| Just Leaflets and Catalogues Limited | Real estate | 1980 |
| Just Leap Limited | Professional & scientific | 2021 |
| Just Play Products Ltd | Manufacturing | 2020 |
| Just Reading Limited | Professional & scientific | 2009 |
| Just Travel Ltd | Administrative & support | 2023 |
| Just US Therapy Ltd | Extraterritorial | 2020 |
| JV Accountancy Ltd | Professional & scientific | 2018 |
| JVF Audio Limited | Arts & recreation | 2025 |
| JVR Gardens & Pools Limited | Administrative & support | 2020 |
| JVS Cars of Distinction Ltd | Wholesale & retail | 2020 |
| JW GAS Limited | Other services | 2016 |
| Jwoods Solutions Ltd | Information & communication | 2018 |
| Jwsempp Trustees Limited | Professional & scientific | 2006 |
| JY Consulting Ltd | Information & communication | 2021 |
| K & J Colours Limited | Manufacturing | 2026 |
| K Constructions Ltd | Construction | 2014 |
| K D a Software Consultants Ltd | Information & communication | 1995 |
| K F C Advertising Limited | Administrative & support | 1974 |
| K Kutz Barbering Ltd | Other services | 2021 |
| K W Developments Limited | Construction | 2014 |
| K&Dp Ltd | Professional & scientific | 2016 |
| K&M Consulting Services Ltd | Professional & scientific | 2025 |
| K&N Build Ltd | Construction | 2026 |
| K&N Knaphill Limited | Other services | 2025 |
| K-Squared Emea Limited | Information & communication | 2013 |
| K8 Design and Marketing Limited | Professional & scientific | 2008 |
| K9 and Feline Pet Services Limited | Administrative & support | 2011 |
| Kabe Services Limited | Transport & logistics | 2022 |
| Kachina Capital Limited | Professional & scientific | 2013 |
| KAE Trading Ltd | Wholesale & retail | 2025 |
| KAF Designs Ltd | Wholesale & retail | 2022 |
| KAG Recovery & Rehab Limited | Health & social care | 2026 |
| KAH Homes Ltd | Real estate | 2023 |
| Kaia Studio Ltd | Professional & scientific | 2025 |
| Kaitoke Healthcare Limited | Health & social care | 2025 |
| Kaliber International CIC | Information & communication | 2019 |
| Kalimah Ltd | Real estate | 2024 |
| Kalinin Software Ltd | Information & communication | 2024 |
| Kalm Training & Design Limited | Education | 2013 |
| KAM Abbey-Links Ltd | Administrative & support | 2025 |
| Kama Property Group Ltd | Real estate | 2026 |
| Kamali Group Limited | Professional & scientific | 2019 |
| Kamozo Ltd | Information & communication | 2015 |
| Kanishk Enterprises Ltd | Information & communication | 2013 |
| Kanonkop Consulting Ltd | Professional & scientific | 2018 |
| Kansak Ltd | Real estate | 2013 |
| Kape Marketing Limited | Professional & scientific | 2011 |
| Kappa Consultancy Ltd | Information & communication | 2022 |
| KAR Cafe Ltd | Hospitality | 2023 |
| Kara Guildford Limited | Other services | 2025 |
| Karak Chaii Woking Limited | Hospitality | 2024 |
| Karbon Contract Holdings Ltd | Financial services | 2022 |
| Karedo Estates Limited | Real estate | 2020 |
| Karedo Ltd | Information & communication | 2007 |
| Karim Capital Advisory Ltd | Financial services | 2026 |
| Karimos Management Ltd | Other services | 2016 |
| Karlsimon Limited | Other services | 2014 |
| Karod Ltd | Wholesale & retail | 2019 |
| Karoh AI Limited | Information & communication | 2026 |
| Karolz Transport Ltd | Transport & logistics | 2023 |
| Kartzo. Ltd | Wholesale & retail | 2025 |
| Kashm 2 Ltd | Real estate | 2025 |
| Kashm Holdings Ltd | Real estate | 2022 |
| Kate Sobczak Consulting Ltd | Professional & scientific | 2022 |
| Kaunain Digital Co Ltd | Wholesale & retail | 2024 |
| Kavulilo Ventures Ltd | Health & social care | 2024 |
| Kayne Travel Ltd | Administrative & support | 2018 |
| KB@17 Ltd | Professional & scientific | 2016 |
| KC Legal Consulting Limited | Professional & scientific | 2026 |
| KC Stratigraphic Limited | Professional & scientific | 2019 |
| Kcma Dropshipping Ltd | Wholesale & retail | 2024 |
| Kcpr Kateclarkpr Ltd | Professional & scientific | 2016 |
| KDB Door Business UK Ltd | Manufacturing | 2025 |
| Kealay Adam Limited | Construction | 2018 |
| Kealay Construction Limited | Construction | 2000 |
| Keane Accountancy Limited | Professional & scientific | 2025 |
| Keartland & Co Limited | Professional & scientific | 2019 |
| Keeble Consulting Limited | Professional & scientific | 2014 |
| Keele Hotel Developments Limited | Construction | 2018 |
| Keele Hotel Tenant Limited | Hospitality | 2018 |
| Keen Consultants Ltd | Information & communication | 2019 |
| Keep Green Ltd | Hospitality | 2025 |
| Keeping Bizzy Ltd | Manufacturing | 2013 |
| Kein Consulting Ltd | Professional & scientific | 2024 |
| Kelly Private Wealth Ltd | Wholesale & retail | 2023 |
| Kelso Commercial Limited | Real estate | 2020 |
| Kendall Sports Therapy Ltd | Health & social care | 2018 |
| Kendrick Bros.-Concrete Limited | Professional & scientific | 1963 |
| Kenneth G.Hayes Limited | Real estate | 1955 |
| Kensworth Plotholders Limited | Real estate | 2012 |
| Kent Energies UK Ltd. | Professional & scientific | 2021 |
| Kent Global PLC | Financial services | 2021 |
| Kent House (Guildford) Limited | Households | 1985 |
| Kent International Arabia Limited | Professional & scientific | 2021 |
| Kent International Services Limited | Professional & scientific | 1986 |
| Kent UK Technical Services Limited | Construction | 2021 |
| Kentucky Fried Chicken (Great Britain) Limited | Hospitality | 1969 |
| Kentucky Fried Chicken Limited | Professional & scientific | 1964 |
| Kepler Events Ltd | Administrative & support | 2023 |
| Kerala Health Care Limited | Health & social care | 2019 |