| K D Fine Art Limited | Administrative & support | 1997 |
| K Lineage Ltd | Real estate | 2021 |
| K Mitchell Ltd | Construction | 2013 |
| K S Aesthetiks Limited | Health & social care | 2021 |
| K S T Therapy Ltd | Arts & recreation | 2021 |
| K. O. Premier Training & Assessment Limited | Education | 2006 |
| K.B. Coaching Limited | Arts & recreation | 2002 |
| K2 Corporate Mobility Limited | Administrative & support | 2002 |
| K21I Limited | Financial services | 2021 |
| K9 Life Limited | Other services | 2023 |
| K9 Limited | Financial services | 1998 |
| K98 Ltd | Administrative & support | 2024 |
| K9S Dog Walking Ltd | Other services | 2024 |
| KAB Property Ltd | Real estate | 2022 |
| Kabenge Aero Solutions Ltd | Transport & logistics | 2024 |
| Kabu Films Limited | Information & communication | 2021 |
| Kabuki Communications Limited | Information & communication | 2007 |
| Kadosh Legal Ltd | Professional & scientific | 2019 |
| Kaexchange Limited | Financial services | 2025 |
| Kagger PM Ltd | Professional & scientific | 2012 |
| Kaico Limited | Hospitality | 2025 |
| Kaios Media Limited | Information & communication | 2025 |
| Kairos Economic Consulting Limited | Professional & scientific | 2023 |
| Kaisa Technologies Ltd | Information & communication | 2013 |
| Kaiserdore Games Ltd | Information & communication | 2026 |
| Kaizen IO Ltd | Information & communication | 2024 |
| KAL Capital Partners Limited | Financial services | 2016 |
| Kalaya Ltd | Real estate | 2020 |
| Kalis Limited | Hospitality | 2008 |
| Kallie’S Deli Ltd | Hospitality | 2020 |
| Kallos Esti Ltd | Manufacturing | 2025 |
| Kalm Club Ltd | Extraterritorial | 2026 |
| Kalm Property Holdings Ltd | Real estate | 2024 |
| Kamp South Ltd | Information & communication | 2026 |
| Kanvas Events Ltd | Professional & scientific | 2023 |
| Kaon Limited | Professional & scientific | 1994 |
| Kara 68 Limited | Hospitality | 2024 |
| Karate for Mental Health CIC | Education | 2024 |
| Karen Jewell Ltd | Professional & scientific | 2002 |
| Karen Oliver - Coaching Conversations Limited | Professional & scientific | 2022 |
| Karina Fernandez Limited | Information & communication | 2013 |
| Karis Smart Cleaning Services Ltd | Administrative & support | 2024 |
| Karl Derrick Limited | Arts & recreation | 2006 |
| Karoo Kapitaal Limited | Professional & scientific | 2023 |
| Karumba Consulting Limited | Information & communication | 2014 |
| Kasa Source Build Ltd | Construction | 2017 |
| Kasa Source IT Ltd | Information & communication | 2017 |
| Kasorb Limited | Information & communication | 2024 |
| Kasvama Limited | Professional & scientific | 2019 |
| Kata Care Ltd | Health & social care | 2025 |
| Katana Partners Ltd | Professional & scientific | 2024 |
| Katherine Bruce Mental Health Consulting Ltd | Health & social care | 2022 |
| Kathleen House Ltd | Households | 2020 |
| Katy Nails Ltd | Other services | 2026 |
| Kaye Enterprises Limited | Professional & scientific | 1989 |
| Kayz Solutions Ltd | Health & social care | 2024 |
| KB Property Invest Ltd | Real estate | 2024 |
| KB South Way Ltd | Other services | 2022 |
| Kbiosciences Limited | Professional & scientific | 2002 |
| Kbun | Financial services | 2020 |
| Kcmatech Ltd | Information & communication | 2020 |
| KD Landscapes Ltd | Administrative & support | 2010 |
| KDL Horizons Ltd. | Financial services | 2026 |
| Keda 2002 Services Ltd | Water & waste | 2018 |
| Keelans Ltd | Real estate | 2012 |
| Kefi Investments Limited | Real estate | 2021 |
| Keith Johnson Consulting Limited | Financial services | 1998 |
| Keithfd Ltd | Professional & scientific | 2024 |
| Kelly Barlow Consulting Ltd | Professional & scientific | 2019 |
| Kelly Howie Aesthetics Ltd | Health & social care | 2026 |
| Kelly Mortimer Limited | Professional & scientific | 2018 |
| Kelly's Developments Limited | Construction | 2014 |
| Kelly's International Limited | Transport & logistics | 1986 |
| Kelly's Removals & Transport (Guildford) Limited | Transport & logistics | 1958 |
| Kelly's Sccs Limited | Professional & scientific | 2024 |
| Kelly's Storage Limited | Information & communication | 1999 |
| Kellys Self Storage Limited | Administrative & support | 2008 |
| Kelz Group Ltd | Wholesale & retail | 2021 |
| Kemet Oncology Ltd | Health & social care | 2025 |
| Kenadsa Ltd | Information & communication | 2026 |
| Kendale Court Management Company Limited | Households | 2014 |
| Kendall Cars Limited | Administrative & support | 1987 |
| Kennet Heath Management (NO.3) Limited | Extraterritorial | 2005 |
| Kenney Sports Limited | Arts & recreation | 2015 |
| Kent (United Kingdom) Ltd | Wholesale & retail | 2012 |
| Kentico Software Limited | Information & communication | 2011 |
| Kenton Advisory Ltd | Professional & scientific | 2025 |
| Kenwa Consulting Ltd | Professional & scientific | 2024 |
| Kenz AZM UK Limited | Administrative & support | 2016 |
| Kerrera Bar Limited | Hospitality | 2022 |
| Kerwave Ltd | Information & communication | 2025 |
| Kestrel Group Ltd | Financial services | 2026 |
| Kestrel Manufacturing Ltd | Manufacturing | 2026 |
| Ketax Limited | Professional & scientific | 2001 |
| Key Properties (Surrey) Limited | Real estate | 2002 |
| Keymat Technology Limited | Manufacturing | 1986 |
| Keyway Property Ltd | Real estate | 2016 |
| Kezia Cook Ltd | Other services | 2022 |
| KG Premium Ltd | Real estate | 2026 |
| KGC Autocare Limited | Wholesale & retail | 2003 |