| Knights Railway Limited | Hospitality | 2025 |
| Knightsbridge Court (Chesterfield) Management Company Limited | Households | 2022 |
| Knightsbridge Garage Limited | Wholesale & retail | 2003 |
| Knightsbridge Real Estate Ltd | Professional & scientific | 2014 |
| Knightsbridge Solicitors Ltd | Professional & scientific | 2013 |
| Knit Nottingham Ltd | Wholesale & retail | 2024 |
| Knittingham Limited | Manufacturing | 1984 |
| Knittingham of Nottingham Ltd | Manufacturing | 2017 |
| Knjoro Ltd | Health & social care | 2018 |
| KNK Scrap Metal Recycling Limited | Wholesale & retail | 2026 |
| KNL Enterprises Limited | Real estate | 2016 |
| Knoemi Limited | Other services | 2025 |
| Knovatech Services Ltd | Professional & scientific | 2021 |
| Know Ltd. | Education | 2014 |
| Knowle House Property Ltd | Real estate | 2024 |
| Knowledge Explorer Ltd | Extraterritorial | 2013 |
| Knowles (Group Operations) Limited | Professional & scientific | 1993 |
| Knowles Electrical Limited | Construction | 2015 |
| Knowles Holdings (Nott'M) Limited | Financial services | 2025 |
| Knowles Medical Limited | Health & social care | 2017 |
| Knox & SON Limited | Extraterritorial | 1976 |
| KNR Plumbing & Heating Ltd | Construction | 2022 |
| KNS Electrical Services Ltd. | Construction | 2018 |
| Knyte Group Ltd | Information & communication | 2024 |
| Koala KLUBS1 Ltd | Health & social care | 2019 |
| Koco Aesthetics Limited | Other services | 2023 |
| Koco Homes Ltd | Real estate | 2017 |
| Koda Systems Ltd | Administrative & support | 2025 |
| Kode Group Ltd | Extraterritorial | 2023 |
| Kodex Limited | Information & communication | 1998 |
| Kodo Barbers Ltd | Other services | 2022 |
| Koffeemakerz Ltd | Information & communication | 2020 |
| Kogut Ltd | Transport & logistics | 2016 |
| Kojima Seimen Ltd | Hospitality | 2024 |
| Kokode Ltd | Wholesale & retail | 2024 |
| Kokoro JNJ Ltd | Hospitality | 2022 |
| Koku Ltd | Real estate | 2018 |
| KOL AI Ltd | Information & communication | 2025 |
| Kollasoft Ltd | Information & communication | 2017 |
| Kolpak Refrigeration (UK) Limited | | 1983 |
| Komarski Ltd | Wholesale & retail | 2013 |
| Komazon Limited | Wholesale & retail | 2021 |
| Kombbans Holdings Limited | Hospitality | 2022 |
| Komdex Ltd | Construction | 2025 |
| Komfort Cars Limited | Transport & logistics | 2023 |
| Komfort Fleet Limited | Health & social care | 2020 |
| Komorebi Wellness Limited | Health & social care | 2025 |
| Komos Capital Ltd | Real estate | 2025 |
| Komplete Beatz Ltd | Arts & recreation | 2024 |
| Kompress Holdings Limited | Manufacturing | 1978 |
| Kompress International Limited | Extraterritorial | 1974 |
| Kompress Limited | Extraterritorial | 1973 |
| Komura Holdings Limited | Financial services | 2020 |
| KON Fish Bar Ltd | Hospitality | 2018 |
| Konan Limited | Administrative & support | 2022 |
| Konceptua IP Ltd | Wholesale & retail | 2025 |
| Konduru Ltd | Real estate | 2023 |
| Kondy Logistics Ltd | Transport & logistics | 2019 |
| Konex Group Limited | Administrative & support | 2018 |
| Konex Media Ltd | Professional & scientific | 2015 |
| Konfir (UK) Ltd | Information & communication | 2021 |
| Konfir Verify Ltd | Professional & scientific | 2023 |
| Konfluence Technology Ltd | Information & communication | 2021 |
| Konjoda Limited | Real estate | 1977 |
| Konmex Limited | Professional & scientific | 2001 |
| Konnex Networks Limited | Information & communication | 2000 |
| Konrado Limited | Health & social care | 2018 |
| Konsultech Engineering Services Ltd | Professional & scientific | 2022 |
| Konsultix Ltd | Information & communication | 2009 |
| Kontentforlifetsyle Limited | Manufacturing | 2024 |
| Kontoor South Wales Limited | Manufacturing | 1980 |
| Kontrolla Limited | Information & communication | 2001 |
| Kool HO Ltd | Administrative & support | 2025 |
| Kool Kidz Cutz Ltd | Other services | 2019 |
| Kool Paye Ltd | Administrative & support | 2025 |
| Koolaid Holdings Limited | Financial services | 2025 |
| Koolpug Ltd | Wholesale & retail | 2019 |
| Kope-Medics Nottingham Ltd | Health & social care | 2023 |
| Kopek Security and Facilities Ltd | Administrative & support | 2020 |
| Kopila Limited | Real estate | 2025 |
| Koppa Hairdressing Ltd | Wholesale & retail | 2013 |
| Korahi Night Limited | Hospitality | 2025 |
| Kordz Europe Ltd | Wholesale & retail | 2015 |
| Korean Cuisine Limited | Hospitality | 2024 |
| Korean Delights Limited | Hospitality | 2021 |
| Koren Engineering Limited | Professional & scientific | 2025 |
| Koros Properties Limited | Real estate | 2020 |
| Kortec Coatings Limited Partnership | | 2007 |
| Koru Bidco Limited | Financial services | 2019 |
| Koru Midco 1 Limited | Financial services | 2019 |
| Koru Midco 2 Limited | Financial services | 2019 |
| Koru Topco Limited | Financial services | 2019 |
| Kosh Concepts Ltd | Manufacturing | 2025 |
| Kosh Tech House Ltd | Information & communication | 2025 |
| Kosharah Developments Ltd | Construction | 2024 |
| Koshiland Ltd | Wholesale & retail | 2025 |
| Kostaco Ltd | Hospitality | 2024 |
| KOT - UK Educational Services & Tours Ltd | Wholesale & retail | 2019 |
| KOT Systems Limited | Information & communication | 2013 |
| Kothari Medical Services Ltd | Health & social care | 2012 |