| JH Designs (Interiors) Ltd. | Professional & scientific | 2018 |
| JHN Eyes Ltd | Health & social care | 2022 |
| Jill Stew Dancewear Limited | Wholesale & retail | 1988 |
| Jill Treloggen Interiors Limited | Administrative & support | 2005 |
| JJ Carpentry Services Limited | Construction | 2008 |
| JJ IT and Business Change Consulting Ltd | Information & communication | 2016 |
| JJD Publishing Limited | Professional & scientific | 2022 |
| JJL Family Holdings Limited | Financial services | 2020 |
| JK Medcomms Assistance Limited | Administrative & support | 2018 |
| JK Squared Limited | Professional & scientific | 2020 |
| JKF Services Ltd | Transport & logistics | 2025 |
| JKM Publishing Limited | Information & communication | 2016 |
| JLP (Haulage) Limited | Transport & logistics | 2007 |
| JLV Finance Limited | Administrative & support | 2012 |
| Joanne Alderson Design Limited | Professional & scientific | 2015 |
| Joannes Junior Limited | Real estate | 2021 |
| John Brown Images Limited | Information & communication | 2011 |
| John David Homes Limited | Construction | 2016 |
| John Fissenden Consultancy Ltd | Professional & scientific | 2014 |
| John Holliday Consolidated Ltd | Financial services | 2025 |
| John Spracklen (International) Limited | Construction | 1978 |
| John Wilkinson Electrical Solutions Limited | Construction | 2001 |
| Johnson & Johnson Property Group Limited | Real estate | 2023 |
| Johnson Kerswill Limited | Construction | 2016 |
| Johnsy Mobile Welding and Fabrication Services Ltd | Manufacturing | 2024 |
| Join a Link Ltd | Administrative & support | 2011 |
| Jolly Pines Limited | Agriculture & fishing | 2026 |
| Jolly Postboys Limited | Hospitality | 2016 |
| Jolly PUB Co Limited | Hospitality | 2023 |
| Jolly Sportsman Ltd | Hospitality | 2025 |
| Jolumy Limited | Real estate | 2024 |
| Joma Invest Ltd | Professional & scientific | 2024 |
| Joma Invest SPD Ltd | Real estate | 2025 |
| JON Rusk Plumbing & Heating Limited | Construction | 2021 |
| JON Warwick Ltd. | Transport & logistics | 2007 |
| Jonathan and Amanda Ford Landscape Consultants Limited | Professional & scientific | 2003 |
| Jordan Cross GAS Appliance Services Ltd. | Construction | 2018 |
| Joseph Starsmore Ltd | Professional & scientific | 2019 |
| Joseph Taylor Pianos Limited | Other services | 2010 |
| Joss Searchlight | Information & communication | 2011 |
| Journo Ltd | Information & communication | 2024 |
| JPC Accountancy Limited | Professional & scientific | 2024 |
| JPD Accountancy LLP | | 2024 |
| JPJ Creative Spaces Limited | Construction | 2024 |
| JPL Peking Express Limited | Hospitality | 2022 |
| JPL Properties and Lettings LLP | | 2025 |
| JPS Technical Services Limited | Information & communication | 2000 |
| JPS Technical UK Holdings Limited | Real estate | 2024 |
| JRD Building Developments Ltd | Real estate | 2012 |
| JRD Property Investments Ltd | Real estate | 2012 |
| JRS Painting and Decorating Ltd | Construction | 2011 |
| JS Auctions Limited | Extraterritorial | 2011 |
| JS Fine Art Limited | Wholesale & retail | 2011 |
| Jstokesvaleting Ltd | Administrative & support | 2024 |
| JTB Consulting Ltd | Information & communication | 2025 |
| Jtgv ADS Ltd | Professional & scientific | 2022 |
| JTM & Sons Ltd | Real estate | 2024 |
| Juicy Editing Ltd | Information & communication | 2012 |
| Juicy Juicy Limited | Extraterritorial | 2011 |
| Julius Huett Consultancy Limited | Other services | 2012 |
| Jupiter Aviation Ltd | Transport & logistics | 2019 |
| Jurni Leasing Limited | Extraterritorial | 2023 |
| Juro Limited | Real estate | 2007 |
| Juroton Limited | Construction | 2007 |
| Just Accounts and Tax Limited | Professional & scientific | 2013 |
| Just ASK Plumbing Limited | Construction | 2014 |
| Just Audit & Assurance Ltd | Professional & scientific | 2019 |
| Just Bookkeeping Ltd | Professional & scientific | 2020 |
| Just Business Support Ltd | Administrative & support | 2020 |
| Just Experts Ltd | Information & communication | 2025 |
| Just Fabrics Limited | Wholesale & retail | 2002 |
| Just Like Home Childminding Limited | Health & social care | 2023 |
| Just Nerds Ltd | Information & communication | 2024 |
| Just Promotional Ltd | Administrative & support | 2022 |
| Just Resources International Limited | Professional & scientific | 2000 |
| Just Right Autos Ltd | Wholesale & retail | 2022 |
| Just Sophie Interiors Ltd | Professional & scientific | 2019 |
| Just Web Design Limited | Information & communication | 2023 |
| JVF Rinascita Ltd | Information & communication | 2025 |
| JWM Partners Limited | Professional & scientific | 2024 |
| JWR Building Services Limited | Construction | 2023 |
| K Cooper Holdings Limited | Financial services | 2021 |
| K Cooper Retail Limited | Wholesale & retail | 2023 |
| K D Building & Groundworks Ltd | Construction | 2020 |
| K J Bridges Building Contractors Limited | Construction | 2008 |
| K L GUY Investments Limited | Extraterritorial | 2015 |
| K Plan Services Limited | Administrative & support | 2019 |
| K R Z Fleet Services Ltd | Transport & logistics | 2019 |
| K R Z Property Solutions Limited | Real estate | 2020 |
| K W Cooling Services Ltd | Construction | 2019 |
| K&M Leadwork Ltd | Construction | 2015 |
| K.C.Skipp Plumbing & Heating Services Ltd | Construction | 2015 |
| K.W Brickwork & Stone Specialists Limited | Extraterritorial | 2021 |
| K2R Limited | Real estate | 2021 |
| Kafue Consultants Limited | Professional & scientific | 2019 |
| Kaikam Ltd | Professional & scientific | 2024 |
| Kalas Wear Ltd | Wholesale & retail | 2013 |
| Kaleb Cooper Contracting Limited | Agriculture & fishing | 2021 |
| Kaleb Cooper Productions Limited | Information & communication | 2021 |
| Kamala Nair Inc Ltd | Arts & recreation | 2019 |