| Kinetic Podiatry Clinic Limited | Other services | 2014 |
| King & Webb (England) Limited | Extraterritorial | 2021 |
| Kingfisher Prestige Developments Limited | Construction | 2001 |
| Kings Eight Management Limited | Real estate | 1999 |
| Kingsley Construction Management Limited | Construction | 1999 |
| Kingsley Management Ltd | Construction | 2025 |
| Kingsmere Estate Management Limited | Households | 2018 |
| Kinky INK Limited | Other services | 2014 |
| KIP Mcgrath Beaulieu Limited | Education | 2016 |
| Kira Developments Limited | Information & communication | 1997 |
| Kirchweidli LLP | | 2013 |
| Kirrane Limited | Information & communication | 2001 |
| Kisheeya Limited | Health & social care | 2024 |
| Kiss London Limited | Other services | 2018 |
| Kitchen 59 Limited | Hospitality | 2025 |
| Kitchen Surveys Ltd | Professional & scientific | 2024 |
| Kitchencentro Limited | Construction | 2009 |
| KJC Group Ltd | Financial services | 2026 |
| KJO Consultants Limited | Financial services | 2003 |
| KL Hire Services Limited | Administrative & support | 2011 |
| KL10 Ltd | Administrative & support | 2024 |
| Klaudworks Limited | Information & communication | 2018 |
| Klaus Ltd | Information & communication | 2006 |
| KLB Recruitment Services Ltd | Administrative & support | 2018 |
| Kliklocal Ltd | Administrative & support | 2014 |
| KLM Securities London Limited | Financial services | 2022 |
| KMB Construction Services Limited | Construction | 2024 |
| KMD Group Limited | Professional & scientific | 2017 |
| KMD Private Office Limited | Professional & scientific | 2012 |
| KMG Homes Ltd | Real estate | 2018 |
| KMG Properties Ltd | Real estate | 2015 |
| KMG Property Group Limited | Real estate | 2021 |
| KMM2306 Ltd. | Construction | 1981 |
| KMP FIX Limited | Construction | 2024 |
| KMS Compliance Ltd | Professional & scientific | 2026 |
| Knight Court Developments Limited | Construction | 2014 |
| Knight Court II Developments Limited | Construction | 2018 |
| KO Accountancy Ltd | Professional & scientific | 2026 |
| KO Franchise Limited | Hospitality | 2014 |
| Korpeet Ltd | Extraterritorial | 2010 |
| Koru Educational Services Ltd | Administrative & support | 2017 |
| Koybus Limited | Wholesale & retail | 2005 |
| KPA Consulting Limited | Professional & scientific | 2017 |
| Kpfm Ltd | Administrative & support | 2020 |
| Kreed Lift Services Limited | Construction | 2026 |
| KRI Skincare Ltd | Wholesale & retail | 2016 |
| KRI Studio Ltd | Professional & scientific | 2024 |
| Kristina Mack Studios Limited | Professional & scientific | 2019 |
| Kristine Monaghan Ltd | Professional & scientific | 2022 |
| Krux Consulting Limited | Wholesale & retail | 2015 |
| KS Motors London Ltd | Wholesale & retail | 2020 |
| KS Plant and Marine Ltd | Wholesale & retail | 2013 |
| KS Vision Services Ltd | Administrative & support | 2015 |
| KT Becks Limited | Real estate | 2020 |
| KT Renovations (Surrey) Ltd | Construction | 2023 |
| KTS Global Limited | Administrative & support | 2014 |
| KTS Group Limited | Real estate | 1991 |
| KTS London Limited | Other services | 2016 |
| KTS Properties Limited | Administrative & support | 2014 |
| KTS Residential Limited | Real estate | 2026 |
| Ktse Ltd | Transport & logistics | 2009 |
| KTW Solutions Ltd | Professional & scientific | 2010 |
| KTZ Trade Ltd | Wholesale & retail | 2016 |
| Kujama Limited | Information & communication | 2000 |
| Kumiho Solutions Limited | Construction | 2014 |
| Kustom Adventure Vehicles Limited | Wholesale & retail | 2022 |
| Kvplumbing Limited | Construction | 2025 |
| KWC Services Limited | Health & social care | 2024 |
| Kyber Ltd | Other services | 2018 |
| Kylton Design Limited | Professional & scientific | 2020 |
| KYM Spa Ltd | Other services | 2025 |
| L & J Fashion Ltd | Wholesale & retail | 2012 |
| L & K Floral Design Ltd | Wholesale & retail | 2019 |
| L & W Site Services Ltd | Professional & scientific | 2015 |
| L a Security & Traffic Ltd | Administrative & support | 2011 |
| L H Cook Plumbing & Heating Limited | Construction | 2008 |
| L J Drain Limited | Other services | 1998 |
| L K Taxi Rentals Ltd | Transport & logistics | 2019 |
| L Mallon Ltd | Administrative & support | 2022 |
| L V Repairs Limited | Wholesale & retail | 2017 |
| L&C Developments Ltd | Construction | 2024 |
| L&V Associates Limited | Professional & scientific | 2020 |
| L&W Professional Cleaning Limited | Administrative & support | 2019 |
| L'Art by DR M Ltd | Health & social care | 2016 |
| L.G.M. Builds Ltd | Construction | 2018 |
| LA Construction Limited | Construction | 1997 |
| LA Farina Ltd | Hospitality | 2020 |
| LA Laser Ltd | Wholesale & retail | 2018 |
| LA Maison DE Rayson Limited | Manufacturing | 2017 |
| LA MIA Italia Ltd | Wholesale & retail | 2011 |
| LA Piazzetta Restaurant Limited | Hospitality | 2018 |
| LA Vita Organic Limited | Wholesale & retail | 2023 |
| Laaj Property Services Limited | Real estate | 2025 |
| Label Likes Limited | Information & communication | 2026 |
| Labelcode Ltd | Administrative & support | 2019 |
| Laboratory Designs Ltd | Manufacturing | 2013 |
| Lacer Limited | Construction | 2013 |
| Lacuna Edge Ltd | Information & communication | 2017 |
| Laddery Limited | Information & communication | 2020 |
| Ladj Property Investments Ltd | Real estate | 2020 |