| Kamali Optical Limited | Health & social care | 2012 |
| Kamar Foods Ltd | Wholesale & retail | 2019 |
| Kamelot Consulting Limited | Information & communication | 2014 |
| Kandy Healthcare Ltd | Health & social care | 2021 |
| Kangcheng UK Limited | Hospitality | 2019 |
| Kapital Investments Limited | Real estate | 2019 |
| Kapital RE Limited | Real estate | 2024 |
| Kapok Technologies Limited | Information & communication | 2013 |
| Kapook Ngein Ltd | Hospitality | 2022 |
| Kapow Primary Limited | Education | 2015 |
| Karai Estates Ltd | Real estate | 2018 |
| Karedent Limited | Health & social care | 1988 |
| Karian Limited | Real estate | 2025 |
| Karim Vehicles Limited | Wholesale & retail | 2018 |
| Karl Goodwin Consulting Ltd | Professional & scientific | 2020 |
| Karl Wood Heating Limited | Construction | 2016 |
| Karmichael Ltd. | Real estate | 2013 |
| Karsons Investments (UK) Limited | Real estate | 2017 |
| Karssk Ltd | Professional & scientific | 2025 |
| Karu Collective Limited | Transport & logistics | 2016 |
| Kasa Consulting Ltd | Financial services | 2025 |
| Kash Holdings Limited | Extraterritorial | 2019 |
| Kashmir 1 Limited | Hospitality | 2025 |
| Kasibor Ltd | Information & communication | 2021 |
| Kasutocare Limited | Administrative & support | 2021 |
| KAT Jameson Public Relations Limited | Professional & scientific | 2021 |
| Kate and Tom's Limited | Administrative & support | 2012 |
| Kate Gregory Ltd | Extraterritorial | 2015 |
| Kate Hall Arts Limited | Health & social care | 2016 |
| Kate Hunter Ltd | Health & social care | 2019 |
| Kate John Associates Limited | Administrative & support | 2015 |
| Katecares.Consultancy Limited | Real estate | 2023 |
| Katena Products UK Limited | Professional & scientific | 2018 |
| Katharina Hoerath Ltd | Professional & scientific | 2022 |
| Kati Creative Ltd | Manufacturing | 2026 |
| Katie Foster Physio Limited | Health & social care | 2014 |
| Katouch Limited | Health & social care | 2025 |
| Katron Engineering Precision Limited | Manufacturing | 1985 |
| Kaur Capital Limited | Financial services | 2015 |
| Kavcan Limited | Professional & scientific | 2023 |
| Kavicoltd Limited | Financial services | 2022 |
| KAY Associates Limited | Professional & scientific | 2023 |
| Kaze Digital & Data Limited | Professional & scientific | 2016 |
| Kaze Holdings Limited | Financial services | 2023 |
| KB Building Services UK Limited | Construction | 2007 |
| KB Distribution Ltd | Transport & logistics | 2015 |
| KB Independent Trustees Limited | Financial services | 2018 |
| Kbaj Group Limited | Professional & scientific | 2025 |
| KBG Ventures Limited | Administrative & support | 2025 |
| Kbrace.Sports Ltd | Wholesale & retail | 2024 |
| Kbvet Ltd | Professional & scientific | 2023 |
| KC Coaching Development Ltd | Education | 2024 |
| KC Elec Ltd | Construction | 2010 |
| Kcap Advisory Limited | Professional & scientific | 2024 |
| KCJ Training and Employment Solutions Ltd | Administrative & support | 2018 |
| KCP Owners Partnership Limited | Households | 2020 |
| KCR Developments Limited | Construction | 2025 |
| KCS Agri Limited | Agriculture & fishing | 2021 |
| Kctw Ltd | Real estate | 2017 |
| KD Consulting (Gloucester) Ltd | Wholesale & retail | 2011 |
| Kearsley Bess Limited | Energy | 2022 |
| Kebab U Like Limited | Hospitality | 2009 |
| Kedougou Gold Limited | Mining & quarrying | 2017 |
| Keepers Barns Limited | Real estate | 2016 |
| Keewave Ltd | Administrative & support | 2013 |
| Kei-Kei UK Ltd | Wholesale & retail | 2015 |
| Keith Prowse Training Limited | Education | 2011 |
| Keith Scarrott Shoes Limited | Wholesale & retail | 2000 |
| Keitone Building Ltd | Construction | 2013 |
| Kejomi Ltd | Information & communication | 2012 |
| Kelchopeg Limited | Transport & logistics | 2025 |
| Kellands Financial Planning (Cheltenham) Limited | Extraterritorial | 2022 |
| Kelmscott Consulting Limited | Professional & scientific | 2008 |
| Keman Limited | Other services | 2023 |
| Kembleton Ltd | Professional & scientific | 2024 |
| Kempton Park Holding Company Limited | Professional & scientific | 1877 |
| Kempton Park Racecourse Company Limited(The) | Professional & scientific | 1967 |
| Kempton Racecourse Investments Limited | Professional & scientific | 1969 |
| Kemsley Construction Ltd | Construction | 2015 |
| KEN Joynes & SON Ltd | Arts & recreation | 2004 |
| KEN Pink Plant Hire Ltd | Administrative & support | 2008 |
| Kenelm Property Ltd | Professional & scientific | 2023 |
| Kenilworth Square Ltd | Real estate | 2024 |
| Kennack Management Limited | Administrative & support | 2003 |
| Kennedy Asset Management Ltd | Real estate | 2026 |
| Kennedy Private Client Services (UK) Limited | Professional & scientific | 2018 |
| Kentish Communications Ltd | Other services | 2017 |
| Kenyon Davies Limited | Professional & scientific | 2016 |
| Kerep Limited | Real estate | 2021 |
| Kerr Darnley Limited | Professional & scientific | 2013 |
| Kesego Investment Ltd | Wholesale & retail | 2022 |
| Kess-Env Limited | Professional & scientific | 2019 |
| Kestrel Care Village Ltd | Administrative & support | 2017 |
| Kestrel Dental Studio Ltd | Health & social care | 2010 |
| Kestrel Investment Properties Limited | Real estate | 2017 |
| Kestrel Living Limited | Real estate | 2025 |
| Kettlewell House and Operations Limited | Health & social care | 2017 |
| Kevbill Travel Consult Ltd | Administrative & support | 2026 |
| Key Consulting Group Ltd | Professional & scientific | 2018 |
| Key Intelligence Ltd | Information & communication | 2004 |