| KD Private Limited | Wholesale & retail | 2021 |
| KD Tuning Ltd | Manufacturing | 2016 |
| KDE Systems Ltd | Information & communication | 2015 |
| KDO Developments Ltd | Extraterritorial | 2012 |
| KE & RJ Limited | Construction | 2019 |
| KE Medical Limited | Health & social care | 2023 |
| Kebabesh Limited | Hospitality | 2025 |
| Keeble Whelan Integrated Construction (Kwic) Limited | Construction | 2016 |
| Keeco Wellbeing LLP | | 2016 |
| Keel Over Limited | Extraterritorial | 2011 |
| Keen Equity Limited | Extraterritorial | 2003 |
| Keenoffer Limited | Real estate | 2009 |
| Keep Driving Auto Limited | Wholesale & retail | 2014 |
| Keep IT Klean Ltd | Administrative & support | 2016 |
| Keepmewell Ltd | Information & communication | 2018 |
| Keha Ltd | Real estate | 2018 |
| Keicam Properties Ltd | Real estate | 2024 |
| Keira Cares & Cleans Ltd | Administrative & support | 2026 |
| Keith B Ferguson Limited | Professional & scientific | 2003 |
| Keiya Solutions Ltd | Construction | 2017 |
| Kelcor Group Ltd | Financial services | 2023 |
| Kelden Fire & Security Solutions Ltd | Administrative & support | 2009 |
| Kelleher Property Ltd | Real estate | 2024 |
| Kelly & Nesbit Property Rentals Ltd | Real estate | 2025 |
| Kelly Cornwell Limited | Other services | 2006 |
| Kelly Harris Aesthetics Ltd | Other services | 2020 |
| Kelly Harris Holdings Limited | Financial services | 2026 |
| Kelly Rees Designs & Evants Ltd | Professional & scientific | 2025 |
| Kelly's Lettings & Rentals Ltd | Real estate | 2025 |
| Kelona Ltd | Health & social care | 2023 |
| Keltech Fire & Security Ltd | Administrative & support | 2026 |
| Kelvin E Donne Consulting Ltd | Professional & scientific | 2016 |
| KEN Mcinnes Limited | Construction | 2003 |
| KEN Williams Holdings Ltd | Professional & scientific | 2020 |
| KEN Williams Motors Ltd | Wholesale & retail | 2012 |
| Kenaz Development Ltd | Information & communication | 2024 |
| Kendall Services Ltd | Information & communication | 2023 |
| Kenealy Industrial Cleaning Specialist Limited | Administrative & support | 2021 |
| Kenfield (Swansea) Limited | Health & social care | 2003 |
| Kenfit Health Limited | Health & social care | 2023 |
| Kennexstone Leisure Limited | Hospitality | 2004 |
| Kerajo BFT Ltd | Financial services | 2020 |
| Kerajo Consulting Ltd | Professional & scientific | 2024 |
| Kerligan Consultants Limited | Other services | 2017 |
| Kershaw Connect Ltd | Construction | 2019 |
| Kesee Limited | Wholesale & retail | 2012 |
| Keston Property Services Limited | Real estate | 2014 |
| Kestral Construction (Albany Road) Limited | Construction | 2023 |
| Kestral Construction Holton Road Ltd | Construction | 2022 |
| Kevin Barron Limited | Transport & logistics | 2003 |
| Kevin Evans Building Services Limited | Administrative & support | 2024 |
| Kevin James Smith Wealth Managers LLP | | 2017 |
| Key Consult Ltd | Professional & scientific | 2013 |
| Key F2B Consulting Ltd | Professional & scientific | 2014 |
| Key Home Developments Ltd | Construction | 2021 |
| Key Properties UK1 Ltd | Real estate | 2025 |
| Key Property Lets Ltd | Real estate | 2017 |
| Key Surgery Limited | Health & social care | 2015 |
| Keycare Property Ltd | Real estate | 2016 |
| Keychanges - Unlocking Womens Potential | Education | 2011 |
| Keycymru CIC | Administrative & support | 2019 |
| Keyframe Ltd | Information & communication | 1998 |
| Keyhold Ventures Ltd | Construction | 2024 |
| Keyhope | Health & social care | 2004 |
| KG Carpentry and Building Limited | Construction | 2021 |
| KG Inspired Holdings Ltd | Real estate | 2022 |
| KG Inspired Kids Ltd | Real estate | 2021 |
| KG Inspired Management Ltd | Real estate | 2018 |
| KG Inspired Property Ltd | Financial services | 2019 |
| KG Inspired SA Ltd | Real estate | 2018 |
| KG Inspired Sourcing Ltd | Professional & scientific | 2019 |
| Kg's Cafe Limited | Hospitality | 2024 |
| Kg's Fish and Chips Ltd | Hospitality | 2023 |
| Kgroup Ltd | Construction | 2025 |
| Khan Dental Care Limited | Real estate | 2015 |
| Khan VEG Limited | Wholesale & retail | 2016 |
| Khaya Properties Limited | Real estate | 2017 |
| Khcy Limited | Wholesale & retail | 2019 |
| KHL (Gower) Limited | Hospitality | 2006 |
| Khryzaliz Ltd | Information & communication | 2024 |
| Khyam ALI Suleman Ltd | Other services | 2023 |
| KI6G Shawrama Ltd | Hospitality | 2023 |
| Kian Wholesale Ltd | Wholesale & retail | 2022 |
| Kibly’S Cleaning Solution Limited | Administrative & support | 2025 |
| Kibo Health Ltd | Health & social care | 2025 |
| Kicc Interiors Ltd | Construction | 2015 |
| Kickregenz Ltd | Other services | 2024 |
| Kics (South Wales) Ltd | Administrative & support | 2026 |
| Kids Cancer Charity | Health & social care | 2005 |
| Kids First Physio Ltd | Health & social care | 2025 |
| Kidwelly Pharmacy Limited | Wholesale & retail | 2007 |
| Kift Properties Ltd | Real estate | 2020 |
| Kilburn Holding Corporation Ltd | Construction | 2022 |
| Killa Shine Vehicle Body Repairs Ltd | Wholesale & retail | 2019 |
| Killashine Hereford Ltd | Wholesale & retail | 2025 |
| Killashine Tewkesbury Ltd | Wholesale & retail | 2026 |
| Killay Accountancy Services Limited | Professional & scientific | 2019 |
| Killay Cafe Ltd | Hospitality | 2020 |
| Killay Dental Health Centre Ltd | Health & social care | 2024 |
| Killay Fish Bar Ltd | Hospitality | 2022 |