| Juno (Plant Protection) Limited | Agriculture & fishing | 2009 |
| JUNTOS19 Ltd | Transport & logistics | 2023 |
| Jupiter Developments Ltd | Construction | 2024 |
| JUS Glaze Ltd | Administrative & support | 2007 |
| Just Cables Electrical & Automation Limited | Construction | 2017 |
| Just Health Communications Ltd | Extraterritorial | 2006 |
| Just Heat Services Limited | Construction | 2017 |
| Just Mango Tree Limited | Hospitality | 2007 |
| Just Peachy Florist Limited | Wholesale & retail | 2020 |
| Just the 1 Ltd | Manufacturing | 2021 |
| Just Woke CUP Coffee Ltd | Wholesale & retail | 2025 |
| Justapshop Ltd | Wholesale & retail | 2025 |
| Justice Empire Ltd | Professional & scientific | 2010 |
| Justiming Limited | Administrative & support | 2011 |
| Justnaiah Ltd | Health & social care | 2025 |
| Juvenology Ltd | Health & social care | 2023 |
| JV Moss Holdings Limited | Financial services | 2021 |
| Jvhn Limited | Wholesale & retail | 2024 |
| JW Clough Gym & Playground Services Ltd | Professional & scientific | 2023 |
| Jwtn Ltd | Financial services | 2022 |
| K Barnes Electrical Services Limited | Construction | 2002 |
| K BAT Logistics Ltd | Transport & logistics | 2021 |
| K Design Consultancy LLP | | 2002 |
| K F C (Flooring) Limited | Administrative & support | 2015 |
| K K L & Co. Ltd | Hospitality | 2013 |
| K K Smith Services Limited | Construction | 2015 |
| K Lacey Limited | Wholesale & retail | 2022 |
| K M Portfolios Limited | Administrative & support | 2006 |
| K P Architectural Services Ltd | Professional & scientific | 2015 |
| K S Y Motors Ltd | Wholesale & retail | 2017 |
| K Smith Mobile Mechanic Ltd | Wholesale & retail | 2020 |
| K Sports Trading Limited | Wholesale & retail | 2017 |
| K T Carpentry & Construction Limited | Construction | 2012 |
| K T J Mobile Service Company Ltd | Wholesale & retail | 2015 |
| K&A Barber Limited | Other services | 2019 |
| K&A Traders Limited | Wholesale & retail | 2024 |
| K&B Recruitment Ltd | Administrative & support | 2024 |
| K&C Civils Ltd | Construction | 2020 |
| K&D Building & Refurbishment Ltd | Construction | 2026 |
| K&L Mccabe Ltd | Financial services | 2024 |
| K&Mc Transport Ltd | Transport & logistics | 2024 |
| K&S Properties Investments Limited | Real estate | 2025 |
| K-Build Contractors Ltd | Construction | 2026 |
| K. Sung Limited | Manufacturing | 2014 |
| K.C. Enterprises (Kent) Limited | Construction | 2001 |
| K.K.& Toshev Solutions Ltd | Administrative & support | 2026 |
| K.L.R.Marketing Services Limited | Information & communication | 2004 |
| K.M.C Construction (London) Limited | Construction | 2012 |
| K.Ofori-Atta Healthcare Ltd | Health & social care | 2019 |
| K.Ssidor. Ltd | Administrative & support | 2016 |
| K2 Mobiles Ltd | Wholesale & retail | 2020 |
| K2 Smiles Ltd | Health & social care | 2014 |
| K20 Motors Limited | Wholesale & retail | 2020 |
| K2O Creative Ltd | Professional & scientific | 2022 |
| K4 Care Bedford Limited | Health & social care | 2015 |
| K4FLT Training UK Limited | Professional & scientific | 2007 |
| K4Z Ltd | Health & social care | 2019 |
| K9 Academy Limited | Professional & scientific | 2018 |
| K9 Crew Events Ltd | Wholesale & retail | 2018 |
| K9 Plumbing Supplies Limited | Wholesale & retail | 2022 |
| KA2 Limited | Information & communication | 2017 |
| Kaabaa Ltd | Information & communication | 2023 |
| Kabelbaum Techniq Ltd | Wholesale & retail | 2026 |
| Kabn Company Holdings Ltd | Financial services | 2019 |
| Kabn Management Limited | Construction | 2025 |
| Kabn One Limited | Hospitality | 2019 |
| Kabn Special Projects Limited | Construction | 2025 |
| Kabys Delight Limited | Hospitality | 2025 |
| Kadamala Limited | Health & social care | 2023 |
| Kade JL Limited | Real estate | 2020 |
| Kadolite Limited | Professional & scientific | 2016 |
| Kaffee Culture Ltd | Hospitality | 2019 |
| Kaftan Luxe Limited | Wholesale & retail | 2025 |
| Kahlon Nedelea Properties Limited | Real estate | 2022 |
| Kahlon Property Investment Ltd | Real estate | 2022 |
| KAI VV Homes Ltd | Real estate | 2025 |
| Kailin Commodities Limited | Professional & scientific | 2023 |
| Kailin Limited | Professional & scientific | 2023 |
| Kairos Recruitment Limited | Administrative & support | 2005 |
| Kaishilp Limited | Wholesale & retail | 2024 |
| Kaituna Services Limited | Professional & scientific | 2007 |
| Kaizen Motorsport and Aviation Limited | Administrative & support | 2009 |
| Kaizen PMG Limited | Professional & scientific | 2018 |
| Kalibarber Ltd | Other services | 2026 |
| Kalinchev Logistics Limited | Transport & logistics | 2026 |
| Kallo Finance Ltd | Financial services | 2018 |
| Kallo Property Management Ltd | Real estate | 2025 |
| Kalo Trans Ltd | Transport & logistics | 2021 |
| Kamro Limited | Administrative & support | 2016 |
| Kamz Barber Limited | Other services | 2013 |
| Kandagoldstein Ltd | Administrative & support | 2022 |
| Kandawala Fabrics Ltd | Wholesale & retail | 2025 |
| Kaneera Stanwick Property Ltd | Wholesale & retail | 2026 |
| Kantos Group Limited | Professional & scientific | 2019 |
| KAO Trading Limited | Wholesale & retail | 2015 |
| KAR Health & Safety Consulting Ltd | Other services | 2022 |
| Karabas Limited | Transport & logistics | 2020 |
| KARAGYOZOV90 Ltd | Transport & logistics | 2019 |
| Karakus BR Limited | Hospitality | 2019 |
| Karen Dawkins Online Ltd | Administrative & support | 2021 |