| Kesh Four Limited | Real estate | 2022 |
| Keston & Keston Ltd | Financial services | 2017 |
| Keston Builders Merchants Ltd | Wholesale & retail | 2023 |
| Kevin Garrett Solutions Limited | Construction | 2015 |
| KEW Group Limited | Real estate | 2016 |
| KEW Windows Ltd | Construction | 2017 |
| Kewani Limited | Hospitality | 2024 |
| Keyspace Living Ltd | Real estate | 2025 |
| Keystones Construction Limited | Construction | 2024 |
| KF Surgery Ltd | Health & social care | 2020 |
| KFM Holdings Limited | Wholesale & retail | 2008 |
| KG Professional Services Ltd | Professional & scientific | 2018 |
| KGM Express Limited | Transport & logistics | 2013 |
| KGS Delivery Ltd | Transport & logistics | 2020 |
| KGS Rentals Ltd | Administrative & support | 2024 |
| KH Consulting Services Ltd | Information & communication | 2018 |
| Khair Solutions Limited | Information & communication | 2019 |
| KHB Builders & Decorators Ltd | Construction | 2007 |
| KHB7 Limited | Financial services | 2020 |
| Khlfa Ltd | Wholesale & retail | 2024 |
| Khorsandcapital Ltd | Professional & scientific | 2020 |
| Khwaja Limited | Information & communication | 2014 |
| Kiano Spaces Limited | Real estate | 2019 |
| Kiatz-Joinerys and Resources Limited | Manufacturing | 2025 |
| Kibalii Partners Ltd | Professional & scientific | 2025 |
| Kibritci Marin Ltd | Extraterritorial | 2025 |
| Kicc the Open Door | Other services | 2011 |
| Kiem Tang Ltd | Administrative & support | 2015 |
| Kilgour French & Stanbury Limited | Manufacturing | 2021 |
| Killer Filler Ltd | Information & communication | 2025 |
| Kimani Logistics Ltd | Transport & logistics | 2025 |
| Kimar Property Limited | Real estate | 2018 |
| Kimberley Gate Management Company Limited | Households | 1993 |
| KIN Live Limited | Arts & recreation | 2026 |
| KIN Support Services Ltd | Real estate | 2025 |
| Kinder Play Cafe Ltd | Hospitality | 2025 |
| Kindor Trading Co., Ltd | Extraterritorial | 2025 |
| Kinekta Limited | Administrative & support | 2018 |
| Kinematix Solutions Ltd | Information & communication | 2012 |
| Kingdom Simsek Ltd | Hospitality | 2025 |
| Kingfisher Building Maintenance Ltd | Administrative & support | 2016 |
| Kingfisher Educational Consultancy Limited | Administrative & support | 2009 |
| Kingsborough Management Services Ltd | Households | 2021 |
| Kingsland Investment Consultants Limited | Financial services | 2011 |
| Kingsley House Limited | Households | 2008 |
| Kingsquest Limited | Households | 1995 |
| Kingsway London Limited | Real estate | 1990 |
| Kingswood Place (Bromley) Management Company Limited | Households | 2008 |
| Kingzsparkz Limited | Manufacturing | 2024 |
| Kinloch House Bampton Road Limited | Real estate | 2018 |
| Kinloch Residents Limited | Households | 1992 |
| Kino Course Education Ltd | Education | 2025 |
| Kino Design Limited | Professional & scientific | 2014 |
| Kinopost Limited | Information & communication | 2024 |
| Kipa Bloom Ltd | Hospitality | 2025 |
| Kirlands Limited | Real estate | 2010 |
| Kitcaboodle Ltd | Wholesale & retail | 2024 |
| Kitemoor Limited | Financial services | 2022 |
| Kiwi Franco Consulting Limited | Information & communication | 2017 |
| Kizdayzee Limited | Wholesale & retail | 2017 |
| KJK Associates Limited | Professional & scientific | 2017 |
| Kjt-Construction Support Ltd | Construction | 2007 |
| Kjvj Staffing Limited | Administrative & support | 2021 |
| Kjys Limited | Financial services | 2015 |
| Kkvb Services Ltd | Wholesale & retail | 2014 |
| KL DB LLP | | 2024 |
| Klaar Smart Materials Ltd | Professional & scientific | 2024 |
| Kladi Limited | Construction | 2026 |
| Kleon Construction Ltd | Construction | 2024 |
| Klimovsky Limited | Information & communication | 2012 |
| Klinical Ltd | Professional & scientific | 2010 |
| Klondike Properties Limited | Real estate | 2024 |
| KLP Group Ltd | Financial services | 2025 |
| KLV Logistics Ltd | Transport & logistics | 2022 |
| Klynk Ventures Ltd | Administrative & support | 2017 |
| KM & Group Limited | Wholesale & retail | 2025 |
| KM Korkmaz Fruit & VEG Limited | Wholesale & retail | 2019 |
| KMD Accounting Services Limited | Professional & scientific | 2020 |
| KN Electrical Contractors Limited | Construction | 2019 |
| Knight and Edwards Limited | Construction | 2010 |
| Knight Architectural Works Ltd | Professional & scientific | 2025 |
| Knight Building Limited | Construction | 2016 |
| Knights Enterprise Limited | Real estate | 2015 |
| KNL Homes Ltd | Real estate | 2022 |
| KNM Management Ltd | Professional & scientific | 2014 |
| Knms Properties Limited | Real estate | 2023 |
| Knoll Residents Association Limited(The) | Real estate | 1971 |
| Knots Arts CIC | Arts & recreation | 2013 |
| Knotso Limited | Arts & recreation | 2021 |
| Knowleds Consulting Limited | Professional & scientific | 2022 |
| Knowlwood Trading LLP | | 2006 |
| KO Quants Limited | Other services | 2011 |
| Kofosanyahair Ltd | Other services | 2021 |
| Kolan Logistics UK Ltd | Wholesale & retail | 2024 |
| Kolev & Co Limited | Other services | 2012 |
| Komando Sons Limited | Real estate | 2024 |
| Kong (Brother) Ltd | Hospitality | 2018 |
| Kong Design Limited | Professional & scientific | 2017 |
| Konnect Konnects Ltd | Administrative & support | 2023 |
| Konoff Ltd | Construction | 2013 |