| JWG Epps Ltd | Professional & scientific | 2023 |
| Jwill Investment Limited | Real estate | 2024 |
| JWL Flooring Limited | Administrative & support | 2019 |
| Jwsi Property Limited | Administrative & support | 2024 |
| K & a Commercial Cleaning Limited | Households | 2013 |
| K & B Plumbing and Heating Limited | Construction | 2016 |
| K & J Harper Limited | Other services | 2015 |
| K & S UK Property Ltd | Real estate | 2016 |
| K and G Alflatt Family Ventures Limited | Financial services | 2025 |
| K F Electrical Limited | Professional & scientific | 2007 |
| K G F Solutions Limited | Manufacturing | 2023 |
| K R Electrical Installations Limited | Construction | 2022 |
| K TEC Plumbing & Drainage Limited | Administrative & support | 2007 |
| K Z M Fryers Ltd | Hospitality | 2019 |
| K-Tech London Limited | Wholesale & retail | 2026 |
| K.C. Ware Building Service Design Ltd. | Construction | 2011 |
| K.I.T Cleaning Services Limited | Administrative & support | 2024 |
| K.J.L. Management Ltd. | Hospitality | 2016 |
| K.P. Finch Roofing Contractors Limited | Construction | 2009 |
| Kabayan Taxi Services Limited | Transport & logistics | 2022 |
| Kabina Limited | Construction | 2014 |
| Kade GAS Services Limited | Other services | 2014 |
| Kads Property Solutions Limited | Construction | 2025 |
| Kaft Investment Ltd | Real estate | 2018 |
| Kaft Invests Ltd | Real estate | 2014 |
| KAIKEIRAN21 Carpentry Ltd | Manufacturing | 2025 |
| Kair Ventilation Limited | Manufacturing | 1997 |
| Kale Paint and Building Materials Limited | Wholesale & retail | 2020 |
| Kalina 2026 Limited | Administrative & support | 2026 |
| Kalina Services Ltd | Administrative & support | 2022 |
| Kallar Group Limited | Construction | 2023 |
| Kallar Investments Limited | Real estate | 2003 |
| Kallar View Construction Limited | Construction | 2007 |
| Kallar View Construction Midas Limited | Construction | 2021 |
| Kallars Limited | Real estate | 2011 |
| Kallarview Developments Limited | Construction | 2017 |
| Kallarview Group Limited | Extraterritorial | 2023 |
| Kallarview Holdings Limited | Extraterritorial | 2023 |
| Kallarview Homes Limited | Real estate | 2006 |
| Kalle & Sons Limited | Real estate | 2025 |
| Kamp Partnership Limited | Real estate | 2021 |
| Kanan Property Ltd | Real estate | 2023 |
| Kanci Ltd | Administrative & support | 2025 |
| Kandola Property Limited | Construction | 2024 |
| Kantara Bay Ltd | Real estate | 2017 |
| Kanth (London) Limited | Professional & scientific | 2017 |
| Kanth Manufacturing Limited | Administrative & support | 2021 |
| Kaos Europe Limited | Transport & logistics | 1991 |
| Kapal Bhairav Technologies Limited | Information & communication | 2025 |
| Kapinara Properties Limited | Real estate | 2017 |
| KAR Rail Limited | Construction | 2019 |
| Kartex Catering Ltd | Hospitality | 2025 |
| Kasun Limited | Health & social care | 2017 |
| KAT Utilities Limited | Construction | 2013 |
| Kate Miller Ltd | Professional & scientific | 2021 |
| Kayla's Bar & Kitchen Ltd | Hospitality | 2016 |
| Kaylarry Limited | Real estate | 2022 |
| Kbar Solutions Ltd | Information & communication | 2024 |
| Kbsl Maintenance Ltd | Administrative & support | 2015 |
| KCU Properties Ltd | Real estate | 2021 |
| KDA Investments Limited | Financial services | 2017 |
| Kdhb Investments Limited | Financial services | 2017 |
| KDK Properties Limited | Real estate | 2019 |
| Kdke Maintenance Ltd | Real estate | 2021 |
| Kebab Planet Limited | Hospitality | 2018 |
| Kecs Investments Limited | Real estate | 2016 |
| Kecs Property Limited | Real estate | 2013 |
| Keddles Gym Limited | Arts & recreation | 2016 |
| Keepers Designs Limited | Construction | 1999 |
| KEF Windows & General Cleaning Ltd | Administrative & support | 2007 |
| KEG to TAP Services Ltd | Hospitality | 2014 |
| Keith Humphreys Limited | Construction | 2016 |
| Kelly Investment Properties LLP | | 2018 |
| Kelpis Shoes Limited | Other services | 2007 |
| Kelvin Engineering Limited | Wholesale & retail | 2012 |
| Kemaloglulari Limited | Real estate | 2018 |
| Kemp Consultancy Limited | Administrative & support | 2014 |
| Kemrash Health Consulting Ltd | Health & social care | 2024 |
| Ken's Fish Bar (Dulwich) Limited | Hospitality | 2011 |
| Kenny D Limited | Real estate | 2025 |
| Kenon UK Services, Ltd | Professional & scientific | 2014 |
| Kensington Mums Ltd | Professional & scientific | 2013 |
| Kent Auto Centre Ltd | Wholesale & retail | 2008 |
| Kent Building Group Ltd. | Construction | 2023 |
| Kent Chauffeurs Ltd | Professional & scientific | 2011 |
| Kent Cookery School Limited | Arts & recreation | 2023 |
| Kent Cooling Solutions Limited | Energy | 2013 |
| Kent Plant and Tools Limited | Professional & scientific | 2013 |
| Kent Power Limited | Manufacturing | 2021 |
| Kent Residential Limited | Real estate | 2022 |
| Kent Supreme Heating Ltd | Energy | 2014 |
| Kent Systems Ltd | Professional & scientific | 2026 |
| Kentedge Limited | Information & communication | 2018 |
| Kenton Property Services Limited | Real estate | 2010 |
| Keratify Limited | Professional & scientific | 2018 |
| Kerty Design Ltd | Administrative & support | 2024 |
| Keston Country Club Limited | Real estate | 1928 |
| Keston Park (1975) Limited | Households | 1975 |
| Keston Park Estates Limited | Real estate | 1923 |
| Key Property Consultants Limited | Real estate | 2014 |