |
| Jade Homes Redditch Limited | Construction | 2022 |
| Jade Tree Designs Ltd | Wholesale & retail | 2021 |
| JADE3 Architecture Ltd | Professional & scientific | 2010 |
| Jaden P Ltd | Wholesale & retail | 2025 |
| Jaes Interiors Limited | Professional & scientific | 2020 |
| JAF Trichology Ltd | Other services | 2018 |
| Jaffier Enterprise Ltd | Real estate | 2025 |
| Jaibow Campers Ltd | Construction | 2014 |
| JAK Prestige Ltd | Wholesale & retail | 2022 |
| Jakes Motors Ltd | Wholesale & retail | 2022 |
| Jalebi FM Ltd | Information & communication | 2024 |
| JAM Film Productions Ltd | Information & communication | 2021 |
| JAM Housing Ltd | Real estate | 2024 |
| JAM Rental Huddersfield Ltd | Real estate | 2020 |
| JAM Sports Management Limited | Arts & recreation | 2019 |
| Jamaica School Resources | Education | 2008 |
| Jamal Deen Properties Ltd | Real estate | 2025 |
| Jambala Global Ltd | Real estate | 2016 |
| Jamber Holdings Ltd | Real estate | 2025 |
| James Brindley Construction Ltd | Construction | 2015 |
| James Clay & Sons Limited | Extraterritorial | 2019 |
| James Gough Ltd | Financial services | 2014 |
| James Grace Associates Limited | Administrative & support | 2018 |
| James Grace Local Limited | Administrative & support | 2021 |
| James Grace Technical Limited | Administrative & support | 2021 |
| James Holdsworth & Brothers Group Limited | Manufacturing | 1933 |
| James Manhertz Transport Ltd | Transport & logistics | 2018 |
| James Robinson Group Ltd | Financial services | 2018 |
| James Robinson Speciality Ingredients Ltd | Manufacturing | 1901 |
| James Robson Ultrasound Services Ltd | Health & social care | 2022 |
| James Whitham Racing Limited | Arts & recreation | 2022 |
| Jamesmobas Limited | Health & social care | 2021 |
| Jamm Projects Ltd | Information & communication | 2014 |
| Jams Facility Services Ltd | Administrative & support | 2021 |
| JAN Developments Ltd | Administrative & support | 2017 |
| Jane at Blossom Limited | Health & social care | 2025 |
| Jane Simpson Access Ltd | Professional & scientific | 2008 |
| Jane Walks Dogs Ltd | Other services | 2022 |
| Janet Murphy Driving School Ltd | Education | 2013 |
| Janethovers Cleaning Limited | Administrative & support | 2021 |
| Jang Investments Ltd | Wholesale & retail | 2026 |
| Janine Milner Beauty Ltd | Other services | 2016 |
| Jannat Boutique Limited | Wholesale & retail | 2022 |
| Jannat Restaurant Ltd | Hospitality | 2025 |
| Jannat Styles Ltd | Wholesale & retail | 2026 |
| Jannat Tours UK Limited | Administrative & support | 2023 |