| Keystone Accounting Ltd | Professional & scientific | 2023 |
| Keystone Cars Limited | Wholesale & retail | 2012 |
| Keystone Project Management Limited | Professional & scientific | 2022 |
| KHW Engineering Services Limited | Professional & scientific | 2017 |
| Kidby Properties Ltd | Real estate | 2026 |
| Kidderminster Crossley Specsavers Limited | Wholesale & retail | 2018 |
| Kidderminster Specsavers Hearcare Limited | Wholesale & retail | 2007 |
| Kidlington Specsavers Hearcare Limited | Wholesale & retail | 2024 |
| Kidlington Specsavers Limited | Wholesale & retail | 2018 |
| Kidz Inc Limited | Health & social care | 2002 |
| Kierda Construction Ltd | Construction | 2025 |
| Kihaiaprints Ltd | Manufacturing | 2023 |
| Kilburn Specsavers Hearcare Limited | Wholesale & retail | 2019 |
| Kilburn Specsavers Limited | Wholesale & retail | 1998 |
| Kilbyco Limited | Financial services | 2023 |
| Killingworth Specsavers Limited | Wholesale & retail | 2016 |
| Kilmarnock Specsavers Limited | Wholesale & retail | 1995 |
| Kilmarnock Visionplus Limited | Wholesale & retail | 1995 |
| Kiln Lane Specsavers Limited | Wholesale & retail | 2018 |
| Kilpeck Productions Ltd | Information & communication | 2012 |
| Kimberlin Limited | Financial services | 2024 |
| Kimiko Group Limited | Financial services | 2022 |
| Kineticmesh Limited | Arts & recreation | 2009 |
| King and Power Limited | Financial services | 2020 |
| Kingers Limited | Wholesale & retail | 2009 |
| Kingfisher Consulting and Strategy Limited | Professional & scientific | 2025 |
| Kingfisher Ridge Livery Ltd | Agriculture & fishing | 2025 |
| Kingfishers Ridge Limited | Other services | 2007 |
| Kings Lynn Domi Audiology Specsavers Limited | Wholesale & retail | 2025 |
| Kings Lynn Domiciliary Specsavers Limited | Wholesale & retail | 2018 |
| Kings Lynn Specsavers Hearcare Limited | Wholesale & retail | 2007 |
| Kings Lynn Specsavers Limited | Wholesale & retail | 1992 |
| Kings Lynn Visionplus Limited | Wholesale & retail | 1992 |
| Kingsbridge Creek Ltd | Wholesale & retail | 2021 |
| Kingsbury Specsavers Limited | Wholesale & retail | 2011 |
| Kingsfield Management Ltd | Wholesale & retail | 1996 |
| Kingsgate Education Ltd | Education | 2025 |
| Kingsgate School Ltd | Education | 2017 |
| Kingsheath Specsavers Limited | Wholesale & retail | 1995 |
| Kingsheath Visionplus Limited | Wholesale & retail | 1995 |
| Kingshill Limited | Professional & scientific | 2000 |
| Kingsley Property Rental Ltd | Real estate | 2020 |
| Kingston Court (Maybush) Management Company Limited | Households | 1988 |
| Kingston Electrical Solutions Limited | Construction | 2022 |
| Kingston Farmhouse Limited | Real estate | 2005 |
| Kingston-Upon-Thames Specsavers Hearcare Limited | Wholesale & retail | 2006 |
| Kingswell Design & Build Services Limited | Construction | 2017 |
| Kingswell Kitchens and Bedrooms Limited | Construction | 2015 |
| Kingswinford Specsavers Limited | Wholesale & retail | 2017 |
| Kingswood Place (Knowle) Management Company Limited | Households | 2003 |
| Kingswood Specsavers Limited | Wholesale & retail | 1995 |
| Kingswood Visionplus Limited | Wholesale & retail | 1995 |
| Kingwilliam Visionplus Limited | Wholesale & retail | 1999 |
| Kiniken Dynamics Ltd | Wholesale & retail | 2025 |
| Kinima Collective Limited | Professional & scientific | 2025 |
| Kirby Safety Solutions Ltd | Professional & scientific | 2026 |
| Kirkby Specsavers Limited | Wholesale & retail | 2005 |
| Kirkby Trampoline Club Limited | Education | 2024 |
| Kirkby Visionplus Limited | Wholesale & retail | 2005 |
| Kirkcaldy Specsavers Limited | Wholesale & retail | 1998 |
| Kirkintilloch Specsavers Limited | Wholesale & retail | 2007 |
| Kirkintilloch Visionplus Limited | Wholesale & retail | 2007 |
| Kirkstall Specsavers Hearcare Limited | Wholesale & retail | 2018 |
| Kirkstall Specsavers Limited | Wholesale & retail | 2000 |
| Kisibo Mugera Limited | Professional & scientific | 2026 |
| Kiss Cars Limited | Wholesale & retail | 2019 |
| Kissing Gate Events Ltd | Hospitality | 2017 |
| Kissing Kippers Limited | Manufacturing | 2015 |
| Kisstech Ltd | Wholesale & retail | 2018 |
| Kitchen Luxe Limited | Construction | 2008 |
| Kiwy Property Limited | Real estate | 2026 |
| KJC Drainage Limited | Water & waste | 2022 |
| Kjissnnsam Limited | Wholesale & retail | 2025 |
| KJS Plant Hire and Haulage Ltd | Construction | 2015 |
| KJW Construction Ltd | Construction | 2026 |
| Kkav Limited | Manufacturing | 2016 |
| KL Productions Ltd | Information & communication | 2026 |
| Klas Groundworks Ltd | Construction | 2011 |
| Klean & Kind Cleaning Services Ltd | Administrative & support | 2023 |
| KLM Envision Ltd | Information & communication | 2026 |
| Klym&Co. Ltd | Information & communication | 2019 |
| Klystron Limited | Construction | 1988 |
| KMB Home Storage Ltd | Transport & logistics | 2024 |
| KMJ Group Limited | Financial services | 2017 |
| KMS Waste Services Limited | Construction | 2019 |
| KND Plastering Ltd | Construction | 2023 |
| Knight Architectural Design Limited | Construction | 2012 |
| Knight Shaw Ltd | Financial services | 2019 |
| KNM Catering Limited | Hospitality | 2024 |
| Knock OUT Embroidery Ltd | Manufacturing | 2021 |
| Knotweed Specialists UK Limited | Other services | 2018 |
| Knowle Cars Limited | Wholesale & retail | 2018 |
| Knowle Gutters and Fascia Specialists Ltd | Construction | 2025 |
| Knowle Specsavers Limited | Wholesale & retail | 2002 |
| Knowles EOD & Maritime Services Ltd | Professional & scientific | 2019 |
| Knowles-Wilkins Engineering (KWE) Limited | Wholesale & retail | 2002 |
| Knowlton-Jones Ltd | Professional & scientific | 2016 |
| Knox Properties Ltd | Real estate | 2024 |
| Kokoyemi Logistics Ltd | Transport & logistics | 2025 |
| Koloex Ltd | Wholesale & retail | 2022 |