| J P Correia Design & Build Limited | Construction | 2015 |
| J P Ferreira Creative Ltd | Other services | 2016 |
| J Plumbing & Heating Ltd | Construction | 2025 |
| J R Popat International Management Ltd | Professional & scientific | 2020 |
| J S Utilities South Ltd | Construction | 2023 |
| J Shah Consulting Limited | Information & communication | 2010 |
| J Steers Carpentry Ltd | Construction | 2017 |
| J Thibaut Consultancy Services Limited | Professional & scientific | 2010 |
| J-Communications Ltd | Information & communication | 2017 |
| J-Secure Ltd | Information & communication | 2015 |
| J. Schembri & Co Ltd | Administrative & support | 2003 |
| J.A.L. Chemicals Limited | Wholesale & retail | 2004 |
| J.H.J. Banstead Ltd | Wholesale & retail | 2024 |
| J.I.S. Services Limited | Professional & scientific | 2003 |
| J.M and Sons Electrical Installations Ltd | Construction | 2021 |
| J.P.R. Business Limited | Wholesale & retail | 2003 |
| J.R. Service (Tadworth) Ltd | Wholesale & retail | 2018 |
| J.T.Hunt(Aquapets)Limited | Wholesale & retail | 1963 |
| J2 United Ltd | Other services | 2016 |
| Jabina Limited | Wholesale & retail | 2020 |
| Jack Auletta Limited | Construction | 2006 |
| Jack Finnerty Design Ltd | Professional & scientific | 2015 |
| Jack Frost Screen Protectors Ltd | Manufacturing | 2017 |
| Jack Sprat Management & Events Limited | Hospitality | 2018 |
| Jackie Adams Consulting Limited | Administrative & support | 2017 |
| Jackie Quinn & Co. Ltd. | Real estate | 1995 |
| Jackie Quinn Estate Agents Limited | Real estate | 2015 |
| Jacks & Wang Limited | Real estate | 2023 |
| Jackson Noon Estate Agents Ltd | Real estate | 2011 |
| Jacq OUT the Box Limited | Other services | 2011 |
| Jacquemonti Partners Ltd | Administrative & support | 2025 |
| Jacqui Skinner Consulting Limited | Professional & scientific | 2013 |
| Jade Nails Limited | Other services | 2014 |
| Jagdish Snacks UK Limited | Wholesale & retail | 2019 |
| Jahanara Limited | Health & social care | 2016 |
| Jaibuildserve Ltd | Mining & quarrying | 2025 |
| Jalure Ltd | Health & social care | 2016 |
| James B Squirrell Limited | Construction | 2008 |
| James Brook Private Clients Ltd | Professional & scientific | 2023 |
| James Garside Planning Limited | Professional & scientific | 2016 |
| James Harvey Motor Company Limited | Administrative & support | 2016 |
| James Insurance Services Limited | Financial services | 2005 |
| James Mccrone Insurance Brokers Limited | Financial services | 2006 |
| James Steiner Limited | Professional & scientific | 2014 |
| Jamesthesmith Ltd | Information & communication | 2017 |
| Jamestown Research Ltd | Financial services | 2010 |
| Jami Holdings Limited | Financial services | 2019 |
| Jamie Johnson Fitness Ltd | Arts & recreation | 2025 |
| Jamuna Housing Ltd | Professional & scientific | 2025 |
| JAN Investments Limited | Real estate | 2019 |
| Janes Wealth Planning Ltd | Financial services | 2024 |
| Janik Enterprise Ltd | Wholesale & retail | 2025 |
| Janoel Electrical Limited | Energy | 2018 |
| Jansin Ltd | Wholesale & retail | 2025 |
| Janu Properties Ltd | Real estate | 2020 |
| Janus I.T. Limited | Professional & scientific | 1998 |
| Janusha Private Limited | Real estate | 2025 |
| Janvoria Ltd | Information & communication | 2023 |
| Jarco Ltd | Administrative & support | 2025 |
| Jark Property Limited | Real estate | 2023 |
| JAS Care Homes Limited | Health & social care | 2019 |
| Jashmia Convenience Ltd | Wholesale & retail | 2017 |
| Jasmin Road Limited | Construction | 2024 |
| Jasmin Road Management Limited | Households | 2025 |
| Jasmine Project Management Limited | Administrative & support | 2017 |
| Jason Barnett Limited | Construction | 2022 |
| Jason Good Architecture Limited | Professional & scientific | 2024 |
| Jasper Estates Ltd. | Real estate | 2017 |
| Jasplanservices Limited | Professional & scientific | 2015 |
| JAV Engineering Design Limited | Professional & scientific | 2024 |
| Javed&Javaid Limited | Real estate | 2024 |
| Jawsan Limited | Construction | 2016 |
| JAX Maddison Designs Limited | Construction | 2025 |
| Jaxon Estates Ltd | Households | 2025 |
| JAY D Engineering Ltd | Other services | 2021 |
| Jayakumar and Co LLP | | 2020 |
| Jays Property Management Ltd | Real estate | 2023 |
| Jayson Panganiban Ltd | Health & social care | 2021 |
| JB - Eden Catering Limited | Manufacturing | 2020 |
| JB Damp Proofing LLP | | 2005 |
| JBS Development Solutions Ltd | Construction | 2017 |
| Jbwm Broadway Limited | Other services | 2018 |
| JC (Epsom) Limited | Real estate | 2025 |
| JC Decorating and Carpentry Services Ltd | Manufacturing | 2022 |
| JC Plumbing & Heating Maintenance Services Limited | Construction | 2014 |
| JCB Investments Ltd | Real estate | 2022 |
| Jclh Limited | Wholesale & retail | 2018 |
| JCS Consulting Ltd | Professional & scientific | 2018 |
| JD and Sons Building and Landscaping Ltd | Construction | 2026 |
| JD Moling Limited | Construction | 2019 |
| JD Residential Property Consultants Ltd | Real estate | 2017 |
| JD Roofing Specialist Ltd | Construction | 2025 |
| Jdi&R Limited | Construction | 2015 |
| JDV Tennis Ltd | Education | 2025 |
| JE Energy Consulting Ltd | Professional & scientific | 2024 |
| JE14 Limited | Professional & scientific | 2024 |
| Jealous Beauty Ltd | Other services | 2015 |
| Jeanne Consulting Limited | Professional & scientific | 2020 |
| Jeds Property Limited | Real estate | 2021 |
| Jefferson Drakeford Limited | Professional & scientific | 2007 |