| Kart Geezer Ltd | Arts & recreation | 2021 |
| Karters Cafe Ltd | Hospitality | 2016 |
| Kasanova Properties Limited | Real estate | 2026 |
| Kash Cloud Ltd | Information & communication | 2020 |
| Katana Call Team Limited | Professional & scientific | 2019 |
| Katchick Foods Limited | Wholesale & retail | 2007 |
| Kate Cook Interiors Ltd | Professional & scientific | 2013 |
| Kater Four (Cash & Carry) Limited | Wholesale & retail | 1973 |
| Katherine Sheard Ltd | Wholesale & retail | 2023 |
| Katie B & Co. Limited | Other services | 2024 |
| Katy Wilson Property Ltd | Real estate | 2018 |
| Kawshala Peiris Ltd | Health & social care | 2019 |
| Kays Doughnuts Ltd | Hospitality | 2023 |
| KAZ Taxis Ltd | Transport & logistics | 2025 |
| Kazi Properties & Solutions Ltd | Real estate | 2025 |
| KB Bookkeeping Plus Limited | Professional & scientific | 2017 |
| KC Warewashers Ltd | Manufacturing | 2025 |
| KCI Medical Limited | Professional & scientific | 1973 |
| KCI UK Holdings Limited | Professional & scientific | 1997 |
| KCN Finance Limited | Financial services | 2020 |
| KCP Halo Consultancy Limited | Wholesale & retail | 2024 |
| KCP Management Ltd | Financial services | 2026 |
| KCR Investments Ltd | Real estate | 2024 |
| KCR Real Estate Ltd | Real estate | 2022 |
| KCT Holdings Limited | Professional & scientific | 1994 |
| KDB Book-Keeping Limited | Professional & scientific | 1996 |
| KDU Precision Engineering Ltd | Professional & scientific | 2016 |
| Keal Family Investments Ltd | Financial services | 2018 |
| Kean Consultancy Ltd | Professional & scientific | 2025 |
| Keedy Ltd | Real estate | 2022 |
| Keira Neve Aesthetics Ltd | Other services | 2023 |
| Keith Bennett Financial Services Ltd | Financial services | 2011 |
| Keith Cook Training Limited | Construction | 2009 |
| Kelfin Construction Ltd | Construction | 2025 |
| Kelfin Entertainment Ltd | Hospitality | 2026 |
| Kelly Baker Freelance & Consultancy Limited | Professional & scientific | 2021 |
| Kelside Ltd | Other services | 2019 |
| Kendrick & Sons Properties Ltd | Real estate | 2017 |
| Kensington Asset Management Limited | Financial services | 2007 |
| Kentas Limited | Transport & logistics | 2017 |
| Kentrate Limited | Wholesale & retail | 2016 |
| Kersian Trading Ltd | Wholesale & retail | 2026 |
| Kesel Construction (UK) Ltd | Construction | 2014 |
| Kestrel Close Management Company Limited | Households | 2022 |
| Kevin Bexley Limited | Professional & scientific | 2015 |
| Kevin Penhallurick Limited | Professional & scientific | 2016 |
| Key Performance Fitness Ltd | Arts & recreation | 2022 |
| Key Property Holdings Ltd | Real estate | 2019 |
| Keylink Auto Ltd | Wholesale & retail | 2024 |
| Keyquest Consultancy Limited | Professional & scientific | 2012 |
| Keystone Construction (Midlands) Limited | Construction | 2012 |
| Keystone Homes (Midlands) Limited | Construction | 2010 |
| Keyup Technology Limited | Information & communication | 2020 |
| KF Pizza House Limited | Hospitality | 2025 |
| Kfboo 2022 Limited | Hospitality | 2022 |
| Khan Care Ltd | Health & social care | 2017 |
| KHANS68 Ltd | Real estate | 2025 |
| Khazana Restaurant Limited | Hospitality | 2023 |
| KHL Smith Holdings Limited | Wholesale & retail | 2023 |
| Khrais Investments Ltd | Real estate | 2021 |
| Khumbu Consulting Ltd | Information & communication | 2015 |
| Kidney Nutrition Matters Ltd | Health & social care | 2026 |
| Kilo Wines Ltd | Wholesale & retail | 2016 |
| Kind Properties Ltd | Real estate | 2017 |
| Kinder Expeditions Limited | Education | 2026 |
| King COE Properties Ltd | Real estate | 2022 |
| Kingfisher Homes (Azure) Ltd | Real estate | 2024 |
| Kingfisher Music Publishing Limited | Information & communication | 2019 |
| Kings Couriers Limited | Transport & logistics | 2002 |
| Kings Pharmacy Ltd. | Wholesale & retail | 2023 |
| Kings Property Management & Lettings Ltd | Real estate | 2012 |
| Kings Residential Care Homes Limited | Health & social care | 2008 |
| Kingscliffe Day Nursery Limited | Extraterritorial | 1998 |
| Kingston Brook Inns Limited | Hospitality | 2015 |
| Kingswood Partnership Financial Planning Limited | Financial services | 2016 |
| Kingswood Trading and Investments Ltd | Construction | 2015 |
| Kinra Limited | Real estate | 2025 |
| Kinsbourne Holdings Limited | Financial services | 2016 |
| KIO Barber Ltd | Other services | 2025 |
| Kirby Fields Property Solutions Ltd | Real estate | 2022 |
| Kirby Muxloe Podiatry Ltd | Health & social care | 2016 |
| Kitchen & Bathroom Company Inc Limited | Construction | 2025 |
| Kitchen Spices Ltd | Hospitality | 2024 |
| Kite Catering Ltd | Hospitality | 2025 |
| Kitking Group Limited | Wholesale & retail | 2019 |
| Kitking Holdings Limited | Financial services | 2024 |
| Kitking Limited | Manufacturing | 2008 |
| Kitty Yoga London Ltd | Agriculture & fishing | 2024 |
| Kiwi Tents Ltd | Administrative & support | 2019 |
| Kixx Loughborough Limited | Arts & recreation | 2022 |
| Kjames Consultancy Limited | Wholesale & retail | 2019 |
| KJH Properties Limited | Real estate | 2004 |
| KJS Healthcare Limited | Health & social care | 2025 |
| KK Property Developments Ltd | Construction | 2018 |
| KK5 Ltd | Wholesale & retail | 2026 |
| KKP Homeapartments Ltd | Real estate | 2019 |
| KKP Property Investments Limited | Real estate | 2018 |
| KL Asset Management Ltd | Real estate | 2022 |
| KL Sewing Machines Limited | Manufacturing | 2012 |
| KLJ Services Limited | Administrative & support | 2017 |