| Keenclick Ltd | Information & communication | 2021 |
| Keep IT Green Winchester Ltd | Administrative & support | 2024 |
| Keeping IT Human Ltd | Professional & scientific | 2015 |
| Keetons Hill Car Park Ltd | Transport & logistics | 2020 |
| Keetons Holdings Limited | Financial services | 2006 |
| Keetons Management Services Limited | Professional & scientific | 1938 |
| Keith Evans Architects Ltd | Professional & scientific | 2019 |
| Keith Sammons Ltd | Education | 2015 |
| Kelly and Lake Construction Limited | Construction | 2024 |
| Kent HAY & Straw Ltd | Agriculture & fishing | 2020 |
| Kenvention Limited | Financial services | 2023 |
| Kepco Limited | Real estate | 1982 |
| Kernow Dinas Ltd | Real estate | 2017 |
| Kerrfield Freeholders Ltd | Extraterritorial | 2011 |
| Kerrie Lacey Swimming Limited | Education | 2018 |
| Kesby and Company Ltd | Professional & scientific | 2008 |
| Kessel Development Ltd | Construction | 2019 |
| Keyhaven Homes Limited | Real estate | 2003 |
| Keyhaven Homes Skipton Ltd | Real estate | 2003 |
| Keylink Southern Auto Services Limited | Wholesale & retail | 2005 |
| Keystone Land Partners Ltd | Real estate | 2026 |
| Keystone Property Company Limited | Real estate | 1994 |
| Keystone Property Portfolio Ltd | Real estate | 2026 |
| Kg&S Ltd | Professional & scientific | 2006 |
| KGM Capital Limited | Information & communication | 2022 |
| Kichi Studio Ltd | Wholesale & retail | 2021 |
| Kid-A Ltd | Wholesale & retail | 2019 |
| Kidz OUT and About Ltd | Information & communication | 2019 |
| Kielder Consulting Limited | Professional & scientific | 2024 |
| Kieser Property Holdings Limited | Financial services | 2021 |
| Kikhaun Ltd | Administrative & support | 2009 |
| Kildare Associates Ltd | Construction | 2024 |
| Kilgour & Co Limited | Other services | 2006 |
| Killerton Storage Limited | Administrative & support | 2021 |
| Kilobyte Ltd | Extraterritorial | 2024 |
| Kimball Smith Consultants Limited | Professional & scientific | 2001 |
| Kimball Smith Limited | Professional & scientific | 1994 |
| Kimpton Manor Farm Limited | Agriculture & fishing | 2014 |
| Kindling Forest School CIC | Education | 2020 |
| Kinetic Letters Limited | Education | 2014 |
| King Alfred Motor Services Limited | Wholesale & retail | 2020 |
| King Architecture and Design Limited | Professional & scientific | 2020 |
| King William Court Management Co Limited | Real estate | 2017 |
| Kings Building & Maintenance Ltd | Construction | 2021 |
| Kings of Hampshire Ltd | Construction | 2020 |
| Kingsgate Hard Courts,Limited | Arts & recreation | 1932 |
| Kingsgate Lawn Tennis Club | Arts & recreation | 2020 |
| Kingsgate Mortgages Limited | Financial services | 2021 |
| Kingsgate Ridge Estates Ltd | Real estate | 2024 |
| Kingswell Buildings Ltd | Construction | 2018 |
| Kingswell Holdings Limited | Financial services | 2016 |
| Kingsworthy Foundry Company Limited | Wholesale & retail | 2016 |
| Kinnear and Company Limited | Professional & scientific | 2012 |
| Kipr Group Limited | Wholesale & retail | 2022 |
| Kirrin Ventures Limited | Hospitality | 2016 |
| Kirstie Green Limited | Education | 2014 |
| Kirtling Properties Limited | Real estate | 2002 |
| KIT and Kaboodle Ltd | Construction | 2005 |
| Kitani Chalmee Limited | Health & social care | 2019 |
| Kitchens of Winchester Ltd | Wholesale & retail | 2024 |
| Kite Projects Ltd | Wholesale & retail | 2022 |
| Kite Solutions Limited | Professional & scientific | 2010 |
| Kitelands HR Ltd | Administrative & support | 2022 |
| Kitemark Limited | Professional & scientific | 2017 |
| Kitemore Developments Limited | Construction | 2023 |
| KJ Halls Decorating Ltd | Construction | 2026 |
| KJ RIJ Limited | Education | 2023 |
| KLG SC Limited | Professional & scientific | 2013 |
| Klickstik Ltd | Information & communication | 2022 |
| Klik Consulting Limited | Hospitality | 2024 |
| KLP Climate Consulting Ltd | Professional & scientific | 2025 |
| KM MED Consultants Ltd | Health & social care | 2014 |
| KMO Marine Limited | Manufacturing | 2002 |
| Knion Ltd | Professional & scientific | 2019 |
| Knowledge-Based Management Consultants Limited | Professional & scientific | 2002 |
| Known Source Ltd | Wholesale & retail | 2020 |
| Koios Master Data Limited | Information & communication | 2017 |
| Komago Consulting Limited | Information & communication | 2025 |
| Komporgam Ltd. | Professional & scientific | 2015 |
| Konings Detailing Ltd | Other services | 2008 |
| Koylan Fashions Ltd | Wholesale & retail | 2023 |
| Koyn Limited | Information & communication | 2022 |
| KPD Properties Limited | Households | 2016 |
| Kpos Limited | Administrative & support | 2007 |
| KRG Associates Ltd | Professional & scientific | 2024 |
| Krispin Consulting Ltd | Information & communication | 2022 |
| Krmg Services Ltd | Professional & scientific | 2025 |
| KS Accountancy & Taxation Solutions Limited | Extraterritorial | 2008 |
| KS Alternative Ltd | Health & social care | 2015 |
| KS Eleven Digital Ltd | Administrative & support | 2020 |
| Ksail Events Ltd | Education | 2023 |
| Kudu Consultancy Ltd | Professional & scientific | 2015 |
| Kulpa Limited | Professional & scientific | 2019 |
| Kumalemon Communication Ltd | Professional & scientific | 2024 |
| Kurn & Kurn Ltd | Professional & scientific | 2013 |
| Kurn and Street Limited | Construction | 2021 |
| KW Investments Limited | Professional & scientific | 2008 |
| KWF Investments Co. Ltd | Real estate | 1945 |
| Kwgc Ltd | Information & communication | 2024 |
| Kydd Dental Limited | Health & social care | 2025 |