| Jb&Hv Medics Ltd | Health & social care | 2021 |
| Jbjk Investments Ltd | Real estate | 2017 |
| JD Eco House Ltd | Construction | 2018 |
| Jdel Construction Ltd | Manufacturing | 2018 |
| Jdonoghue Structural Design Limited | Professional & scientific | 2015 |
| JE Advisory Ltd | Professional & scientific | 2021 |
| Jess and the Beanstalk Ltd | Manufacturing | 2018 |
| Jetopa Ltd | Real estate | 2020 |
| Jeva Films Limited | Information & communication | 2006 |
| Jgc-Surveys Ltd | Professional & scientific | 2025 |
| Jillian Close Limited | Real estate | 2014 |
| JIN & TAN Limited | Real estate | 2015 |
| Jjak Property Investing Ltd | Real estate | 2019 |
| JJK Property Ltd | Construction | 2015 |
| JL Investment Holdings Ltd | Real estate | 2019 |
| JLV Contracts Ltd. | Information & communication | 2016 |
| JLW Property Investments Ltd | Real estate | 2016 |
| JMC Mechanical Advisor Ltd | Professional & scientific | 2014 |
| JMD Capital Limited | Construction | 2021 |
| JMD Capital Management Limited | Construction | 2021 |
| Jobladder Limited | Professional & scientific | 2003 |
| JOE Winders Electrical Ltd | Construction | 2023 |
| John Dollimore Limited | Manufacturing | 2007 |
| John Hofer Limited | Agriculture & fishing | 1974 |
| Jopling Associates Limited | Administrative & support | 2007 |
| Joseph Allen Carpentry Ltd | Manufacturing | 2022 |
| JP & KT Ltd | Other services | 2018 |
| Jptr Ltd | Arts & recreation | 2016 |
| JRR Electrical Contractors Ltd | Construction | 2021 |
| Jules Plumbing Heating & Electrical Services Ltd | Construction | 2012 |
| Julien Siyuan C Property Ltd | Extraterritorial | 2019 |
| Junior Darts Limited | Arts & recreation | 2017 |
| Jusjansun Ltd | Real estate | 2018 |
| Just Good Frames Limited | Manufacturing | 2018 |
| JUSTECU4U Ltd | Wholesale & retail | 2020 |
| JW Landscapes Limited | Administrative & support | 2023 |
| Jwbrew Limited | Hospitality | 2016 |
| JWP Recruitment Limited | Administrative & support | 2021 |
| JXR Capital Ltd | Financial services | 2026 |
| K Amor Investments Ltd | Real estate | 2017 |
| K&Co Services Ltd | Administrative & support | 2021 |
| K&M Media Ltd | Information & communication | 2017 |
| K.A Chauffeur on Call Ltd | Transport & logistics | 2025 |
| Kadar Constructions Ltd | Construction | 2013 |
| Kadema Ltd | Public administration | 2025 |
| Kahvi Limited | Wholesale & retail | 2015 |
| Kaleidoscope Music Management & Publishing Limited | Information & communication | 1998 |
| Kalm Tech Ltd | Information & communication | 2010 |
| Kamal Properties & Investments Ltd | Real estate | 2018 |
| Kammy Tech Limited | Information & communication | 2012 |
| Kandyans Ltd | Extraterritorial | 2017 |
| Kanniedood Productions Ltd | Transport & logistics | 2023 |
| Karrot Entertainment Limited | Information & communication | 2002 |
| Karrotone Limited | Information & communication | 2021 |
| Kasawari Limited | Extraterritorial | 2014 |
| Kasha Events Ltd | Wholesale & retail | 2025 |
| Kassa Properties Ltd | Real estate | 2016 |
| Kaymo Holdings Limited | Financial services | 2025 |
| KEA 2014 Ltd | Wholesale & retail | 2014 |
| Kellkevs Limited | Information & communication | 2014 |
| Kelvadon Computer Services Limited | Wholesale & retail | 1983 |
| Kermack Consulting Limited | Administrative & support | 2014 |
| Kesego Ltd | Wholesale & retail | 2023 |
| Key 3 Films Limited | Information & communication | 2022 |
| Kidztough Ltd | Administrative & support | 2017 |
| Kieftproperties Ltd | Extraterritorial | 2020 |
| Kiely Holdings Limited | Professional & scientific | 2004 |
| Kiely Investments Limited | Professional & scientific | 1972 |
| Kiely Properties Limited | Households | 1996 |
| Kilinc Investment and Real Estate Ltd | Real estate | 2018 |
| KIM Curran Ltd. | Information & communication | 2008 |
| KIM Software Trustees Limited | Information & communication | 2022 |
| Kimber Educational Consultancy Ltd | Education | 2026 |
| Kimpton's Cleaning Limited | Administrative & support | 2024 |
| Kinesys Projects Limited | Manufacturing | 2002 |
| Kinetic Cars Limited | Wholesale & retail | 2011 |
| Kinetic Concepts Ltd | Financial services | 2019 |
| Kingsbury Coachworks Ltd | Wholesale & retail | 2025 |
| Kingsley Court Hampton Management Limited | Households | 2023 |
| Kinnelhead Ltd | Information & communication | 2023 |
| Kish Kindergarten Ltd | Administrative & support | 2009 |
| Kiwi IT Consulting Limited | Professional & scientific | 2022 |
| Kk.Yiu Properties Ltd | Real estate | 2018 |
| KL Home Improvement Limited | Construction | 2025 |
| Klimchi Ltd | Wholesale & retail | 2020 |
| KLO Live Ltd | Arts & recreation | 2021 |
| KLO Music Ltd | Information & communication | 2021 |
| Knightsbridge & General Investments Limited | Real estate | 1980 |
| Knocknarea Civils Ltd | Construction | 2014 |
| Knockout Design Limited | Other services | 2017 |
| Knowledge Music Publishing Ltd | Information & communication | 2021 |
| Knowledgeable Ltd. | Professional & scientific | 2005 |
| KNP Investment Limited | Real estate | 2018 |
| Kodram Limited | Construction | 2015 |
| Korean Ltd | Hospitality | 2020 |
| Korean Veterans Association UK CIC | Health & social care | 2025 |
| Kovan Investment Properties Ltd | Real estate | 2016 |
| Kowhai Financial Services Limited | Professional & scientific | 2026 |
| Kranston Investments Ltd | Real estate | 2025 |
| Kranthews Ltd | Information & communication | 2022 |