| JJ Collect Limited | Administrative & support | 2011 |
| JJ COX Publishing Ltd | Information & communication | 2017 |
| Jjbrown’S Homes Limited | Construction | 2023 |
| JK Construction (Hampshire) Limited | Construction | 2015 |
| JK Roshan Ltd | Real estate | 2022 |
| JK Roshan Properties Limited | Real estate | 2022 |
| JM Thorburn Limited | Administrative & support | 2021 |
| John Gregory Construct Ltd | Construction | 2025 |
| Johnson Brothers Roofing & Construction Ltd | Construction | 2020 |
| Johnson Brothers Roofing Ltd | Construction | 2012 |
| Johnson Brothers Roofing Maintenance Ltd | Construction | 2023 |
| Johnson Properties South Ltd | Real estate | 2025 |
| Jokruger International Limited | Administrative & support | 2011 |
| JPA Trades Ltd | Wholesale & retail | 2024 |
| JPK Electrical Contractors Limited | Energy | 2012 |
| JPL IT Consultancy Limited | Information & communication | 2010 |
| JPT Properties Limited | Real estate | 2020 |
| Jumpstart Trading Ltd | Wholesale & retail | 2023 |
| Just Peachy Things Ltd | Wholesale & retail | 2026 |
| JV Ventures Limited | Construction | 2018 |
| K&D Symons Financial Services Ltd | Professional & scientific | 2013 |
| K.G. Living Limited | Professional & scientific | 2025 |
| K.I.D. Contractors Ltd | Construction | 2016 |
| K9 Metropolitan Specialists Ltd | Administrative & support | 2020 |
| Kafcd Ltd | Transport & logistics | 2022 |
| Kaloah Ltd | Wholesale & retail | 2025 |
| Karen Harrison Curtain Design Limited | Other services | 2021 |
| Karl Thyer Designs Ltd | Professional & scientific | 2019 |
| Katmon Business Services Limited | Extraterritorial | 2013 |
| KDN3D Limited | Manufacturing | 2024 |
| KDT Dog Grooming Ltd | Other services | 2023 |
| Keen Dream Events Limited | Administrative & support | 2021 |
| Kennedy Brickwork & Construction Ltd | Construction | 2025 |
| Kensingtonandlondonflatroofing Ltd | Extraterritorial | 2021 |
| Kenway Ltd. | Construction | 2000 |
| Kenway Timber and Damp [Essex] Ltd | Construction | 2009 |
| Keppler & Co Limited | Other services | 2017 |
| Kevin Herbert Limited | Construction | 2022 |
| Kevina Property Limited | Real estate | 2023 |
| Keyholding Response Ltd. | Administrative & support | 1996 |
| KG Insight Ltd | Professional & scientific | 2024 |
| KG Mortgage Services Limited | Financial services | 2012 |
| Kidzstart Sports Ltd | Education | 2020 |
| Kimana Limited | Professional & scientific | 2005 |
| Kingfisher Roofing (South) Ltd | Construction | 2023 |
| Kingsfield Electrical Limited | Construction | 2026 |
| Kive Media Limited | Information & communication | 2020 |
| KJK Properties Ltd | Households | 2024 |
| Kkbm Building Surveyors Ltd | Other services | 2018 |
| KKM Estate Limited | Real estate | 2024 |
| Kmac Digital Ltd | Professional & scientific | 2023 |
| Knightway Associates Ltd | Administrative & support | 2022 |
| Kordya Ltd | Information & communication | 2023 |
| Kresinc Psychology Ltd | Health & social care | 2023 |
| Krishna (Ckaf) Ltd | Hospitality | 2017 |
| KRP Consulting Engineers Limited | Professional & scientific | 2010 |
| L & S Medical Limited | Health & social care | 2022 |
| Lambourn Property Services Ltd | Construction | 2015 |
| Lanson Travel Limited | Administrative & support | 2015 |
| Lauguico Physiotherapy Group Limited | Other services | 2026 |
| Laurienna Limited | Financial services | 2020 |
| Lavin Weston Ltd | Information & communication | 2003 |
| Lawnscience Thames Valley Ltd | Administrative & support | 2025 |
| LCK Property Services Ltd | Real estate | 2021 |
| LE Cheminant International Ltd | Professional & scientific | 2023 |
| Legend Sandhurst Ltd | Other services | 2020 |
| Legendary Lettings Ltd | Real estate | 2014 |
| LES Davis Enterprises Ltd | Real estate | 2005 |
| Lilibets of Windsor Limited | Extraterritorial | 2020 |
| Limbcare Limited | Health & social care | 2010 |
| Lines DEV Ltd. | Information & communication | 2025 |
| Little Legends Parties Ltd | Arts & recreation | 2025 |
| LJW Marketing Limited | Information & communication | 2025 |
| Logicsor Limited | Transport & logistics | 2025 |
| Loki Kitchen Limited | Hospitality | 2015 |
| Lomas Linkhill Ltd | Professional & scientific | 2013 |
| London Products Ltd | Wholesale & retail | 2019 |
| Longlea House Limited | Health & social care | 2025 |
| Looplli Ltd | Professional & scientific | 2026 |
| Lucy O’Sullivan Integrative Therapy Ltd | Health & social care | 2022 |
| Lumoa Ltd | Information & communication | 2016 |
| LUX Motor Berkshire Ltd | Wholesale & retail | 2023 |
| LWM Air Conditioning Ltd | Construction | 2022 |
| M a Fitness Ltd | Arts & recreation | 2019 |
| M Lilly Property Limited | Real estate | 2017 |
| M.Ega.Watts Ltd | Construction | 2018 |
| Macht House Limited | Wholesale & retail | 2021 |
| MAID2CLEAN Basingstoke Ltd | Other services | 2017 |
| Mainly Books Limited | Wholesale & retail | 2013 |
| Maloney Property Group Ltd | Real estate | 2026 |
| Mani and Parm Property Ltd | Real estate | 2022 |
| Marc Chapman Ltd | Construction | 2025 |
| Mark Lilly Property Holdings Limited | Financial services | 2021 |
| Mark One Performance Ltd | Education | 2024 |
| Marshall Inov Limited | Information & communication | 2025 |
| Marspe Services Limited | Other services | 2011 |
| Martin (Eton) Limited | Real estate | 1962 |
| Martina Wren Beauty Ltd | Other services | 2025 |
| Masala Magic Sandhurst Ltd | Hospitality | 2026 |
| Masala Magic Spice Ltd | Hospitality | 2025 |