| KLJ & Sons Limited | Professional & scientific | 2014 |
| KLK Holdings Ltd | Real estate | 2025 |
| KLM Auto Repairs Ltd | Wholesale & retail | 2019 |
| KLM Heating & Plumbing (Bedford) Ltd | Construction | 2021 |
| KLN Group Ltd | Construction | 2015 |
| KM Blooms and Events Ltd | Wholesale & retail | 2021 |
| KMF Electrics Limited | Construction | 2003 |
| KMN Enterprise Ltd | Manufacturing | 2020 |
| Kmpo Pharma Ltd | Health & social care | 2026 |
| KMS Transport Limited | Transport & logistics | 2013 |
| KMW Property Services Limited | Construction | 2007 |
| KMW Sound Limited | Information & communication | 2014 |
| KN Technik Ltd | Wholesale & retail | 2024 |
| Knead for Change Ltd | Wholesale & retail | 2026 |
| Knelectrical Solutions Limited | Construction | 2026 |
| KNI Partners Ltd | Information & communication | 2024 |
| Knight Capital Limited | Real estate | 2019 |
| Knight Marine Design Ltd | Professional & scientific | 2013 |
| Knightley Property Investments Ltd | Real estate | 2020 |
| Knights Avenue and Duke Drive Clapham Property Company Limited | Hospitality | 2006 |
| Knights Sales Consultancy Limited | Professional & scientific | 2021 |
| KNN5 Ltd | Real estate | 2021 |
| Knocknagore Services Limited | Construction | 2018 |
| Know Your Tax (KYT) Limited | Professional & scientific | 2023 |
| Knowe Care Ability Limited | Health & social care | 2023 |
| Knox Access Ltd | Administrative & support | 2026 |
| Knox Aviation Trading Limited | Financial services | 2018 |
| Knpm Ltd | Health & social care | 2024 |
| KNR Electrics Ltd | Construction | 2014 |
| KO Cuts Ltd | Other services | 2018 |
| KO Decorating Limited | Construction | 2019 |
| Kodemotros Ltd | Information & communication | 2025 |
| Koko Holdings Limited | Financial services | 2025 |
| Kollision Games Limited | Information & communication | 2023 |
| Kombi Services Limited | Professional & scientific | 1992 |
| Kombo Care Ltd | Health & social care | 2014 |
| Kompass Consulting Limited | Professional & scientific | 2023 |
| Konin Ltd | Wholesale & retail | 2014 |
| Konzo Limited | Real estate | 2020 |
| Kool Tech Solutions Ltd | Information & communication | 2017 |
| Kopaonic Ltd | Construction | 2026 |
| Korgaonkar Medical Services Limited | Health & social care | 2017 |
| Korolit Global Ltd | Professional & scientific | 2017 |
| Koronax Limited | Manufacturing | 2021 |
| Korum Services Limited | Construction | 2017 |
| Koruu Consultants Limited | Professional & scientific | 2025 |
| Kosanah Ltd | Real estate | 2021 |
| Kotecha & Singh Property Ltd | Real estate | 2025 |
| Kottan Limited | Public administration | 2025 |
| Kowalska-Clements Limited | Real estate | 2023 |
| KP Asbestos Ltd | Construction | 2022 |
| KP Community Services Limited | Health & social care | 2025 |
| KP Field Services Limited | Administrative & support | 2023 |
| KPA Associates Limited | Professional & scientific | 2025 |
| KPB Homes Ltd | Real estate | 2020 |
| KPG Property Investment Group Ltd | Real estate | 2024 |
| KPI People Ltd | Administrative & support | 2013 |
| KPR Architects Ltd | Professional & scientific | 2020 |
| KPS Automotive Parts Limited | Wholesale & retail | 2004 |
| KR Cricket Academy Limited | Education | 2021 |
| KR Services Group Ltd | Construction | 2021 |
| Kraken MMA & Fitness Ltd | Arts & recreation | 2018 |
| Kraken MMA Ltd | Arts & recreation | 2022 |
| Kraken Plumbing & Heating Limited | Construction | 2019 |
| Kramhull Limited | Administrative & support | 2011 |
| Krause Bespoke Limited | Administrative & support | 2026 |
| KRB Property Limited | Real estate | 2012 |
| KRD Connect Ltd | Health & social care | 2024 |
| Krio Patois Ltd | Professional & scientific | 2023 |
| Krish Odedra Properties Ltd | Real estate | 2017 |
| Kristel Homes Limited | Real estate | 2019 |
| Krogers Administration Limited | Extraterritorial | 2007 |
| Krogers Investments Limited | Extraterritorial | 2007 |
| Krogers Services Limited | Extraterritorial | 2007 |
| Kronixx Ltd | Wholesale & retail | 2019 |
| KRP Music Ltd | Arts & recreation | 2025 |
| KRS FAB Limited | Manufacturing | 2009 |
| Krull Creation LP | | 2009 |
| Kruse People Solutions Limited | Professional & scientific | 2024 |
| KRW Braeside Property Limited | Real estate | 2024 |
| KRW Tech Ltd | Construction | 2018 |
| Krystian Martini Ltd | Wholesale & retail | 2018 |
| Krzysztof Chauffeur Ltd | Transport & logistics | 2024 |
| Krzysztof Sikora Limited | Wholesale & retail | 2015 |
| KS Associates Quantity Surveyors Limited | Administrative & support | 2005 |
| KS Care Ltd | Health & social care | 2016 |
| KS Connect Property Investment Ltd | Real estate | 2025 |
| KS Connect Property Management Ltd | Real estate | 2024 |
| KS Food Connection Ltd | Wholesale & retail | 2023 |
| KS Food Hub Ltd | Hospitality | 2024 |
| KS Retail Connect Ltd | Wholesale & retail | 2022 |
| KSA Green Solutions Ltd | Water & waste | 2025 |
| KSA Management Ltd | Real estate | 2021 |
| Ksblinks Ltd | Other services | 2023 |
| KSE Contractors Limited | Construction | 2023 |
| KSK Apartments Ltd | Real estate | 2021 |
| Ksmua Ltd | Arts & recreation | 2013 |
| Ksquarestech Ltd | Professional & scientific | 2026 |
| KSS Chiltern Properties Ltd | Real estate | 2018 |
| Kstsk Limited | Education | 2016 |