| Kencon Ltd | Information & communication | 2021 |
| Kenetik Limited | Real estate | 2007 |
| Kenfan Industries Limited | Manufacturing | 2015 |
| Kenlowe Limited | Extraterritorial | 2015 |
| Kensons (Printing & Advertising Services) Limited | Manufacturing | 1971 |
| Kent Perfect Homes Limited | Real estate | 2021 |
| Kentmere Place Residents Association Limited | Extraterritorial | 2004 |
| Kentwone Dogs Limited | Other services | 2021 |
| Kenzie London Ltd | Wholesale & retail | 2025 |
| Kerry Foot Health Limited | Health & social care | 2024 |
| Kesgrave K Management Company Limited | Extraterritorial | 2005 |
| Ketpm Limited | Administrative & support | 2015 |
| Kettle Medical Services Ltd | Health & social care | 2023 |
| Kevantro Ltd | Wholesale & retail | 2026 |
| Kevin Pryce Garden Maintenance Limited | Administrative & support | 2007 |
| Kevin Sears Carpentry Limited | Construction | 2003 |
| KEW Place (High Wycombe) Management Company Limited | Households | 2003 |
| Kewferry Services Limited | Professional & scientific | 2008 |
| Key C Limited | Professional & scientific | 2017 |
| Key Homes Property Services Ltd | Real estate | 2017 |
| Key Passenger Logistic Solutions Ltd | Professional & scientific | 2021 |
| Keyan 2024 Ltd | Hospitality | 2024 |
| Keychange Consulting Limited | Administrative & support | 2026 |
| Keystone Build Solutions Ltd | Professional & scientific | 2025 |
| Kezlan Images Limited | Wholesale & retail | 2013 |
| KF Window Cleaning Ltd | Administrative & support | 2016 |
| KFA Estates Ltd | Real estate | 2026 |
| KFB Construction Ltd | Construction | 2016 |
| KG Metro Ltd | Wholesale & retail | 2024 |
| KGC Academy Ltd | Education | 2023 |
| Kgraabek Consulting Limited | Professional & scientific | 2017 |
| Khadiawala Limited | Real estate | 2023 |
| Khan's Catering Limited | Wholesale & retail | 2020 |
| KHAN381 Ltd | Construction | 2025 |
| Kharian Properties Limited | Real estate | 2025 |
| Khatana Foundation | Other services | 2022 |
| Khay Care Ltd | Health & social care | 2013 |
| Khazanaa Ltd | Wholesale & retail | 2025 |
| Khepera CIC | Health & social care | 2015 |
| Khidma Funeral Services Limited | Other services | 2021 |
| Khira Consulting Limited | Professional & scientific | 2019 |
| Khosla DOC Ltd | Health & social care | 2024 |
| Khumb Parcel Co Limited | Transport & logistics | 2025 |
| Khurana Brothers Ltd | Wholesale & retail | 2022 |
| Khurana's Superstore Limited | Wholesale & retail | 2024 |
| KIA Aileen Limited | Education | 2022 |
| Kiaf Limited | Construction | 2011 |
| Kicked Limited | Health & social care | 2025 |
| Kickstart London Community Interest Company | Professional & scientific | 2020 |
| Kiddy Cars Ltd | Administrative & support | 2018 |
| Kiddy International Ltd | Professional & scientific | 1993 |
| Kidspire Ltd | Health & social care | 2019 |
| Kiesh Limited | Wholesale & retail | 2019 |
| Kilimanjaro Limited | Professional & scientific | 1999 |
| Killer Dynamics Ltd | Information & communication | 2024 |
| Kilowatts Electrics Ltd | Construction | 2021 |
| KIM Turner Properties Limited | Real estate | 2025 |
| Kimbletech Ltd | Construction | 2011 |
| KIN Ventures Ltd | Administrative & support | 2019 |
| Kinara Training Limited | Education | 2024 |
| Kindness in Bucks CIC | Health & social care | 2025 |
| Kinesis Wellness Ltd | Hospitality | 2024 |
| Kinetic Notion Limited | Professional & scientific | 2013 |
| Kineticore Consultant Ltd | Professional & scientific | 2025 |
| Kinetik Consulting Ltd | Information & communication | 2010 |
| King Decorating Ltd | Construction | 2017 |
| King Installations Limited | Construction | 2014 |
| King Street Cloisters Management Limited | Real estate | 1991 |
| Kingdom Heating Services Ltd | Construction | 2021 |
| Kingdom Investments & Asset Management Ltd | Real estate | 2019 |
| Kingfisher Property Investments Ltd | Real estate | 1987 |
| Kings Education Trust | Education | 2017 |
| Kingshill Autos Ltd | Wholesale & retail | 2023 |
| Kingshill Property Investments Ltd | Real estate | 2024 |
| Kingshills Estate Agents (Franchises) Ltd | Real estate | 2021 |
| Kingshills Estate Agents (Lettings) Ltd | Real estate | 2020 |
| Kingshills Estate Agents Ltd | Real estate | 2019 |
| Kingside Properties Ltd | Administrative & support | 2024 |
| Kingslake Holidays Limited | Agriculture & fishing | 2014 |
| Kingsleigh Consultancy Services Ltd | Professional & scientific | 2013 |
| Kingsmead Equestrian Limited | Professional & scientific | 1983 |
| Kingsmead Glass and Glazing Limited | Construction | 2020 |
| Kingsmead Road (Loudwater) Management Company Limited | Real estate | 2014 |
| Kingsmead Testing Services Limited | Professional & scientific | 2007 |
| Kingswood Design and Build Ltd | Construction | 2020 |
| Kingswood Kitchen & Bedrooms Ltd | Manufacturing | 2024 |
| Kinq Ltd | Professional & scientific | 2025 |
| Kintsugi MC Limited | Professional & scientific | 2023 |
| Kinvest Group Ltd | Construction | 2025 |
| Kippersandslippers Ltd | Information & communication | 2013 |
| Kipuorm Ltd | Wholesale & retail | 2021 |
| Kiran House Management Company Limited | Real estate | 2022 |
| Kiran Singh Holdings Ltd | Financial services | 2024 |
| Kiran Singh Property Ltd | Real estate | 2024 |
| Kirstie Traas Associates Limited | Professional & scientific | 2019 |
| Kismot Ltd | Hospitality | 2024 |
| Kitchen Renewal Service Ltd | Administrative & support | 2022 |
| Kitchen Talent Ltd | Administrative & support | 2018 |
| Kitify Limited | Wholesale & retail | 2025 |
| Kiwi Controls Ltd | Professional & scientific | 2022 |