| Kilbarron Properties Limited | Real estate | 2019 |
| Kilnacre Limited | Administrative & support | 2004 |
| Kilo Oscar Charlie Alpha Juliet Ltd | Professional & scientific | 2023 |
| Kilpeacon House Management Ltd | Households | 2019 |
| Kilroy Estate Agents Limited | Professional & scientific | 1993 |
| KIM Marlor Associates Limited | Professional & scientific | 2008 |
| Kimakem UK Ltd | Wholesale & retail | 2026 |
| Kimber Harries Consulting Ltd | Professional & scientific | 2021 |
| Kimere Building Company Limited | Real estate | 1946 |
| Kinder Genius Limited | Education | 2024 |
| Kindness Kahuna Naiads Ltd | Health & social care | 2023 |
| Kindredpeople Ltd | Professional & scientific | 2025 |
| Kindy Consultancy Limited | Professional & scientific | 2025 |
| Kinectrics UK Limited | Professional & scientific | 2006 |
| King & Chasemore Limited | Extraterritorial | 1994 |
| King Street Estates Limited | Real estate | 2003 |
| King Street Investments Limited | Hospitality | 2012 |
| Kings Gate (Macclesfield) Management Company Limited | Households | 2024 |
| Kings Gate Developments Limited | Construction | 2003 |
| Kings Waterfront (Estates) Limited | Real estate | 2005 |
| Kingsbrook Court Management Company Limited | Households | 1980 |
| Kingsleigh Properties Limited | Real estate | 2024 |
| Kingsnorth Business Solutions Limited | Administrative & support | 2014 |
| Kingston Brook Ltd | Administrative & support | 2023 |
| Kingsway Apartments Altrincham Management Company Limited | Households | 2003 |
| Kingswood (Ashton-Under-Lyne) Management Company Limited | Households | 2004 |
| Kingwright LLP | | 2018 |
| Kinloch Controls Limited | Professional & scientific | 2021 |
| KIO Architecture and Design Ltd | Professional & scientific | 2021 |
| Kiran Upstream Global Solutions Limited | Administrative & support | 2013 |
| Kiran’S Hair & Beauty Ltd | Other services | 2022 |
| Kirdico Ltd | Real estate | 2018 |
| Kirkburton Computing Limited | Professional & scientific | 2020 |
| Kirklee (Bowdon) Management Company Limited | Households | 1988 |
| Kirklees Dental Centre Ltd | Health & social care | 2024 |
| Kirkley Property Ltd | Real estate | 2020 |
| Kirkmain Professionals Ltd | Health & social care | 2022 |
| Kirkman Architects Limited | Professional & scientific | 2005 |
| Kirn Estates Limited | Other services | 2018 |
| Kishawi Limited | Real estate | 2009 |
| Kishfield Group Limited | Administrative & support | 2017 |
| Kitch Technologies Ltd | Hospitality | 2019 |
| Kitson Architecture Limited | Professional & scientific | 2012 |
| Kitson Keegan Utility Services Limited | Construction | 2006 |
| Kiwinium Limited | Professional & scientific | 2023 |
| Kizerigs Limited | Construction | 2019 |
| KJM Construction Solutions Limited | Professional & scientific | 2012 |
| KK Taylor Ltd | Information & communication | 2015 |
| Kkmj Limited | Financial services | 2026 |
| Klarius Products Ltd | Manufacturing | 2012 |
| Klaud AI Ltd | Information & communication | 2026 |
| Klayform Solutions Ltd | Professional & scientific | 2021 |
| KLB Catering Limited | Hospitality | 2016 |
| KLB Leisure Ltd | Other services | 2024 |
| KLC Marketing Ltd | Professional & scientific | 2019 |
| Klear AI Holding Limited | Financial services | 2025 |
| Klein Accountancy Limited | Professional & scientific | 2016 |
| Kleine Opera Ltd | Arts & recreation | 2026 |
| Klevaland Limited | Information & communication | 2021 |
| KLM Beauty Ltd | Other services | 2018 |
| Klosr Design Ltd | Professional & scientific | 2022 |
| Klosr Pools Ltd | Construction | 2022 |
| Klsc Ltd | Financial services | 2025 |
| KLT Agencies Ltd | Administrative & support | 2008 |
| Klytech Dynamics Limited | Professional & scientific | 2025 |
| KM Adams Limited | Professional & scientific | 2021 |
| KM Sport Psychology Ltd | Other services | 2019 |
| KM Tools Limited | Manufacturing | 2012 |
| KMC Investments Ltd | Real estate | 2019 |
| Kmpi Ltd | Information & communication | 2019 |
| KMR Family Investments Ltd | Professional & scientific | 2018 |
| Knapcap Ltd | Financial services | 2024 |
| Knct Limited | Construction | 2025 |
| Knightsbridge Real Estate Properties Ltd | Real estate | 2025 |
| Knightsbridge Residences Ltd | Real estate | 2020 |
| Knightsbridge Retail Partners Limited | | 2007 |
| Knnak Limited | Real estate | 2016 |
| Knock & Talk Infra Ltd | Real estate | 2021 |
| Knoll (Dunham) Management Company Limited(The) | Households | 1975 |
| Knowledge Boost Ltd | Information & communication | 2020 |
| Knowledge Engine Solutions Limited | Professional & scientific | 2023 |
| Knowledge Gaps Limited | Professional & scientific | 2004 |
| Knowledgemotion (Boclips) Ltd | Information & communication | 2025 |
| Knowles Squared Limited | Real estate | 2024 |
| Knst Ltd | Health & social care | 2025 |
| Kobbysoft Limited | Administrative & support | 2015 |
| Kokanawala Limited | Professional & scientific | 2021 |
| Koko Bay Ltd | Wholesale & retail | 2018 |
| Komor Transport Ltd | Transport & logistics | 2024 |
| Kooli Ltd | Wholesale & retail | 2023 |
| Koppenberg Limited | Professional & scientific | 2022 |
| KOR Events Limited | Arts & recreation | 2023 |
| KOR Life Limited | Arts & recreation | 2024 |
| Kork Properties Limited | Real estate | 2022 |
| Kornelle Limited | Professional & scientific | 2025 |
| Korrison Engineering Limited | Professional & scientific | 2022 |
| Kosmos Consulting Limited | Professional & scientific | 2025 |
| Kosttop Ltd | Professional & scientific | 2023 |
| Koto Holdings Ltd | Real estate | 2023 |
| Koukouvayia Insights and Marketing Ltd | Professional & scientific | 2024 |