| Kesslerboy Productions Limited | Information & communication | 2007 |
| Kestrel Roofing & Building Ltd | Construction | 2021 |
| KEW Crescent Ltd | Real estate | 2024 |
| Key Trade&Consult Limited | Professional & scientific | 2021 |
| Key Training Investments Limited | Professional & scientific | 2008 |
| Key Training Limited | Education | 1977 |
| Keyani Ltd | Real estate | 2014 |
| Keycrox Ltd | Wholesale & retail | 2021 |
| Keysfield Ltd | Construction | 2021 |
| KGK Surrey Ltd | Other services | 2016 |
| Kgmg Accountancy Ltd | Financial services | 2012 |
| KH & Sons Enterprises Ltd | Wholesale & retail | 2024 |
| Kh&Sons Services Ltd | Wholesale & retail | 2024 |
| Khalid Enterprises Ltd | Health & social care | 2017 |
| Khan's Xpress Ltd | Wholesale & retail | 2024 |
| Khanalyze Financials Limited | Wholesale & retail | 2024 |
| KHIARAZAROVA1328 Ltd | Arts & recreation | 2026 |
| KHT (UK) Limited | Wholesale & retail | 2009 |
| Khyati Consultancy Limited | Information & communication | 2011 |
| Kica Union Limited | Construction | 2013 |
| Kiddi Business Ltd | Hospitality | 2022 |
| Kidstudio Ltd | Wholesale & retail | 2023 |
| Kidsverse UK Ltd | Wholesale & retail | 2019 |
| Kier Parkman GB Limited | Professional & scientific | 2025 |
| KIK Services Limited | Construction | 2008 |
| Kilmar Company Limited | Real estate | 2021 |
| Kilmar Developments Ltd | Real estate | 2017 |
| Kilmar Group London Limited | Real estate | 2021 |
| Kilmar Group Ltd | Construction | 2021 |
| Kilmar Holdings Ltd | Real estate | 2018 |
| Kilmar Homes Limited | Construction | 2025 |
| Kilmar House Limited | Real estate | 2022 |
| Kilmar Investments Limited | Real estate | 2015 |
| Kilmar Properties Limited | Real estate | 2000 |
| Kinas Carpentry Ltd | Construction | 2021 |
| Kinash Limited | Construction | 2012 |
| Kinda Solutions Ltd | Administrative & support | 2025 |
| Kinder Wellbeing Homes Limited | Real estate | 2021 |
| Kindling BIO Ltd | Professional & scientific | 2025 |
| Kinetic Coaching in Sport Limited | Arts & recreation | 2011 |
| Kinetic Foundation | Arts & recreation | 2012 |
| Kingdon House Ltd | Information & communication | 2025 |
| Kingfisher Court (Sutton) Management Company Limited | Households | 1984 |
| Kingfisher House Residents Association (Trematon Place) Limited | Real estate | 1991 |
| Kings Meadow Homes Ltd | Construction | 2017 |
| Kingsbridge Living Limited | Construction | 2005 |
| Kingsley Nicholas & Ward Limited | Administrative & support | 1991 |
| Kingston and Wimbledon Black Taxi Centre Limited | Transport & logistics | 2002 |
| Kingston Contractors Ltd | Construction | 2012 |
| Kingston EYE Centre Limited | Health & social care | 2003 |
| Kingston Medical Ltd | Health & social care | 2012 |
| Kingston Valeting Limited | Wholesale & retail | 2019 |
| Kingswood Law Limited | Professional & scientific | 2019 |
| Kippa BID Limited | Other services | 2009 |
| Kipu Education Ltd | Education | 2024 |
| Kiran Capital Ltd | Real estate | 2013 |
| Kirby's Management Services Limited | Professional & scientific | 2015 |
| Kirk Rise Residents Association Limited | Households | 1989 |
| Kiruban Properties Management Ltd | Administrative & support | 2017 |
| Kisambira Ltd | Health & social care | 2015 |
| Kisiel Hire Ltd | Administrative & support | 2012 |
| Kisiel Ltd. | Construction | 2007 |
| Kisiel Piling Ltd | Construction | 2021 |
| Kisl Limited | Professional & scientific | 2014 |
| Kiss Wealth Limited | Other services | 2011 |
| Kiwi MOA Limited | Administrative & support | 2019 |
| KJ Investment Properties Limited | Real estate | 2022 |
| Kjdm Performance Club Ltd | Other services | 2023 |
| Kjej Properties Limited | Real estate | 2025 |
| Kk&Mc Creative Ltd | Construction | 2021 |
| KKB Consultancy Limited | Professional & scientific | 2015 |
| Kkraft Events Ltd | Administrative & support | 2019 |
| Kkvrr Limited | Real estate | 2023 |
| KL Business Developers Ltd | Professional & scientific | 2025 |
| KL RT LLP | | 2024 |
| KLE014 Services Ltd | Administrative & support | 2014 |
| KLL Express Limited | Hospitality | 2009 |
| KLM Engineering Consulting Ltd | Professional & scientific | 2014 |
| Klorenz Ltd. | Manufacturing | 2025 |
| KM Artist Ltd | Other services | 2023 |
| Kmgg Limited | Real estate | 2015 |
| KMI London Ltd | Construction | 2005 |
| KMK Maintenance Ltd | Construction | 2023 |
| KML Analytics Limited | Information & communication | 2024 |
| Kmml Communications Ltd | Information & communication | 2019 |
| KMP Design Limited | Construction | 2023 |
| KMS Property Management Limited | Real estate | 2021 |
| Kmsf Limited | Administrative & support | 2026 |
| KN RAJ Sutton Limited | Hospitality | 2021 |
| KN Sons Supermarket Ltd | Wholesale & retail | 2024 |
| Knead N NAP Ltd | Hospitality | 2025 |
| Knead to Know Consultancy Ltd | Professional & scientific | 2020 |
| Knightsbridge Valet Services Limited | Other services | 2019 |
| Knithomay Ltd | Construction | 2025 |
| KNK Developments Limited | Real estate | 2025 |
| KNL Cares Ltd | Health & social care | 2021 |
| KNM Studio Ltd | Professional & scientific | 2022 |
| KNN Project Management Office Ltd | Information & communication | 2014 |
| Knole Mews Freehold Management Company Limited | Households | 2022 |
| Knowab Ltd | Water & waste | 2015 |