| K9 Sentinel Ltd | Administrative & support | 2024 |
| K9 Shield Security Services Ltd | Administrative & support | 2023 |
| KA Building Products Limited | Wholesale & retail | 2026 |
| KA Decorating Ltd | Construction | 2026 |
| Ka&Mt Limited | Construction | 2015 |
| Kaaasa Property Limited | Real estate | 2023 |
| Kaad's Accessory Ltd | Wholesale & retail | 2026 |
| Kaas Network Limited | Information & communication | 2024 |
| Kaaz Estates Limited | Real estate | 1998 |
| KAB Seating Limited | Manufacturing | 1987 |
| Kabanas Bar Ltd | Hospitality | 2015 |
| Kabb Investment Ltd | Real estate | 2022 |
| Kaboodle Limited | Administrative & support | 2006 |
| Kaby Construction Limited | Construction | 2025 |
| Kaczoruk Ltd | Transport & logistics | 2020 |
| Kadan Computers Limited | Information & communication | 2013 |
| Kaelan Limited | Real estate | 1985 |
| Kaffeine Digital Limited | Professional & scientific | 2016 |
| Kagata Limited | Professional & scientific | 2014 |
| KAH Logistics Ltd | Transport & logistics | 2014 |
| Kaha Logistics Solutions Ltd | Professional & scientific | 2023 |
| Kaida Technology Limited | Manufacturing | 2006 |
| Kaidoz Limited | Information & communication | 2018 |
| Kaienna Ltd | Real estate | 2025 |
| Kaig Ltd | Real estate | 2024 |
| Kaintura Properties Ltd | Real estate | 2019 |
| Kairos Consultancy and Training Ltd | Professional & scientific | 2019 |
| Kairosent Limited | Information & communication | 2015 |
| Kaizen Commercial Limited | Professional & scientific | 2023 |
| Kaizen Football Ltd | Education | 2020 |
| Kaizen Nutrition Ltd | Manufacturing | 2025 |
| Kajzer Trans Ltd | Transport & logistics | 2021 |
| Kaka Estates Ltd | Real estate | 2023 |
| Kaka Farm Ltd | Information & communication | 2020 |
| Kaka Stores Ltd | Wholesale & retail | 2014 |
| Kaka Supermarket UK Ltd | Wholesale & retail | 2023 |
| Kalanga Dreams Limited | Health & social care | 2019 |
| Kalco Limited | Hospitality | 2021 |
| Kalisz Trans Limited | Transport & logistics | 2013 |
| Kalkaji Pharmacon Limited | Professional & scientific | 2016 |
| Kally Ltd | Wholesale & retail | 2018 |
| Kaly Solutions Ltd | Administrative & support | 2026 |
| Kalyxbest Limited | Health & social care | 2024 |
| KAM Construction Limited | Construction | 2002 |
| KAM Electrical Limited | Construction | 2016 |
| KAM5 Ltd | Hospitality | 2025 |
| Kamal Mistry Limited | Health & social care | 2018 |
| Kamboocha Limited | Wholesale & retail | 2023 |
| Kamel Group Limited | Professional & scientific | 2021 |
| Kamihire Ltd | Other services | 2024 |
| Kamil G Transport Ltd | Transport & logistics | 2019 |
| Kamimotors Ltd | Other services | 2026 |
| Kamini Fletcher Limited | Professional & scientific | 2001 |
| Kamrans Property Services Ltd | Households | 2021 |
| Kams Tree Care Ltd | Agriculture & fishing | 2018 |
| Kana Enterprise Consultancy Limited | Information & communication | 2019 |
| Kanaui Ltd | Information & communication | 2026 |
| Kandall Medical Limited | Real estate | 2014 |
| Kandap (Leicester) Limited | Professional & scientific | 2022 |
| Kandap (Lincs) Limited | Professional & scientific | 2024 |
| Kandap (Northampton) Limited | Professional & scientific | 2023 |
| Kandap (Warwickshire) Limited | Professional & scientific | 2024 |
| Kandap Limited | Administrative & support | 2025 |
| Kander Maglev Ltd | Professional & scientific | 2026 |
| Kandll Properties Ltd | Real estate | 2024 |
| Kandou BUS Limited | Manufacturing | 2016 |
| Kaotemo UK Ltd | Professional & scientific | 2020 |
| KAP Technical Services Limited | Administrative & support | 2021 |
| Kapek Ltd | Professional & scientific | 2018 |
| Kapena Property Holdings Ltd | Real estate | 2026 |
| Kapital Technologies Limited | Financial services | 2025 |
| Kapron Transport Limited | Transport & logistics | 2011 |
| Karak Chaii MK Limited | Hospitality | 2023 |
| Karak Chaii Northampton Limited | Hospitality | 2023 |
| Karelle Recruiting Limited | Professional & scientific | 2022 |
| Karen Hawker Assessments Limited | Health & social care | 2024 |
| Karia Enterprises Limited | Other services | 1993 |
| Karibacare Ltd | Health & social care | 2021 |
| Karim Property Investments Limited | Construction | 2025 |
| Karis Care Limited | Health & social care | 2022 |
| Karis Enterprise Limited | Administrative & support | 2022 |
| Karis Properties Enterprise Ltd | Real estate | 2025 |
| Karl Bates Roofing Limited | Construction | 2016 |
| Karl Goshawk Racing Ltd | Arts & recreation | 2017 |
| Karlatrans Ltd | Transport & logistics | 2019 |
| Karma Life Coaching Ltd | Education | 2023 |
| Karma-G Limited | Financial services | 2019 |
| Karmenz Ltd | Other services | 2016 |
| Kars Garage Services Limited | Wholesale & retail | 2017 |
| Kartell UK Limited | Wholesale & retail | 2008 |
| Kartoffel Films Ltd | Information & communication | 2012 |
| Karva CAB Service Ltd | Transport & logistics | 2020 |
| Karwan Car Sales 24/7 Ltd | Wholesale & retail | 2026 |
| Kash Retailers Ltd | Wholesale & retail | 2018 |
| Kasiluv Entertainment Limited | Arts & recreation | 2018 |
| Kaspiro Service Ltd | Construction | 2021 |
| Kass's Entertainment Ltd | Hospitality | 2017 |
| Kassandra Ltd | Transport & logistics | 2024 |
| Kassem Properties Ltd | Real estate | 2019 |
| Kasturi Traders Ltd | Wholesale & retail | 2021 |