| J.R. Foster (Haulage) Limited | Transport & logistics | 1995 |
| J.Ranu Transport Limited | Transport & logistics | 2025 |
| J.Robinson(Burton-On-Trent)Limited | Professional & scientific | 1923 |
| J.S Bindra Consultancy Ltd | Professional & scientific | 2019 |
| J.S. Building Services Limited | Construction | 1981 |
| J.S. Hothi Limited | Health & social care | 2023 |
| J.S. Spooner Contracts Limited | Manufacturing | 2007 |
| J.S.D. Polishers Limited | Manufacturing | 2003 |
| J.S.P. Financial Services Limited | Financial services | 1991 |
| J.S.R. Spirits Limited | Manufacturing | 2024 |
| J.S.Wright & Co. Holdings Limited | Professional & scientific | 2016 |
| J.S.Wright & Co.Limited | Construction | 1936 |
| J.T Caterers Ltd | Hospitality | 2022 |
| J.T. Flowers (Pipework & Heating) Limited | Construction | 1986 |
| J.T.Motors MOT Station Limited | Wholesale & retail | 2012 |
| J.Tech Car and Commercial Repairs Ltd | Wholesale & retail | 2025 |
| J.W.Rudge & Co.Limited | Manufacturing | 1958 |
| J1000 Ltd | Financial services | 2024 |
| J11TGA Limited | Financial services | 2024 |
| J13 Mot's Ltd | Wholesale & retail | 2018 |
| J2 Consulting Limited | Information & communication | 1996 |
| J2 Events Management Ltd | Other services | 2015 |
| J2 Healthcare Limited | Real estate | 2002 |
| J2911 Ltd | Information & communication | 2024 |
| J2B Cleaning Ltd | Administrative & support | 2023 |
| J2M Concepts Services Ltd | Hospitality | 2019 |
| J3 Builders Limited | Construction | 2020 |
| J3 Services Ltd | Administrative & support | 2025 |
| J4L Store 1 Limited | Manufacturing | 2026 |
| J4S Ltd | Administrative & support | 2024 |
| J6 Homes Limited | Real estate | 2016 |
| J6 Investments Ltd | Construction | 2016 |
| J6 Property Partners Ltd | Real estate | 2020 |
| J7 Builders Ltd | Construction | 2017 |
| JA & BS Faridrad Ltd | Extraterritorial | 2012 |
| JA & Co London Limited | Wholesale & retail | 2015 |
| JA & Company Accountants Limited | Professional & scientific | 2002 |
| JA Catering Ltd | Hospitality | 2025 |
| JA Child Minding Services Limited | Health & social care | 2016 |
| JA Engineering Consultancy Limited | Professional & scientific | 2025 |
| JA Housing Developments Ltd. | Construction | 2018 |
| JA Pharm Ltd | Health & social care | 2019 |
| JA Prime Estates Ltd | Real estate | 2023 |
| JA Property and Management Ltd | Real estate | 2022 |
| Ja&Ia Consultants Ltd | Other services | 2017 |
| Ja-More Management Solutions Limited | Professional & scientific | 2023 |
| JA1 8AAD Property Limited | Real estate | 2022 |
| JA9 Limited | Administrative & support | 2025 |
| Jaan Investments Ltd | Financial services | 2022 |
| Jaas 15 Investments Limited | Real estate | 2026 |
| JAB Driving Limited | Transport & logistics | 2025 |
| JAB Home Improvements Ltd | Professional & scientific | 2017 |
| JAB PMS Limited | Real estate | 2017 |
| JAB Project Solutions Ltd | Professional & scientific | 2026 |
| JAB Property Investments Limited | Real estate | 2022 |
| JAB Trading Limited | Hospitality | 2025 |
| Jabal AL Quwa Ltd | Wholesale & retail | 2023 |
| Jabal Limited | Other services | 2017 |
| Jabar Studios Ltd | Information & communication | 2026 |
| Jabbar Juice Limited | Hospitality | 2026 |
| Jabed Transport Ltd | Transport & logistics | 2026 |
| Jabel Alrajaf Services Limited | Other services | 2020 |
| Jabr Ltd | Professional & scientific | 2024 |
| JABRANM7 Ltd | Administrative & support | 2026 |
| Jabula PVT Ltd | Health & social care | 2020 |
| Jabz Hair and Cosmetics Leeds Limited | Other services | 2025 |
| JAC Fabrics Limited | Manufacturing | 2025 |
| Jacar Cleaning and Other Services Ltd | Administrative & support | 2022 |
| Jace Bakery Limited | Wholesale & retail | 2025 |
| Jacey’S Cafe’ Ltd | Hospitality | 2024 |
| Jack & Williams Limited | Real estate | 2024 |
| Jack Briggs (Investments) Limited | Real estate | 1964 |
| Jack Empires PVT Ltd | Health & social care | 2013 |
| Jack Masters Limited | Manufacturing | 1987 |
| Jack the Plumber Ltd | Extraterritorial | 2021 |
| Jack the Tiler Limited | Construction | 2024 |
| Jack Therapy Ltd. | Public administration | 2015 |
| Jack's Furniture Limited | Wholesale & retail | 2019 |
| Jackbuild Limited | Construction | 2020 |
| Jackcorp Ltd | Arts & recreation | 2017 |
| Jackery UK Ltd | Wholesale & retail | 2020 |
| Jacklee Property Holdings Ltd | Real estate | 2025 |
| Jackryan.Corp Ltd | Transport & logistics | 2023 |
| Jacks & Juices Ltd | Hospitality | 2025 |
| Jacks Heating & Plumbing Ltd | Construction | 2018 |
| Jacks WOK Ltd | Hospitality | 2023 |
| Jacks.W Builder Ltd | Construction | 2026 |
| Jackson Accounting Services Limited | Professional & scientific | 2024 |
| Jackson C & J Ltd | Manufacturing | 2017 |
| Jackson Psychology Associates Ltd | Education | 2022 |
| Jackson Way Properties Limited | Construction | 1993 |
| Jackson Webb Limited | Professional & scientific | 2014 |
| Jackson Woodlands LLP | | 2018 |
| Jackson Workplace Solutions Limited | Information & communication | 2025 |
| Jackson's,(Tenbury)Limited | Real estate | 1948 |
| Jacksons Garage (Birmingham) Limited | Real estate | 1975 |
| Jacksons Garden Supplies Limited | Wholesale & retail | 2016 |
| Jacksons Jewellery Limited | Other services | 1996 |
| Jacksons Recovery (Holdings) Limited | Professional & scientific | 2012 |
| Jacksons Recovery Limited | Transport & logistics | 2001 |