| Jupiter Investments Limited | Real estate | 1997 |
| Jurnni International Ltd | Construction | 2015 |
| Just a Little Company (Care and Support at Home) Ltd | Health & social care | 2016 |
| Just Battery Technologies Ltd | Wholesale & retail | 2025 |
| Just Dental Medicolegal Experts Ltd | Health & social care | 2016 |
| Just for YOU Gaming BUS Ltd | Wholesale & retail | 2020 |
| Just Vauxhalls Limited | Other services | 2019 |
| Just WOT U Need Ltd | Administrative & support | 2006 |
| Justan Limited | Wholesale & retail | 2024 |
| Juttex Limited | Wholesale & retail | 2025 |
| Juttperfume Limited | Wholesale & retail | 2025 |
| JUV Limited | Wholesale & retail | 2025 |
| JVC Construction & Facility Management Limited | Construction | 2025 |
| JVD Elite Ltd | Wholesale & retail | 2025 |
| JW Assets Limited | Real estate | 2023 |
| JW Docking & SON (Funeral Furnishers) Limited | Extraterritorial | 2009 |
| JW NW Limited | Professional & scientific | 2018 |
| JWO Properties Ltd | Real estate | 2024 |
| Jwsj Ltd | Real estate | 2025 |
| K C Decorators Limited | Construction | 2002 |
| K Granite Limited | Manufacturing | 2010 |
| K J Builders Ltd | Construction | 2023 |
| K L Butchers Ltd | Wholesale & retail | 2020 |
| K&A Lancashire Limited | Wholesale & retail | 2018 |
| K&T Packaging Ltd | Other services | 2025 |
| K. 804 Ltd | Wholesale & retail | 2024 |
| K3I Wholesale Ltd | Wholesale & retail | 2017 |
| K44 Limited | Hospitality | 2016 |
| K50 Security Ltd | Administrative & support | 2018 |
| KA1 Pharma Limited | Health & social care | 2022 |
| Kaberry Homes Limited | Construction | 1950 |
| Kabtech Electrical Solutions Limited | Other services | 2023 |
| Kaftrader Ltd | Wholesale & retail | 2025 |
| Kafzaltraders Ltd | Transport & logistics | 2025 |
| KAG Courier Ltd | Transport & logistics | 2025 |
| Kago Logistik Ltd | Transport & logistics | 2026 |
| KAI Care Solutions Limited | Health & social care | 2016 |
| KAI Executives Ltd | Administrative & support | 2026 |
| Kainaats Kebabs Limited | Manufacturing | 2021 |
| Kalys Carpets Limited | Wholesale & retail | 2017 |
| KAM Auto Smart Ltd | Wholesale & retail | 2025 |
| Kandor Ltd | Professional & scientific | 2019 |
| Kandy Kitchen Creations Ltd | Manufacturing | 2019 |
| KAP Diagnostics.Com Limited | Wholesale & retail | 2010 |
| KAP Estates Limited | Financial services | 2014 |
| Kapila Group Ltd | Real estate | 2024 |
| Kar-Trans Ltd | Transport & logistics | 2019 |
| Kareem ALI Enterprises Ltd | Wholesale & retail | 2019 |
| Kartmann Ltd | Wholesale & retail | 2024 |
| Kashmir Cash & Carry Ltd | Wholesale & retail | 2023 |
| Kashmir Supermarket (Dewsbury) Ltd | Wholesale & retail | 2025 |
| Kashmir Traders Limited | Wholesale & retail | 2025 |
| Kashmir Youth Project | Health & social care | 1989 |
| Kashmiri Productions UK CIC | Arts & recreation | 2023 |
| Kasim Bhatti Props Ltd | Wholesale & retail | 2025 |
| Kasper Trading Ltd | Wholesale & retail | 2018 |
| Kass Market 2 Ltd | Wholesale & retail | 2024 |
| Kassmura (UK) Ltd | Administrative & support | 2014 |
| Kastredz Ltd | Wholesale & retail | 2026 |
| Kataria Market Ltd | Wholesale & retail | 2022 |
| Kataria Property Limited | Real estate | 2024 |
| Kataria Sports Medicine and Properties Ltd | Arts & recreation | 2022 |
| Kates Kitchen Events Limited | Hospitality | 2026 |
| Katie Hamm Limited | Extraterritorial | 2023 |
| Kavyd Drone Services Ltd | Professional & scientific | 2024 |
| Kays Mortgage Solutions Ltd | Financial services | 2026 |
| Kazi Dynamics Ltd | Wholesale & retail | 2026 |
| Kazi Property Ltd | Real estate | 2026 |
| KB1514 Ltd | Financial services | 2017 |
| KCT Properties Ltd | Real estate | 2019 |
| Kdpc Electrical Limited | Construction | 2017 |
| Kdynamics Ltd | Professional & scientific | 2018 |
| Kearneys Driveways & Roofing Ltd | Construction | 2025 |
| Keats Brokers Limited | Administrative & support | 2013 |
| Kebab N Curry Buzz Ltd | Hospitality | 2026 |
| Kebabish Tandoori Ltd | Hospitality | 2025 |
| Kebana Takeaway & Restaurant Ltd | Hospitality | 2020 |
| Keep Clean Services Ltd | Administrative & support | 2022 |
| Keep IT Clean Commercial and Domestic Services Ltd | Administrative & support | 2022 |
| Keep Rising Dance Events Limited | Arts & recreation | 2025 |
| Keepers Green Management Company Limited | Real estate | 2018 |
| Keepgold Limited | | 1983 |
| KEN Rosebury Limited | Manufacturing | 1977 |
| KEN Taylor Group Limited | Financial services | 2020 |
| KEN Taylor Supplies Ltd. | Wholesale & retail | 1993 |
| Kendal Works (NW) Ltd | Real estate | 2026 |
| Kendalls Caravan Storage Limited | Transport & logistics | 2010 |
| Kennebec Limited | Hospitality | 2026 |
| Kenny GEE Property Limited | Real estate | 2022 |
| Kenya Orphans Foundation | Health & social care | 2021 |
| Kerbrook Limited | Construction | 2014 |
| Kerf Developments Limited | Manufacturing | 2002 |
| Kerogen Global Consulting Limited | Professional & scientific | 2025 |
| KES Transport Limited | Transport & logistics | 2017 |
| Kevin Wellington Decorators Limited | Construction | 2002 |
| Key 2 Holding Ltd | Financial services | 2026 |
| Key 2 Properties Limited | Real estate | 2024 |
| Key Property (NW) Limited | Real estate | 2020 |
| Keysec Limited | Wholesale & retail | 2025 |
| Keystone Primegate Properties Limited | Real estate | 2026 |