| Kennet Design Limited | Professional & scientific | 2010 |
| Kennet Media | Extraterritorial | 2020 |
| Kenneth Towle Limited | Professional & scientific | 2015 |
| Kennett Court Limited, | Households | 1963 |
| Kent Immigration and Visa Advice Limited | Professional & scientific | 2019 |
| Kentwood House Investments Limited | Real estate | 1969 |
| Kepler Communications UK Ltd | Information & communication | 2016 |
| Kept Assets Guidance Limited | Professional & scientific | 2025 |
| Kernahan Property Limited | Financial services | 2022 |
| Kernexis Ltd | Information & communication | 2025 |
| Kerry Inns Ltd | Hospitality | 2022 |
| Kesetian Limited | Professional & scientific | 2019 |
| Kestrel Advisors Limited | Administrative & support | 2017 |
| Keystone Coaching Ltd | Professional & scientific | 2019 |
| Keystone Copywriting Ltd | Professional & scientific | 2024 |
| KG Investments Newbury Ltd | Real estate | 2010 |
| KGB Construction Management Ltd | Professional & scientific | 2016 |
| Khanom Street Food Limited | Hospitality | 2025 |
| Khonkaen Thai Limited | Hospitality | 2017 |
| Kickery Ltd | Information & communication | 2023 |
| Kickfire Group Ltd. | Information & communication | 2019 |
| Kicktek Limited | Administrative & support | 2013 |
| Killybegs Solutions Limited | Information & communication | 2024 |
| Kilo Properties Limited | Construction | 2011 |
| Kimeze Enterprises Ltd | Manufacturing | 2018 |
| Kindness in Motion CIC | Wholesale & retail | 2025 |
| King Alfred Terrace Management Company Limited | Real estate | 2012 |
| Kingdom Knights Properties Ltd | Real estate | 2021 |
| Kings Interiors Ltd | Professional & scientific | 2021 |
| Kingsbrook (UK) Limited | Administrative & support | 2016 |
| Kingsclere Consulting Ltd | Professional & scientific | 2020 |
| Kingsclere PA College Limited | Education | 2024 |
| Kingsclere Performing Arts and Youth Centre CIC | Real estate | 2021 |
| Kingsclere Performing Arts College Ltd | Education | 2017 |
| Kingsclere Rugby Football Club Limited | Arts & recreation | 2010 |
| Kingsclere Vets Limited | Professional & scientific | 2021 |
| Kingsland House (Newbury) Limited | Households | 2004 |
| Kintbury Mill Management Company Limited | Households | 1982 |
| Kirkby Components Limited | Extraterritorial | 1975 |
| Kirkman Technologies Ltd | Manufacturing | 2019 |
| Kirsty Harris Physiotherapy Limited | Health & social care | 2014 |
| Kitchen Angels Ltd | Hospitality | 2013 |
| Kitchin Squared Ltd | Hospitality | 2024 |
| Kitenge Ltd | Manufacturing | 2014 |
| Kitplus Auctions Limited | Extraterritorial | 2026 |
| Kitplus Limited | Information & communication | 2005 |
| Kiwera Ltd | Health & social care | 2019 |
| Kiwi Bart Ltd | Information & communication | 2025 |
| KJ Telecom Solutions Limited | Construction | 2017 |
| Kjap Build & Design Limited | Professional & scientific | 2017 |
| KL Investment Property Advisors Limited | Real estate | 2022 |
| KM Concrete Cutting Services Limited | Construction | 2013 |
| KMT Food Ltd | Hospitality | 2021 |
| Knack Pictures Ltd | Information & communication | 2020 |
| Knight IT Group Ltd | Information & communication | 2014 |
| Knights Valley Hotels Limited | Professional & scientific | 1983 |
| Knights Valley Limited | Professional & scientific | 1983 |
| Knights Water Ltd | Manufacturing | 2026 |
| Knightsbridge 8 Limited | Real estate | 2017 |
| Know Mobile Ltd | Information & communication | 2025 |
| Knowhow Limited | Administrative & support | 2009 |
| Knowledgecast Limited | Extraterritorial | 2001 |
| Knowledgepoint Limited | Manufacturing | 1997 |
| KNS Digital Space Ltd | Wholesale & retail | 2026 |
| Koblola Consultancy Ltd | Other services | 2024 |
| Koci Houses Limited | Real estate | 2025 |
| Koko Place Ltd | Wholesale & retail | 2024 |
| Kolloidal Management Services Limited | Real estate | 2010 |
| Komos Solutions Ltd | Information & communication | 2014 |
| Kompetently Holdings Limited | Financial services | 2024 |
| Kompetently Ltd | Information & communication | 2024 |
| Kosnic Lighting Limited | Manufacturing | 2002 |
| Kostca Limited | Transport & logistics | 2014 |
| KPL Accounting Services Limited | Professional & scientific | 2024 |
| KRE Consulting Ltd | Other services | 2021 |
| Kremer Ireson Ltd | Administrative & support | 2017 |
| KRG Finance Services Ltd | Professional & scientific | 2022 |
| Krissy's Canines Ltd | Other services | 2022 |
| Krowpin Limited | Real estate | 2012 |
| KSC Marketing Ltd | Professional & scientific | 2014 |
| KT & DB Holdings Limited | Financial services | 2012 |
| KT PR Plus Limited | Health & social care | 2013 |
| KV Hotels Limited | Professional & scientific | 2005 |
| KW Proposal Services Ltd | Administrative & support | 2025 |
| Kwiksand Limited | Transport & logistics | 2003 |
| Kyffin PR Ltd | Wholesale & retail | 2014 |
| Kyle Seeley Associates Ltd | Professional & scientific | 2022 |
| Kynetec Bidco UK Ltd. | Financial services | 2021 |
| Kynetec Intermediate I UK Ltd. | Financial services | 2021 |
| Kynetec Intermediate II UK Ltd. | Financial services | 2021 |
| Kynetec UK Limited | Professional & scientific | 2001 |
| Kynetec UK Topco Ltd. | Financial services | 2021 |
| Kyte Marketing Solutions Limited | Administrative & support | 2000 |
| L & S Design Projects Limited | Construction | 2017 |
| L James Consulting Ltd | Information & communication | 2025 |
| L Schneider Sales Ltd | Wholesale & retail | 2025 |
| L8B Ltd | Information & communication | 2021 |
| LA Assist Ltd | Information & communication | 2025 |
| Ladybrand Limited | Information & communication | 1995 |
| Ladygrove Centre (Didcot) Management Limited | Real estate | 2003 |