| Judge Properties Limited | Professional & scientific | 2001 |
| Julian Goldie LLP | | 2016 |
| Julie Cahill Educational Consultant Limited | Education | 2013 |
| Julius James Ltd | Construction | 2008 |
| Juniper Holdings Inc Limited | Real estate | 2016 |
| Junk Guys Ltd | Water & waste | 2025 |
| Jupiter Blueprint CIC | Information & communication | 2024 |
| Jupiter Chester Ltd | Real estate | 2025 |
| Jupitor Construct Limited | Wholesale & retail | 2026 |
| Just a Thought Foundation | Other services | 2018 |
| Just Essentials Ltd | Administrative & support | 2011 |
| Just JAM Recordings Limited | Arts & recreation | 2018 |
| Just the Good Stuff Limited | Wholesale & retail | 2026 |
| Justforme Preschool Limited | Education | 2012 |
| Justin Group Ltd | Construction | 2025 |
| Justin Heating Services Ltd | Construction | 2023 |
| Juventus Property Investments Limited | Real estate | 1997 |
| JW Mata Ltd | Wholesale & retail | 2025 |
| JYL Decoration Ltd | Construction | 2023 |
| JYN Property Limited | Real estate | 2016 |
| K and H Consultancy Limited | Administrative & support | 2012 |
| K C Logistik Limited | Transport & logistics | 2019 |
| K C S Contracts Limited | Public administration | 2011 |
| K Digital Online Ltd | Wholesale & retail | 2024 |
| K Direct Limited | Financial services | 2020 |
| K K London Properties Ltd | Real estate | 2020 |
| K M P Investments Limited | Real estate | 1997 |
| K POP UPS Limited | Wholesale & retail | 2025 |
| K Pret Ltd | Real estate | 2020 |
| K S Consultancy Limited | Professional & scientific | 2024 |
| K S Sypien Properties Ltd | Real estate | 2021 |
| K Services Limited | Professional & scientific | 2013 |
| K Sounds Group Limited | Professional & scientific | 2024 |
| K V Properties Limited | Real estate | 2011 |
| K&D Building Ltd | Construction | 2025 |
| K&S Property(Uk) Limited | Real estate | 2025 |
| K. H. a. Pashco Ltd | Real estate | 2020 |
| K.H.A Pashco Property LLP | | 2022 |
| K.K.Holdings Ltd. | Real estate | 2016 |
| K.Lyon(Furnishings)Limited | Construction | 1971 |
| K44 Studio Limited | Manufacturing | 2025 |
| K5 Investments Ltd | Real estate | 2026 |
| K:Ana Studio Ltd | Professional & scientific | 2023 |
| KA Capital Homes Limited | Real estate | 2020 |
| KA Optical Limited | Health & social care | 2014 |
| Ka-C Consulting Limited | Information & communication | 2009 |
| Kabul Travels and Tours Ltd | Administrative & support | 2026 |
| KAD International Limited | Wholesale & retail | 2023 |
| Kady Enterprise Limited | Financial services | 2018 |
| KAF Construction Ltd | Construction | 2022 |
| Kafza Limited | Real estate | 2024 |
| Kagersoft Ltd | Manufacturing | 2018 |
| KAI Trading Ltd | Wholesale & retail | 2022 |
| Kaimia Holdings Ltd | Real estate | 2022 |
| Kairos Associates Ltd | Information & communication | 2024 |
| Kairos Homes Limited | Real estate | 2016 |
| Kaizen Residential Care (UK) Limited | Health & social care | 2023 |
| Kajojam Limited | Real estate | 2013 |
| Kalbro Investments Limited | Real estate | 2003 |
| Kaleidoscope Advisory Limited | Administrative & support | 2019 |
| Kaleidoscope Group Ltd | Financial services | 2018 |
| Kaleidoscope Investments Limited | Financial services | 2015 |
| Kaleidoscope Mentoring Limited | Professional & scientific | 2019 |
| Kaleidoscope Recruitment Ltd. | Administrative & support | 2018 |
| Kalicson (UK) Limited | Wholesale & retail | 2005 |
| Kalp Enterprises Ltd | Professional & scientific | 2016 |
| Kalpadrum Market Ltd | Wholesale & retail | 2026 |
| Kalyani Cleaning Service Ltd | Administrative & support | 2026 |
| KAM Consultancy(Uk) Ltd | Professional & scientific | 2025 |
| KAM Estates Ltd | Real estate | 2016 |
| Kami Ltd | Wholesale & retail | 2025 |
| Kamranga Limited | Hospitality | 2019 |
| Kanaka Advisors Limited | Professional & scientific | 2018 |
| Kanani Imaging Ltd | Health & social care | 2025 |
| Kanay Limited | Real estate | 2017 |
| Kaniz International Limited | Wholesale & retail | 2018 |
| Kansagra Assets Limited | Financial services | 2026 |
| Kansara Investments Limited | Real estate | 2019 |
| Kantel Partners Ltd | Real estate | 2017 |
| Kapty Services Ltd | Hospitality | 2025 |
| KAR Venture Limited | Real estate | 2024 |
| Kara Autos Limited | Wholesale & retail | 2012 |
| Karamiya Properties Ltd | Real estate | 2018 |
| Karibu London Ltd | Hospitality | 2022 |
| Karma Accountants Limited | Professional & scientific | 2009 |
| Karma Exeter Limited | Hospitality | 2017 |
| Karr Consulting Limited | Professional & scientific | 2009 |
| Karura Properties Limited | Real estate | 2025 |
| Kasaka Hotels Management Limited | Hospitality | 2000 |
| Kasaka Properties Limited | Real estate | 2019 |
| Kascon Limited | Information & communication | 2019 |
| Kash Solutions Limited | Real estate | 2017 |
| Kashmir Peace Forum International Ltd | Extraterritorial | 2014 |
| Kasian Associates Ltd | Administrative & support | 2016 |
| Kastro 777 Limited | Real estate | 2020 |
| Kat's Consulting Ltd | Professional & scientific | 2025 |
| Kataco Properties Ltd | Real estate | 2025 |
| Katcs Advisory Ltd | Professional & scientific | 2026 |
| Kathleen Collective Limited | Wholesale & retail | 2024 |
| Kathleen Granados Limited | Professional & scientific | 2008 |