| JW Building & Landscaping Services Limited | Construction | 2019 |
| Jwoolf Properties Limited | Real estate | 2025 |
| K & AS Financial Services Ltd | Financial services | 2019 |
| K & G International Limited | Wholesale & retail | 2017 |
| K & M Decorators Limited | Construction | 2000 |
| K & M Hybrid Limited | Wholesale & retail | 2006 |
| K & Y Motor Ltd | Wholesale & retail | 2023 |
| K a B Contracting Limited | Agriculture & fishing | 2014 |
| K Gems Cleaning Service Ltd | Administrative & support | 2022 |
| K J Carter Limited | Construction | 1999 |
| K Majestic Properties Limited | Real estate | 2025 |
| K S and Daughters Limited | Hospitality | 2019 |
| K&G Food and Wine Ltd | Wholesale & retail | 2025 |
| K&M Suppliers Ltd | Wholesale & retail | 2025 |
| K'Z Dance Entertainment Limited | Other services | 2015 |
| K- Gymnastics Ltd | Arts & recreation | 2018 |
| K. Macdonald Engineering Design Services Limited | Professional & scientific | 2007 |
| K.B.K Construction Ltd | Construction | 2018 |
| K.K. Hemel Hempstead Limited | Manufacturing | 2010 |
| K.U.O Enterprises Ltd | Hospitality | 2026 |
| K2 Enterprises Limited | Hospitality | 2008 |
| K72 Communications Limited | Professional & scientific | 2023 |
| K9 Harkin Dog Training Ltd | Other services | 2018 |
| Kabs Builder Ltd | Construction | 2023 |
| Kaffex Care 24/7 Ltd | Administrative & support | 2026 |
| Kai-Tiao Ltd | Real estate | 2024 |
| Kairos Contract Management (UK) Ltd | Professional & scientific | 2026 |
| Kaishi Amanda Davis Limited | Financial services | 2025 |
| Kalessi Constructions Limited | Construction | 2017 |
| Kallisto Properties Ltd | Administrative & support | 2024 |
| Kalo Builders Ltd | Construction | 2023 |
| Kamillo Construction Ltd | Construction | 2011 |
| Kand Bros Ltd | Hospitality | 2022 |
| Kanyeco Limited | Arts & recreation | 2014 |
| KAP Restaurants Ltd | Hospitality | 2022 |
| Kara Prime Investments Ltd | Households | 2025 |
| Karamark Properties Limited | Real estate | 1999 |
| Karen Bosher Advisory Limited | Professional & scientific | 2023 |
| Karson Living Ltd | Construction | 2026 |
| Karvi Solutions Ltd | Information & communication | 2026 |
| Kash Suppliers Limited | Wholesale & retail | 2025 |
| Kassem's Ltd | Hospitality | 2025 |
| Katana Management Company Limited | Households | 1997 |
| Katy Green Ltd | Professional & scientific | 2026 |
| KAY Estates Limited | Real estate | 2016 |
| KBF Properties Ltd | Real estate | 2025 |
| KBI Solutions Ltd | Administrative & support | 2026 |
| KBK Investment Properties Ltd | Real estate | 2026 |
| KC Films Limited | Information & communication | 2014 |
| KC Nails Ltd | Other services | 2019 |
| KC Rail Ltd | Extraterritorial | 2024 |
| KC Tech Limited | Information & communication | 2011 |
| KCB Marketing Ltd | Professional & scientific | 2021 |
| KCB Pensions Ltd | Financial services | 2025 |
| KCB Personal Group Ltd | Professional & scientific | 2020 |
| Kciuk Property Ltd | Real estate | 2025 |
| KD Innovations Ltd | Administrative & support | 2026 |
| KDG Holdings Limited | Extraterritorial | 1985 |
| Keenok Ltd | Wholesale & retail | 2012 |
| Keephatch Gardens (Wokingham) Management Company Limited | Households | 2018 |
| Kehorne Limited | Information & communication | 2008 |
| Keldar Limited | Professional & scientific | 2018 |
| Kelhar Holdings Limited | Real estate | 2025 |
| Kellmatt Limited | Manufacturing | 1991 |
| Kelmic Ltd | Construction | 2020 |
| Kelmic Plant Hire Ltd | Administrative & support | 2020 |
| Kelmuir Flat Management Company Limited | Households | 1976 |
| Kelvin Archer Limited | Professional & scientific | 2007 |
| Kenavon Drive (Reading) Management Company Limited | Households | 2015 |
| Kendallco Limited | Arts & recreation | 2014 |
| Kenilworth Gate Management Company Limited | Households | 2023 |
| Kenley Park Management Company Limited | Households | 2003 |
| Kenly's Supreme Foods Co Ltd | Manufacturing | 2020 |
| Kenmore Gardens Maintenance Services Ltd. | Households | 2009 |
| Kenmore UK Ltd. | Financial services | 1973 |
| Kennedy Consultants Ltd | Professional & scientific | 2022 |
| Kennedy Engineering Solutions Limited | Professional & scientific | 2007 |
| Kenneth O'Donnell Ltd | Extraterritorial | 2025 |
| Kensal Limited | Extraterritorial | 2016 |
| Kensington Trade Limited | Wholesale & retail | 2011 |
| Kensington Hand Car Wash Limited | Administrative & support | 2013 |
| Kent Drywall (UK) Limited | Construction | 2022 |
| Kent Salon LLP | | 2011 |
| Kenwick Estates Limited | Extraterritorial | 1991 |
| Kenwick Park Hotel Limited | Hospitality | 1992 |
| Kenwick Property Sales Ltd | Real estate | 1997 |
| Kenwick Woods Limited | Real estate | 1993 |
| Kenya Diaspora UK Association | Professional & scientific | 2019 |
| Kerri Lipsitz Limited | Professional & scientific | 2012 |
| Kerry Jack Limited | Professional & scientific | 2011 |
| Kevin Keany Ltd | Financial services | 2013 |
| Kevin Wilks Ltd | Administrative & support | 2020 |
| Kewd Consulting Ltd | Professional & scientific | 2022 |
| Keyhive Realty Ltd | Real estate | 2026 |
| Keynet Solutions Limited | Professional & scientific | 2018 |
| Keynex Limited | Construction | 2016 |
| Keynsham Residents Management Company Ltd | Households | 2019 |
| Keza Technologies Ltd | Information & communication | 2025 |
| KG2 Ltd | Real estate | 2025 |
| Kgeorgiev Ltd | Construction | 2017 |