| Koala Digital Ltd | Professional & scientific | 2017 |
| Koell UK Limited | Wholesale & retail | 2013 |
| Koffie Health Ltd | Other services | 2017 |
| Koka Construction Ltd | Construction | 2014 |
| KOKI.UK2022 Ltd | Hospitality | 2022 |
| Kokpitt Ltd | Information & communication | 2019 |
| Kolyma Limited | Real estate | 2015 |
| Konda Property Limited | Real estate | 2018 |
| Konradt Fitness Limited | Arts & recreation | 2026 |
| Kootchy Products Limited | Wholesale & retail | 2011 |
| Korban Consulting Limited | Professional & scientific | 2024 |
| Korber and Clarke Capital Management Limited | Financial services | 2020 |
| Korean Katsu Limited | Hospitality | 2022 |
| Kortec IT Ltd | Information & communication | 2023 |
| Koryu Limited | Hospitality | 2018 |
| KOS 5B Limited | Hospitality | 2009 |
| Koshvi Ltd | Wholesale & retail | 2025 |
| Kott Enterprise Services Limited | Information & communication | 2007 |
| Kovaccare Ltd | Health & social care | 2018 |
| Kpmsuk Limited | Health & social care | 2006 |
| Kpume Properties Limited | Real estate | 2020 |
| Kraken Dive Team Ltd | Arts & recreation | 2023 |
| Kratostech Solutions Ltd | Information & communication | 2024 |
| Krea Consults Limited | Information & communication | 2017 |
| Krex Talents Ltd | Professional & scientific | 2018 |
| KRH Technical Services Limited | Extraterritorial | 2021 |
| Kris Sonnenberg Ltd | Transport & logistics | 2020 |
| Kristi Hima Ltd | Transport & logistics | 2022 |
| Krithi Homes Limited | Real estate | 2024 |
| Krithi Technologies Limited | Information & communication | 2025 |
| Krizd Ltd | Health & social care | 2024 |
| KRP Project Services Ltd | Professional & scientific | 2013 |
| KRS Infotech Limited | Information & communication | 2013 |
| KRW Accountants Limited | Professional & scientific | 2009 |
| Kryztel Homes Limited | Real estate | 2001 |
| KS Martin Rigging Ltd | Construction | 2019 |
| KS Windows Supplied Ltd | Construction | 2022 |
| KSB Training Limited | Education | 2014 |
| Kshema Limited | Real estate | 2024 |
| KSI Online Limited | Other services | 2013 |
| KSM Takeway Limited | Hospitality | 2025 |
| Ksnp Limited | Hospitality | 2025 |
| KSP Education Improvement Services Ltd | Education | 2022 |
| KSS Home Care Limited | Health & social care | 2023 |
| KTB Solutions (UK) Limited | Manufacturing | 2013 |
| KTG Distribution Ltd | Wholesale & retail | 2015 |
| KTL Auto Ltd | Wholesale & retail | 2024 |
| Kube Kitchens Limited | Wholesale & retail | 2011 |
| Kube Kitchens Upminster Ltd | Wholesale & retail | 2012 |
| Kubhas Estates Ltd | Real estate | 2023 |
| Kukkdi Ltd | Wholesale & retail | 2021 |
| Kukri Global Ltd | Financial services | 2022 |
| Kullafi Probuilders Ltd | Construction | 2025 |
| Kumar Consultancies Limited | Health & social care | 2014 |
| Kumars Infotech Ltd | Information & communication | 2022 |
| Kumpir Kitchen Ltd | Hospitality | 2025 |
| Kuningi Ltd | Information & communication | 2024 |
| Kuredu Investments Ltd | Real estate | 2024 |
| Kurichan Limited | Real estate | 2022 |
| Kutz AMC Limited | Other services | 2002 |
| KUU Media Ltd | Information & communication | 2021 |
| KV Professional Services Ltd | Health & social care | 2018 |
| KV Property Rentals Ltd | Real estate | 2023 |
| Kwality Traders Limited | Wholesale & retail | 2024 |
| Kwan Trading Ltd | Wholesale & retail | 2024 |
| KWD Grab Hire Essex and Suffolk Ltd | Administrative & support | 2019 |
| KWD Grab Hire Limited | Administrative & support | 2017 |
| KWD Surveyors LLP | | 2012 |
| Kwiksim Limited | Information & communication | 2025 |
| Kyle Building Solutions Ltd | Construction | 2022 |
| Kyrano (Thunderbird) Limited | Health & social care | 2013 |
| L & C Taylor Properties Ltd | Real estate | 2020 |
| L & C Transformations Ltd | Manufacturing | 2011 |
| L & K Haulage Limited | Transport & logistics | 2016 |
| L & M Engineering Services Limited | Manufacturing | 2015 |
| L & R Plant Limited | Wholesale & retail | 2003 |
| L & R Property Management Ltd | Real estate | 2022 |
| L a Giles & Sons Limited | Construction | 2007 |
| L C Car Sales Ltd | Wholesale & retail | 2021 |
| L Crosby Builders Ltd | Construction | 2015 |
| L Hunt Services Ltd | Construction | 2025 |
| L J Brewer Limited | Professional & scientific | 2013 |
| L J Rose Accounting Ltd | Professional & scientific | 2012 |
| L Robson Ltd | Construction | 2019 |
| L S Hire (East Anglia) Ltd | Administrative & support | 2018 |
| L S Landscape Solutions Ltd | Administrative & support | 2017 |
| L Taylor Roofing and Property Services Limited | Construction | 2025 |
| L Trump Ltd | Professional & scientific | 2018 |
| L&C Property Works Ltd | Real estate | 2025 |
| L&L Property Partnership Ltd | Real estate | 2025 |
| L&M Partnership Limited | Financial services | 2026 |
| L&S Contracts Limited | Construction | 2023 |
| L&V Business Accounting Ltd | Professional & scientific | 2025 |
| L&Z Rentals Ltd | Real estate | 2023 |
| L. J. Crisp Ltd. | Transport & logistics | 2013 |
| L. R. Blomfield Limited | Real estate | 1992 |
| L. W. MAY and SON (P&H) Limited | Construction | 2007 |
| L.A.W. Refurbishments Ltd | Construction | 2017 |
| L.B. Plumbing and Heating Limited | Construction | 2003 |
| L.B.Ch. Haulage Ltd | Transport & logistics | 2024 |