| Jhsl Property Limited | Construction | 2025 |
| JJM64 Healthcare Limited | Health & social care | 2024 |
| Jjmcc Ltd | Other services | 2019 |
| JK LDN Ltd | Real estate | 2022 |
| Jkrk Property Limited | Real estate | 2013 |
| JKT Advisory Ltd | Professional & scientific | 2023 |
| JL Cleaning Solutions Ltd | Administrative & support | 2023 |
| JLA Mortgages Ltd | Financial services | 2017 |
| Jmac Estate Ltd | Real estate | 2022 |
| JMO Electrical Ltd | Construction | 2024 |
| Jobcoach Limited | Administrative & support | 2013 |
| John Burns Consultancy Limited | Professional & scientific | 2020 |
| John Head Agencies Limited | Administrative & support | 2003 |
| Johnson Forestry Limited | Agriculture & fishing | 2017 |
| JON Huntley Ltd | Professional & scientific | 2014 |
| Jordral Limited | Administrative & support | 2022 |
| Jose Accountancy Ltd | Professional & scientific | 2026 |
| JP Smiles Ltd | Health & social care | 2019 |
| JP Tower Detailing Ltd | Professional & scientific | 2003 |
| JPR Tiling Consultants Limited | Other services | 2012 |
| JR Shine Holdings Ltd | Real estate | 2026 |
| Jubious Ltd. | Other services | 2014 |
| July Nails Ltd | Other services | 2026 |
| Junior Builder Ltd | Construction | 2023 |
| Juss Commercial Properties Limited | Real estate | 2018 |
| Juss Properties Ltd. | Real estate | 2016 |
| JUUKO360VENTURES Limited | Professional & scientific | 2022 |
| Jyoti Limited | Other services | 2014 |
| K & K Property and Maintenance Ltd | Real estate | 2025 |
| K&D Properties Ltd | Real estate | 2021 |
| K&Q Enterprises Ltd | Hospitality | 2012 |
| Kadepama Limited | Professional & scientific | 2006 |
| Kaemabo Healthcare Ltd | Health & social care | 2023 |
| Kaga Property Ltd | Real estate | 2021 |
| Kahumbo Purley Ltd | Wholesale & retail | 2026 |
| Kaieteur Capital Limited | Professional & scientific | 2021 |
| Kakumani Limited | Real estate | 2009 |
| Kalam Holdings Ltd | Real estate | 2025 |
| Kaldewei UK Limited | Wholesale & retail | 2001 |
| Kamala Medical Consulting Limited | Health & social care | 2011 |
| Kamino Planning and Development Limited | Construction | 2015 |
| Kandol Limited | Construction | 2024 |
| Kangra Ltd | Public administration | 2024 |
| Karis Investments Limited | Health & social care | 2017 |
| Karmah Properties Limited | Real estate | 2024 |
| KB Construction Solutions Ltd | Construction | 2016 |
| Kbro Health Care Limited | Health & social care | 2021 |
| Kbro Health Ltd | Health & social care | 2014 |
| Kbro Properties Ltd | Real estate | 2021 |
| KDS Assets Limited | Real estate | 2021 |
| KDS Chem Ltd | Wholesale & retail | 2024 |
| Kdsm Properties Ltd | Real estate | 2025 |
| Kearney Associates Limited | Education | 2024 |
| Kedvik Investments Limited | Real estate | 2017 |
| Kegarmo Limited | Hospitality | 2026 |
| Keith Michaels Ltd | Financial services | 1989 |
| Kenley Skyline Ltd | Professional & scientific | 2026 |
| Kenneth Fergusson Limited | Health & social care | 2015 |
| Kensington Coffee House Limited | Real estate | 2008 |
| KEY2CONSULTING Limited | Professional & scientific | 2016 |
| Keypro Real Estate Ltd | Construction | 2024 |
| Keys to House Ltd | Real estate | 2024 |
| Keywhites Limited | Professional & scientific | 2018 |
| KG Andradi Ltd | Real estate | 2023 |
| KH Medical Recruitment Ltd | Administrative & support | 2024 |
| Khalpeys Frozen Food Ltd | Wholesale & retail | 2020 |
| Khine X Cyber Ltd | Administrative & support | 2024 |
| Khushi Media Limited | Administrative & support | 2019 |
| Kikibrix Ltd | Real estate | 2020 |
| King Estate Solutions Ltd | Real estate | 2026 |
| Kingdom of Desserts Ltd | Manufacturing | 2023 |
| Kings Court (Purley) Management Company Limited | Households | 2020 |
| Kingston Thames LP | | 2010 |
| Kingsviews Associates Limited | Financial services | 2015 |
| Kintechi Limited | Information & communication | 2014 |
| Kints Medicals Ltd | Health & social care | 2014 |
| Kirk Enterprise Estates Ltd | Real estate | 2021 |
| Kitazono Property Limited | Financial services | 2008 |
| Kitchener London Limited | Wholesale & retail | 2025 |
| KJ Housing Limited | Real estate | 2024 |
| Kjoseph Ltd | Administrative & support | 2019 |
| KJS Touch Ltd | Hospitality | 2022 |
| KK Construction Services Limited | Construction | 2023 |
| KK Consultant London Limited | Hospitality | 2026 |
| KKR Housing Limited | Real estate | 2025 |
| KL JJ LLP | | 2023 |
| Klariti Ltd | Professional & scientific | 2025 |
| KLM Mortgage Solutions Ltd | Financial services | 2024 |
| KLS Media Ltd | Information & communication | 2019 |
| KM Ventures Limited | Information & communication | 2004 |
| KNM3 Ltd | Real estate | 2019 |
| Knoll Care Ltd | Health & social care | 2017 |
| Kodad Properties Limited | Real estate | 2024 |
| Komal Healthcare Limited | Health & social care | 2019 |
| Konrad Construction Service Ltd | Construction | 2022 |
| Korskof Change Solutions Limited | Administrative & support | 2013 |
| Kortex Media Ltd | Information & communication | 2024 |
| KPG Property Limited | Real estate | 2023 |
| Kpgp Limited | Health & social care | 2015 |
| Kree Group Ltd | Manufacturing | 2025 |