| Kitchen Sinking Limited | Hospitality | 2026 |
| Kitchens Direct Limited | Extraterritorial | 2011 |
| Kitching Plant Hire Ltd | Administrative & support | 2011 |
| Kitson Couriers Ltd | Transport & logistics | 2025 |
| KJE Consultancy Limited | Professional & scientific | 2017 |
| Kjh-Uk Ltd | Professional & scientific | 2011 |
| KJK Trading Ltd | Wholesale & retail | 2024 |
| Kl&Jp Adams Ltd | Health & social care | 2018 |
| Klein Consulting Ltd | Professional & scientific | 2025 |
| Klimax Limited | Wholesale & retail | 2021 |
| Kliniken Consulting Limited | Professional & scientific | 2025 |
| Kliniken Limited | Manufacturing | 2020 |
| Klippsafe Limited | Professional & scientific | 2007 |
| Klipspringer Property Investments Limited | Real estate | 2013 |
| KME Investments (UK) Limited | Administrative & support | 2004 |
| KMK Property Solutions Limited | Real estate | 2024 |
| Knaresborough Associates Limited | Real estate | 1997 |
| Knaresborough Building & Joinery Ltd | Construction | 2024 |
| Knaresborough Fabrications Limited | Manufacturing | 2024 |
| Knaresborough Motor Company Ltd | Wholesale & retail | 2024 |
| Knaresborough NOW LLP | | 2014 |
| Knaresborough Properties Ltd | Real estate | 2000 |
| Knaresborough Property Co. Limited | Real estate | 1962 |
| Knaresborough Tyre & Autocare Limited | Wholesale & retail | 2013 |
| Knaresborough Tyre Services Limited | Wholesale & retail | 2002 |
| Knet Ltd | Information & communication | 2017 |
| Knight Richardson Limited | Professional & scientific | 2019 |
| Knightbury Limited | Construction | 2025 |
| Knights Roofing Limited | Construction | 2017 |
| Knokus Limited | Hospitality | 2025 |
| Knottinger Limited | Wholesale & retail | 2025 |
| Knox Mechanical and Electrical Ltd | Construction | 2023 |
| Knox Sawmills Limited | Construction | 2007 |
| Knoxville Limited | Extraterritorial | 2026 |
| Kobb Interiors Ltd | Construction | 2020 |
| Koch Limited | Extraterritorial | 2022 |
| Koliba Consulting Ltd | Professional & scientific | 2021 |
| Kolina Limited | Water & waste | 2008 |
| Konak Meze Ltd | Hospitality | 2013 |
| Konoz Aljana Ltd | Wholesale & retail | 2023 |
| Koo-Ki Limited | Wholesale & retail | 2024 |
| Kookaburra Associates Limited | Information & communication | 2010 |
| Koparo Limited | Professional & scientific | 2010 |
| Koray GUL Consultancies Limited | Professional & scientific | 2018 |
| Korb Joinery Ltd | Manufacturing | 2026 |
| Kore Wireless UK Limited | Administrative & support | 2003 |
| Kotonya Ltd | Health & social care | 2025 |
| Kpjms Limited | Other services | 2006 |
| Kpoulter Ltd | Transport & logistics | 2025 |
| KR Harrogate Limited | Hospitality | 2017 |
| KR Motors Ltd | Wholesale & retail | 2012 |
| Kreative Embroidery & Design Limited | Wholesale & retail | 2021 |
| Kris Stephenson Builders Limited | Construction | 2017 |
| Krisalyn Limited | Administrative & support | 2019 |
| Kristi Ltd | Extraterritorial | 2013 |
| Kristian Matthew Ltd | Wholesale & retail | 2025 |
| Krysallis Ltd | Health & social care | 2024 |
| KS Composites Production Limited | Manufacturing | 2016 |
| Ksbo 2016 | Professional & scientific | 2016 |
| KSC LE14 Limited | Professional & scientific | 2025 |
| KSF Acquisition UK Limited | Professional & scientific | 2014 |
| KSJ Etrade Ltd | Wholesale & retail | 2025 |
| KSJ Group Ltd | Financial services | 2024 |
| KSR Property Partners Ltd | Real estate | 2024 |
| KSS Trustees Limited | Administrative & support | 2024 |
| KT Business Services Limited | Professional & scientific | 2010 |
| KTA TKD Ltd | Other services | 2019 |
| KTB Property Investments Limited | Households | 2022 |
| Kube Sound Isolation Ltd | Construction | 2017 |
| Kudu Coaching Limited | Administrative & support | 2024 |
| Kudu Space Limited | Real estate | 2021 |
| Kulahub Limited | Information & communication | 2010 |
| Kurdishh Style Barber Ltd | Other services | 2021 |
| Kuredu Consultants Ltd | Professional & scientific | 2026 |
| Kuriso Solutions Ltd | Information & communication | 2017 |
| Kurtis Limited | Extraterritorial | 2026 |
| KUS Designs Ltd | Professional & scientific | 2025 |
| KVE Digital Services Ltd | Professional & scientific | 2024 |
| KW2022 Ltd | Real estate | 2022 |
| KXR Group Ltd | Information & communication | 2025 |
| Kyorke.Codes Ltd | Information & communication | 2024 |
| Kyte Pro Ltd | Information & communication | 2024 |
| KZ Fusion Ltd | Hospitality | 2025 |
| L & GL Osguthorpe Builders Limited | Construction | 2026 |
| L Cantwell Consulting 2 Limited | Professional & scientific | 2017 |
| L Cantwell Consulting Limited | Professional & scientific | 2017 |
| L Delaney Company Ltd | Real estate | 2025 |
| L G Couriers Limited | Transport & logistics | 2010 |
| L G Properties Leeds Limited | Real estate | 2017 |
| L Gawthorpe Marketing Services Limited | Professional & scientific | 2012 |
| L R V Creative Limited | Information & communication | 2018 |
| L W Ashby Limited | Construction | 2002 |
| L&M Arte Limited | Arts & recreation | 2026 |
| L. P. Balmforth & SON Limited | Wholesale & retail | 1976 |
| L1AM Limited | Extraterritorial | 2018 |
| L1LLY Limited | Extraterritorial | 2020 |
| L1NDA Limited | Extraterritorial | 2020 |
| L1NDON Ltd | Extraterritorial | 2020 |
| L1ONEL Limited | Extraterritorial | 2020 |
| L1QUOR Ltd | Extraterritorial | 2020 |