| Kayleigh Toyra Ltd | Professional & scientific | 2022 |
| Kayna HNA Ltd | Information & communication | 2025 |
| Kaynaan Technology Ltd | Information & communication | 2018 |
| Kaysandy Ejgthc Ltd | Health & social care | 2022 |
| Kayti Jackson Engineering Ltd | Professional & scientific | 2024 |
| KAZ (Cardiff) Ltd | Hospitality | 2018 |
| KAZ 17 Limited | Health & social care | 2017 |
| KAZ Catering Limited | Hospitality | 2008 |
| Kazcert Limited | Administrative & support | 2017 |
| Kazi Traders Ltd | Wholesale & retail | 2020 |
| Kazifx Ltd | Professional & scientific | 2019 |
| Kazim Mart Ltd | Wholesale & retail | 2026 |
| Kazimin Limited | Wholesale & retail | 2023 |
| Kazipur Ltd | Financial services | 2025 |
| Kazo Consulting Limited | Professional & scientific | 2024 |
| Kazzacus Limited | Wholesale & retail | 2021 |
| KB Building Solutions Ltd | Construction | 2019 |
| KB Classics Ltd | Manufacturing | 2019 |
| KB Facilities Ltd | Water & waste | 2026 |
| KB GAS Plumber Heating Engineers Ltd | Other services | 2014 |
| KB Media Limited | Construction | 2022 |
| KBB Momentum Ltd | Professional & scientific | 2025 |
| KBD Services Ltd | Health & social care | 2019 |
| KBJ Worldwide Music Ltd | Information & communication | 2020 |
| KBL Group Limited | Financial services | 2021 |
| KC ATS Ltd | Professional & scientific | 2025 |
| KC Construction and Development Ltd | Construction | 2012 |
| KC Seven Holdings Ltd | Financial services | 2022 |
| Kcarsdunde Ltd | Wholesale & retail | 2025 |
| Kcbro Ltd | Hospitality | 2026 |
| KCC Nominee 1 (P1 Resi) Limited | Construction | 2011 |
| KCC Nominee 1 (T1 Resi) Limited | Construction | 2012 |
| KCC Nominee 2 (T1 Resi) Limited | Construction | 2012 |
| KCC T/A Kulocar.Com Limited | Transport & logistics | 2018 |
| KCC Yacht Limited | Extraterritorial | 2018 |
| KCF Cardiff Limited | Hospitality | 2024 |
| Kchsncxccv Ltd | Wholesale & retail | 2023 |
| KCJ Engineering Limited | Manufacturing | 2002 |
| Kconer Ltd | Wholesale & retail | 2026 |
| Kctsxpm Mart Ltd | Wholesale & retail | 2025 |
| KD Property Management Ltd | Real estate | 2020 |
| KD Web Consultancy Services Ltd | Information & communication | 2019 |
| Kdesigns Creation & Decor Ltd | Hospitality | 2021 |
| KDG Consulting Ltd | Professional & scientific | 2025 |
| Kdirn Ltd | Wholesale & retail | 2025 |
| KDL Global Limited | Real estate | 2024 |
| KDM Couriers Plus Limited | Transport & logistics | 2013 |
| KDM Highways Ltd | Administrative & support | 2020 |
| KDT Management Limited | Professional & scientific | 2009 |
| KE Liang Ltd | Professional & scientific | 2025 |
| KEA Trading Ltd | Transport & logistics | 2022 |
| KEA Travels Ltd | Transport & logistics | 2026 |
| Kear Goodger Ltd | Construction | 2026 |
| Kear Property Group Limited | Real estate | 2019 |
| Keast Group Ltd | Wholesale & retail | 2022 |
| Keates & Co LLP | | 2013 |
| Keay Refurbs Ltd | Construction | 2018 |
| Kebab King CF5 Ltd | Hospitality | 2022 |
| Kebab Slemany Ltd | Hospitality | 2025 |
| Kebabish Grill House Ltd | Hospitality | 2019 |
| Kebulan Limited | Wholesale & retail | 2019 |
| Kedaf Limited | Professional & scientific | 2014 |
| Kedleston Windows & Doors Limited | Manufacturing | 2019 |
| Keelson Ltd | Construction | 2013 |
| Keemhaus Solutions Ltd | Information & communication | 2026 |
| Keen World Co., Limited | Wholesale & retail | 2020 |
| Keep Children Safe Online CIC | Education | 2014 |
| Keep Security Solutions Ltd | Administrative & support | 2017 |
| Keep Trade Limited | Wholesale & retail | 2025 |
| Keep Wales Tidy | Other services | 2000 |
| Keepfaith Ltd | Wholesale & retail | 2025 |
| Keepfer Flooring Agencies Ltd | Construction | 2014 |
| Keeping IT Limited | Information & communication | 2017 |
| Keepsakeqr Ltd | Wholesale & retail | 2025 |
| Keetew Property Limited | Real estate | 2017 |
| Kefalas & Co Ltd | Professional & scientific | 2018 |
| Keferdiz Trade Ltd | Extraterritorial | 2022 |
| Kefteo Recruits Ltd | Wholesale & retail | 2021 |
| KEG Belly Limited | Hospitality | 2023 |
| Kegbelly II Limited | Hospitality | 2026 |
| KEH Group Limited | Professional & scientific | 2018 |
| Kehinde B Limited | Professional & scientific | 2018 |
| Kehun Ltd | Wholesale & retail | 2024 |
| Keima Limited | Information & communication | 2006 |
| Keith Edwards Limited | Professional & scientific | 2014 |
| Keith Wakley Associates Limited | Professional & scientific | 2005 |
| Keizer PC | | 2014 |
| Kejife Ltd | Manufacturing | 2026 |
| Keke Tutu Co., Ltd | Information & communication | 2021 |
| KEL Medical Consulting Limited | Health & social care | 2024 |
| Keller Kitchens Limited | Wholesale & retail | 2003 |
| Kellerhvac Ltd | Construction | 2026 |
| Kelliy Limited | Wholesale & retail | 2021 |
| Kelly and Leigh Holistic Health Limited | Health & social care | 2023 |
| Kelly Lalor | | 2007 |
| Kelly Property Holdings Ltd | Real estate | 2022 |
| Kellycat PC | | 2017 |
| Kellymatics Ltd | Information & communication | 2015 |
| Kellys Estates Limited | Real estate | 2021 |
| Kelo Properties Limited | Real estate | 2026 |