| Knight Property Holdings Group Limited | Real estate | 2025 |
| Knight's Paving & Landscaping Limited | Administrative & support | 2007 |
| Knight's Whistle Ltd | Professional & scientific | 2018 |
| Knightguard Limited | Administrative & support | 1997 |
| Knights Country Kitchens Ltd | Construction | 2009 |
| Knights Farms Limited | Agriculture & fishing | 1992 |
| Knights Foods Limited | Agriculture & fishing | 1998 |
| Knights Investments Ltd | Real estate | 2025 |
| Knights Sporting Limited | Wholesale & retail | 2004 |
| Knights-Smith Limited | Hospitality | 2025 |
| KNK Poultry Products Ltd | Wholesale & retail | 2016 |
| Knock Knock Verify Ltd | Wholesale & retail | 2026 |
| Knoll Design Engineering Limited | Manufacturing | 2010 |
| Knowledge City Partners Limited | Real estate | 2012 |
| Knowles (UK) Limited | Manufacturing | 1987 |
| Knowlton Estates Limited | Real estate | 2019 |
| Knox Road Apartments Management Company Limited | Households | 2020 |
| Knox Trading LLP | | 2011 |
| KOA Naturals Limited | Manufacturing | 2026 |
| Koala Bear Music Limited | Arts & recreation | 2005 |
| Kodi Jewels Limited | Wholesale & retail | 2025 |
| Kolkata Kitchen Ltd | Hospitality | 2016 |
| Kolo Creations Limited | Manufacturing | 2024 |
| Komada Ltd | Administrative & support | 2016 |
| Komaro Ltd | Construction | 2025 |
| Komerto Limited | Transport & logistics | 2020 |
| Komi Properties Ltd | Real estate | 2023 |
| Komo Bars Ltd | Hospitality | 2015 |
| Komo Woking Ltd | Hospitality | 2021 |
| Koncept Digital Media Limited | Information & communication | 2016 |
| Konoha Holdings Ltd | Financial services | 2021 |
| Kontor Property Investments Limited | Real estate | 2007 |
| Koobe Limited | Wholesale & retail | 2024 |
| Koppa Analytics Ltd | Professional & scientific | 2023 |
| KOR Holdings Limited | Information & communication | 2026 |
| Korliss Ltd | Real estate | 2021 |
| Kormbat Studios Ltd | Information & communication | 2025 |
| Koru Norwich Ltd | Other services | 2026 |
| Koru Security Solutions Ltd | Administrative & support | 2024 |
| Korutek Engineering Ltd | Manufacturing | 2016 |
| Koseph Ltd | Wholesale & retail | 2024 |
| Kosmas Taxi Ltd | Transport & logistics | 2025 |
| Kosta DJ Ltd | Transport & logistics | 2017 |
| Kostovski Ltd | Transport & logistics | 2022 |
| KP Accounting Limited | Professional & scientific | 2008 |
| KP Property Norfolk Ltd | Real estate | 2025 |
| KP Speed Limited | Transport & logistics | 2019 |
| KPA Consultants Limited | Professional & scientific | 2013 |
| KPC Food Ltd | Hospitality | 2026 |
| KPH Metalworks Ltd | Manufacturing | 2024 |
| KPL ENG Ltd | Real estate | 2015 |
| KPM Enterprise Limited | Wholesale & retail | 2024 |
| KPT Building Services Ltd | Construction | 2025 |
| KR Events Ltd | Hospitality | 2022 |
| Kravn Recoveries Ltd | Other services | 2023 |
| KRC Property Development Ltd | Real estate | 2023 |
| KRH Brickwork Ltd | Construction | 2021 |
| Krish Consultants Limited | Information & communication | 2022 |
| Kristina Decor Ltd | Manufacturing | 2025 |
| Kristoffer Care Ltd | Health & social care | 2023 |
| KRM Electrical Contractors Limited | Construction | 2017 |
| KRM Events Limited | Other services | 2013 |
| KRM Groundworks Limited | Construction | 2020 |
| Krmr Ltd | Health & social care | 2022 |
| Kronch Limited | Wholesale & retail | 2013 |
| Kruma Limited | Real estate | 2016 |
| KRV Trade Ltd | Transport & logistics | 2021 |
| Krygier & Miller Capital Group Ltd | Financial services | 2018 |
| Kryptonia People Solutions Limited | Administrative & support | 2024 |
| KS Cooling Ltd | Construction | 2021 |
| KS Import & Export Ltd | Wholesale & retail | 2025 |
| KS Lead Generation Ltd | Real estate | 2019 |
| KSI Holdings Ltd | Financial services | 2021 |
| KSI Technologies Limited | Administrative & support | 2005 |
| KSJ Motors & Transport Ltd | Wholesale & retail | 2025 |
| KSK Mainlaying Limited | Water & waste | 2011 |
| KSM Driving Tuition Ltd | Education | 2022 |
| KSN Couriers Ltd | Transport & logistics | 2026 |
| KST Incorporated Ltd | Construction | 2014 |
| KT & COE Recruit Ltd | Administrative & support | 2024 |
| KT Lake & SON Paving & Landscaping Limited | Construction | 2015 |
| KT Letting and Management Ltd | Real estate | 2017 |
| KU Connections Ltd | Financial services | 2025 |
| KUA Studio Ltd | Professional & scientific | 2024 |
| Kubik Limited | Extraterritorial | 2002 |
| Kubrito Foods Ltd | Hospitality | 2026 |
| KUK Economic Consulting Ltd | Professional & scientific | 2017 |
| KUK Sool UK BB Limited | Arts & recreation | 2023 |
| KUK Sool WON - United Kingdom Schools Limited | Arts & recreation | 2000 |
| Kukala Limited | Wholesale & retail | 2025 |
| Kumon Norfolk LLP | | 2023 |
| Kung FU Living Limited | Education | 2020 |
| Kunj Private Limited | Manufacturing | 2025 |
| KUNKI4 Ltd | Other services | 2019 |
| Kupfer Ltd | Professional & scientific | 2008 |
| Kurumuru Books LLP | | 2019 |
| Kustom Choppers Limited | Wholesale & retail | 2023 |
| KV Training Limited | Administrative & support | 2017 |
| Kvasir Ltd | Wholesale & retail | 2023 |
| KVI Capital Ltd | Extraterritorial | 2024 |