| Kardex Systems (UK) Limited | Manufacturing | 1969 |
| Karl Willett Ltd | Professional & scientific | 2014 |
| Karter Owens Ltd | Professional & scientific | 2025 |
| Kashman Holdings Limited | Financial services | 2023 |
| Kaste Makes Ltd | Information & communication | 2019 |
| Kaurus Limited | Administrative & support | 2002 |
| KAY and BE Limited | Wholesale & retail | 2012 |
| Kays Court Management Company Limited | Households | 1989 |
| Kb-Multisport Limited | Health & social care | 2023 |
| KBL Property Investment Limited | Real estate | 2025 |
| KBM Building Developments Ltd | Construction | 2024 |
| KBM Properties Limited | Construction | 2025 |
| KCM Cars Limited | Wholesale & retail | 2020 |
| KCW Funding Limited | Real estate | 2016 |
| KD Fine Art Solutions Ltd | Manufacturing | 2020 |
| Kdsa Holdings Ltd | Financial services | 2021 |
| Keeble Rentals UK Ltd | Real estate | 2026 |
| Keenan BC Ltd | Professional & scientific | 2024 |
| Keepence Ltd | Financial services | 2009 |
| Kelly Enforcement Ltd | Administrative & support | 2018 |
| Kelly Swallow Ltd | Arts & recreation | 2012 |
| Keloglan Dairy Limited | Wholesale & retail | 2007 |
| Keltan Holdings Ltd | Construction | 2019 |
| Keneth Peters Asset Management Limited | Real estate | 1990 |
| Kennett Court Freehold Limited | Other services | 2010 |
| Kennett Court Watford Limited | Households | 1992 |
| Kennington Park Road (K Point) Management Company Limited | Households | 2007 |
| Kestim Management Limited | Real estate | 2004 |
| Kevin Beadle Ltd | Construction | 2010 |
| Keymer Properties Ltd | Real estate | 2023 |
| KG Fiduciary Limited | Administrative & support | 2025 |
| Kgcorporate Limited | Administrative & support | 2012 |
| Kickstart Soccer Schools Limited | Administrative & support | 2013 |
| Kidbys Management Company Limited | Households | 2017 |
| Kids Collab Ltd | Information & communication | 2021 |
| Kiff Autos Ltd | Wholesale & retail | 2015 |
| Kikki-G Swimwear Limited | Manufacturing | 2020 |
| Kiln Trading Limited | Real estate | 2012 |
| Kinetic Insurance Brokers Limited | Financial services | 1976 |
| Kingdom Delicacies Ltd | Hospitality | 2025 |
| Kingfisher Building Services Limited | Construction | 2021 |
| Kingfisher Garden Solutions Limited | Administrative & support | 2021 |
| Kingsbury Automotive Ltd | Wholesale & retail | 2024 |
| Kingsbury Property (Roydon) Ltd | Real estate | 2011 |
| Kingsfield Management Company (Hertford) Limited | Households | 1994 |
| Kingsley Court (NW2) Freehold Limited | Administrative & support | 2016 |
| Kingsmead Security Limited | Information & communication | 2018 |
| Kingsway Commercial Interiors Limited | Construction | 2001 |
| Kinsman Mews Management Limited | Households | 2022 |
| Kirby & Cove Limited | Professional & scientific | 2000 |
| Kirit Limited | Hospitality | 2022 |
| Kiwi IT Solutions Limited | Information & communication | 2011 |
| Kkmg Systems Ltd | Construction | 2009 |
| KL Golden Ltd | Transport & logistics | 2019 |
| KLA Business Support Services Ltd | Administrative & support | 2007 |
| Klara 89 Ltd | Construction | 2023 |
| Klara Ascot Investments Limited | Real estate | 2022 |
| Klara Ascot Limited | Construction | 2020 |
| Klara Barnet Limited | Construction | 2020 |
| Klara Berk Limited | Construction | 2020 |
| Klara Homes Limited | Construction | 2019 |
| Klara Hughes Holdings Ltd | Construction | 2024 |
| Klara Pilgrim Investments Ltd | Real estate | 2025 |
| Klara Pilgrim Ltd | Construction | 2024 |
| Klara Squire Investments Limited | Real estate | 2022 |
| Klara Squire Limited | Construction | 2021 |
| Klara Victoria Ltd | Construction | 2020 |
| KLT Promotions Limited | Arts & recreation | 2015 |
| Klunkie Ltd | Hospitality | 2015 |
| KM Eco Ltd | Water & waste | 2018 |
| KM Eco Solutions Limited | Professional & scientific | 2014 |
| KM400 Ltd | Financial services | 2021 |
| KM4GROUP Ltd | Administrative & support | 2026 |
| Kmpm Limited | Construction | 2017 |
| Kneading Pizza Ltd | Hospitality | 2022 |
| Knight & Sugar Co. Limited | Hospitality | 2025 |
| Knight P M L Limited | Real estate | 2008 |
| Knighthood Financial Advisers Ltd | Financial services | 2014 |
| Koala ARB Limited | Administrative & support | 2021 |
| Kon-Tiki Marine Limited | Administrative & support | 2010 |
| Konstrukt Ltd | Construction | 2023 |
| Kontiki Shipbrokers Ltd. | Administrative & support | 2011 |
| Kontiki Valuations Limited | Wholesale & retail | 2010 |
| Kopi Coffee Ltd | Hospitality | 2025 |
| Koretz Limited | Real estate | 2025 |
| Korona Direct Ltd | Construction | 2014 |
| KP Consultancy and Design Limited | Professional & scientific | 2006 |
| KP Financial Consulting Ltd | Professional & scientific | 2024 |
| Kpbb Limited | Administrative & support | 2019 |
| Krdb Investments Ltd | Other services | 2013 |
| Krila Ltd | Health & social care | 2019 |
| KRIS2020 Ltd | Transport & logistics | 2022 |
| Ksbr Brand Futures Holdings Ltd | Professional & scientific | 2026 |
| Ksbr Brand Futures Limited | Professional & scientific | 2004 |
| KT Copy Limited | Information & communication | 2010 |
| KTG Lymphatic Clinic Ltd | Other services | 2024 |
| Kurled Global Limited | Wholesale & retail | 2024 |
| KUT Energy Limited | Administrative & support | 2009 |
| KUT Land Limited | Real estate | 2006 |
| Kuzi Heath Care Limited | Health & social care | 2024 |