| K2 Medical Systems Holdings Limited | Manufacturing | 1999 |
| K2 Medical Systems Limited | Manufacturing | 1999 |
| K9 Security Services (South West) Limited | Administrative & support | 2000 |
| Kady Chatman Ltd | Professional & scientific | 2021 |
| Kandu Arts Community Projects CIC | Education | 2016 |
| Karen Crawford Limited | Professional & scientific | 2005 |
| Karen Sayers Limited | Professional & scientific | 2002 |
| Karensa Cottages Ltd | Real estate | 2024 |
| Karoli Limited | Manufacturing | 2007 |
| Kass Inn Ltd | Hospitality | 2018 |
| Kate E Reynolds Ltd | Information & communication | 2017 |
| Katherine Dempsey Limited | Wholesale & retail | 2025 |
| Katherine Gibbs Holdings Limited | Financial services | 2025 |
| Katherine Partis Limited | Wholesale & retail | 2007 |
| Katherine Smith Holdings Limited | Financial services | 2026 |
| Katie Terrington Private Travel Ltd | Administrative & support | 2018 |
| Katmax Properties Limited | Real estate | 2019 |
| Katmax UK Holdings Limited | Financial services | 2019 |
| Kaushik Group Ltd | Wholesale & retail | 2025 |
| Kayja Solutions Ltd | Information & communication | 2024 |
| KB Communications and Networks Limited | Information & communication | 2018 |
| Kbrdh Ltd | Health & social care | 2014 |
| KE Fitness Ltd | Health & social care | 2016 |
| KE2 Limited | Administrative & support | 2018 |
| Keenor Engineering Ltd | Information & communication | 2019 |
| Keith GAY Properties Limited | Real estate | 1974 |
| Keith Montgomery Associates Limited | Financial services | 1973 |
| Kelly Chiropractic Ltd | Health & social care | 2016 |
| Kelston Records Limited | Arts & recreation | 2016 |
| Kemento Ltd | Information & communication | 2018 |
| Kempsford Farms Limited | Agriculture & fishing | 2011 |
| Kemsales Limited | Administrative & support | 2004 |
| KEN Global Ltd | Arts & recreation | 2022 |
| Kenba Ltd | Professional & scientific | 2025 |
| Kenny & Karmen Limited | Real estate | 2021 |
| Kenver House Ltd | Health & social care | 2009 |
| Kepiru Ltd | Wholesale & retail | 2024 |
| Kerithbrook Associates Limited | Professional & scientific | 2018 |
| Kern Management Limited | Professional & scientific | 1997 |
| Kernetix Ltd | Information & communication | 2025 |
| Kerr Integration Limited | Professional & scientific | 2014 |
| Kerrie Leather Ltd | Professional & scientific | 2018 |
| Keshi Home Ltd | Real estate | 2026 |
| Keskins Chippenham Ltd | Hospitality | 2023 |
| Kestemont Enterprises Ltd | Financial services | 2024 |
| Kevco (UK) Limited | Administrative & support | 1998 |
| Kevin Tiley Commercial & Debt Recovery UK Limited | Administrative & support | 2015 |
| Kevin Tiley Group Limited | Professional & scientific | 2023 |
| Kevin Tiley Legal Services Ltd | Administrative & support | 2025 |
| Kevin&Sarah Ltd | Transport & logistics | 2021 |
| Key Tags Limited | Professional & scientific | 2000 |
| Keynsham Waterfront Ltd | Transport & logistics | 2016 |
| Keywaygo Limited | Wholesale & retail | 2024 |
| Kibswell Homes Limited | Construction | 1970 |
| Kidd Aitken ESG Limited | Professional & scientific | 2025 |
| KIM Nilsson Ltd | Professional & scientific | 2023 |
| Kime Enterprises Ltd | Financial services | 2024 |
| Kinch Consulting Services Limited | Administrative & support | 2025 |
| Kinder Holdings Ltd | Financial services | 2017 |
| Kingfisher Farm Services Ltd | Agriculture & fishing | 2013 |
| Kingfisher House Holdings Ltd | Real estate | 2025 |
| Kingsplay Farming Company Limited | Agriculture & fishing | 2003 |
| Kingsplay Legal Limited | Professional & scientific | 2021 |
| Kingston Hill Farm Ltd | Agriculture & fishing | 2010 |
| Kingswood Caravan & Camping Centre Limited | Wholesale & retail | 2001 |
| Kington Computer Services Ltd | Information & communication | 2024 |
| Kington Langley Stud Ltd | Agriculture & fishing | 1998 |
| Kintsugi Commerce Ltd | Wholesale & retail | 2023 |
| Kipper Media Limited | Professional & scientific | 2017 |
| Kirsty Ducksmith Ltd | Administrative & support | 2019 |
| Kite Woodworks Ltd | Manufacturing | 2024 |
| Kitty's Housekeeping Services Ltd | Administrative & support | 2026 |
| KJD Brokers Ltd | Financial services | 2023 |
| KJJ Lettings LLP | | 2021 |
| KK Partners Ltd | Construction | 2012 |
| Kleonne Limited | Wholesale & retail | 2024 |
| Kleonne Logistics Limited | Financial services | 2025 |
| Kleonne Scan Limited | Information & communication | 2026 |
| Klukowski Building Company Ltd | Construction | 2024 |
| KM Farm Parts Limited | Extraterritorial | 2011 |
| KMC Construction Limited | Construction | 2011 |
| KME Designs Limited | Wholesale & retail | 2021 |
| KMK Store Limited | Manufacturing | 2023 |
| Kmoo Ltd | Extraterritorial | 2026 |
| Knead Bakery Limited | Manufacturing | 2020 |
| Knight Surveying Services Ltd | Professional & scientific | 2025 |
| Knights Folly Limited | Administrative & support | 2014 |
| Knightsbridge Personal & Corporate Ltd | Professional & scientific | 2019 |
| Knightsbridge Private Clients Ltd | Real estate | 2020 |
| Knoll (Somerset) Ltd | Agriculture & fishing | 2019 |
| Koba Holdings Limited | Administrative & support | 2019 |
| Kodoo Consulting Ltd | Information & communication | 2019 |
| Kompact Renewables Ltd | Professional & scientific | 2023 |
| KOP Care Services Ltd | Health & social care | 2017 |
| Koti Saunas Ltd | Other services | 2024 |
| KP Care Solutions Ltd | Public administration | 2022 |
| KP Stratasec Ltd | Construction | 2025 |
| KP Trades Ltd | Wholesale & retail | 2026 |
| KPG PM Limited | Administrative & support | 2012 |
| KPM Holdings Ltd | Administrative & support | 2022 |