| Klive Limited | Information & communication | 2016 |
| KMC Surveying Limited | Professional & scientific | 2018 |
| KMK International Limited | Professional & scientific | 2015 |
| Kmotos Ltd | Wholesale & retail | 2022 |
| Knight & Company Ltd | Professional & scientific | 2012 |
| Knights Building Services Limited | Construction | 2004 |
| Knights Mann Ltd | Wholesale & retail | 2019 |
| Knoll UK Investments Unlimited | Manufacturing | 2004 |
| Knowing Retail Limited | Construction | 2013 |
| Knowledge Limited | Extraterritorial | 1981 |
| Knowledgescape Ltd | Professional & scientific | 2012 |
| Knowsley Close Limited | Real estate | 2009 |
| Knutz Limited | Professional & scientific | 1979 |
| KOBE88 Limited | Financial services | 2022 |
| Kodam Accountants Ltd | Professional & scientific | 2021 |
| Kojima Productions UK Ltd | Information & communication | 2021 |
| Koju Retail Limited | Wholesale & retail | 2025 |
| Komen Ltd | Real estate | 1988 |
| Konig Technologies Limited | Information & communication | 2012 |
| Konnected Technology Ltd | Information & communication | 2022 |
| Kontax Engineering Limited | Manufacturing | 1964 |
| Konuri Limited | Real estate | 2022 |
| Kookoo Wellness Ltd. | Health & social care | 2022 |
| Koon AL Yamamah Ltd | Wholesale & retail | 2025 |
| Kori Development Project Ltd | Education | 2014 |
| Koysuren Holding Ltd | Financial services | 2026 |
| Kozlar Limited | Real estate | 2021 |
| Kozmeta Limited | Wholesale & retail | 2024 |
| KR Elixir Technology Limited | Information & communication | 2017 |
| KRA Maintenance Services Ltd | Manufacturing | 2023 |
| KRC International Projects Ltd | Financial services | 2019 |
| KRF Wholesale Ltd | Wholesale & retail | 2026 |
| Kriya Lettings Limited | Real estate | 2022 |
| Kriya Tech Limited | Information & communication | 2013 |
| Krotz Ltd | Wholesale & retail | 2024 |
| KRS Software Solutions Limited | Information & communication | 2014 |
| Krsmaharjan Ltd | Health & social care | 2023 |
| Krydafit Ltd | Information & communication | 2020 |
| Kshara Ltd | Transport & logistics | 2026 |
| Ksix Solutions Limited | Administrative & support | 2014 |
| KSP Superstore Limited | Wholesale & retail | 2015 |
| Kubatsira Ltd | Information & communication | 2025 |
| Kubbe Limited | Wholesale & retail | 2022 |
| Kuda Creative Ltd. | Information & communication | 2017 |
| Kudu Client Services Ltd | Professional & scientific | 2015 |
| Kudu Services LLP | | 2016 |
| Kultranova Limited | Wholesale & retail | 2026 |
| Kumulus International Holdings Limited | Professional & scientific | 2024 |
| Kumwenda Consulting Limited | Extraterritorial | 2015 |
| Kupi Limited | Health & social care | 2015 |
| Kuwa Ltd | Professional & scientific | 2018 |
| KV Property Ltd | Real estate | 2017 |
| KVS Design Associates Ltd | Professional & scientific | 2019 |
| KW & PV Crossley LLP | | 2017 |
| KW Accident Repairs Ltd. | Wholesale & retail | 2015 |
| KW Music Ltd | Arts & recreation | 2021 |
| Kybele Consultants Limited | Manufacturing | 2025 |
| Kyha Studios UK Limited | Wholesale & retail | 2025 |
| Kyle & Irving Limited | Professional & scientific | 2009 |
| Køhai Global Ltd | Information & communication | 2025 |
| L & D Printing Company Limited | Information & communication | 1984 |
| L a Collina (Maidenhead) Limited | Hospitality | 2014 |
| L a Doyle Limited | Administrative & support | 2017 |
| L Capital Advisory Ltd | Professional & scientific | 2019 |
| L Godfrey Services Ltd | Construction | 2021 |
| L P D Bayley Limited | Construction | 2015 |
| L R Garden Maintenance Ltd | Administrative & support | 2011 |
| L&R Care Ltd | Health & social care | 2025 |
| L.B.(Stewartby)Limited | Financial services | 1900 |
| L.E.S. Productions Ltd | Arts & recreation | 2024 |
| L.L. Potter & Sons (Taplow) Limited | Manufacturing | 1964 |
| LA Bergerie (France) Limited | Real estate | 1979 |
| LA Berkshire Limited | Wholesale & retail | 2007 |
| LA Dolfina Limited | Arts & recreation | 2021 |
| LA Tahjan Ltd | Hospitality | 2022 |
| LA Vanguardia Polo Team Limited | Arts & recreation | 2026 |
| Laavadar Ltd | Information & communication | 2025 |
| Labrad Investments Ltd | Real estate | 2019 |
| Laburnum Court Residents Association Limited | Households | 1970 |
| Lacey Enterprises Ltd | Administrative & support | 2018 |
| Ladfox Ltd | Manufacturing | 2026 |
| Lady Astor Management Limited | Households | 1996 |
| Ladybird Writer Ltd | Arts & recreation | 2025 |
| Lake House Cafe Limited | Hospitality | 2016 |
| Lakelands Construction Limited | Construction | 2011 |
| Lancaster Pads Limited | Real estate | 2017 |
| Lancing Ltd | Wholesale & retail | 2020 |
| Lancoux Ltd | Wholesale & retail | 2009 |
| Landid Asset Management 1 Limited | Real estate | 2018 |
| Landid Holdco Limited | Real estate | 2015 |
| Landid Living Limited | Real estate | 2025 |
| Landid Property Holdings Limited | Real estate | 2007 |
| Landid Putney Developments Limited | Real estate | 2016 |
| Landid Sunderland Developments Limited | Real estate | 2019 |
| Landid Tower Bridge Developments Limited | Real estate | 2018 |
| Landid TVP Limited | Real estate | 2019 |
| Landid Victoria Developments Limited | Real estate | 2022 |
| Landmark Estate Agents Limited | Real estate | 2024 |
| Landmark Trading Shottesbrooke Limited | Real estate | 1999 |
| Landscape Services (Maidenhead) Ltd | Administrative & support | 2007 |