| Kalm HBF Ltd | Administrative & support | 2016 |
| Kamo 25 Ltd | Hospitality | 2025 |
| Kamtrad Limited | Financial services | 2015 |
| Kandibase.Io Ltd | Information & communication | 2026 |
| Kango Music Limited | Arts & recreation | 2003 |
| Kanopia Limited | Information & communication | 2012 |
| Kanrene Health Care Limited | Health & social care | 2025 |
| Kara's Kitchen Services Ltd | Wholesale & retail | 2025 |
| Karen Briggs Limited | Professional & scientific | 2023 |
| Kariwo Accountancy Ltd | Professional & scientific | 2026 |
| Karma Wellbeing Limited | Arts & recreation | 2024 |
| Karpachini Ltd | Transport & logistics | 2020 |
| Karri Consulting Limited | Administrative & support | 2024 |
| KAS Building Developments Limited | Health & social care | 2014 |
| Kash Business Services Ltd | Administrative & support | 2025 |
| Kash Butchers and Gerocer Ltd | Wholesale & retail | 2025 |
| Kasvisto Limited | Professional & scientific | 2015 |
| Katie's Life Kitchen Limited | Hospitality | 2020 |
| Katomba Solutions Limited | Administrative & support | 2026 |
| Kawira Limited | Health & social care | 2012 |
| Kaçak Group Limited | Professional & scientific | 2019 |
| KBA Cleaning Plus Ltd | Administrative & support | 2022 |
| KBJ Consulting Limited | Professional & scientific | 2024 |
| KCU Holdings Limited | Financial services | 2022 |
| KDC Events Ltd | Arts & recreation | 2019 |
| Kean Transport Ltd | Transport & logistics | 2019 |
| Keepsmilingks Ltd | Professional & scientific | 2023 |
| Keetel Ltd | Construction | 2022 |
| Kefrdiz Limited | Hospitality | 2013 |
| Keily Associates Limited | Professional & scientific | 2024 |
| Keily Inc Limited | Professional & scientific | 2014 |
| Keily Ltd | Professional & scientific | 2022 |
| Keisha's Accessories Limited | Wholesale & retail | 2021 |
| Keith Wood Production Solutions Ltd | Arts & recreation | 2018 |
| Kelly Formwork (UK) Limited | Construction | 2005 |
| Kelly Mccartney Ltd | Real estate | 2019 |
| Kempford Technologies Limited | Information & communication | 1995 |
| Kempley Tax Limited | Professional & scientific | 2021 |
| KEN Campbell & Co Ltd | Professional & scientific | 2012 |
| Kendal Court (Management) (NO.2) Limited | Real estate | 1996 |
| Kensington Gardens Residents Association Limited | Households | 1978 |
| Kent Security Services Ltd | Administrative & support | 2021 |
| Kentes Physio Ltd | Health & social care | 2018 |
| Keptware Ltd | Information & communication | 2019 |
| Kerrison Care Consultancy Ltd | Administrative & support | 2025 |
| Kevin James Limited | Information & communication | 1998 |
| Keymed (Medical & Industrial Equipment) Limited | Manufacturing | 1969 |
| Keymove Investment Holdings Limited | Real estate | 2020 |
| Keyplan Property Ltd | Real estate | 2026 |
| Keystone Foundry Ltd | Information & communication | 2026 |
| Kgmn Limited | Real estate | 2025 |
| Kgsa International Ltd | Wholesale & retail | 2019 |
| Khanala Construction Ltd | Construction | 2021 |
| Khawaja & Co. Limited | Professional & scientific | 2002 |
| Kieran LAI Ltd | Arts & recreation | 2023 |
| Kilosierra Ltd | Administrative & support | 2025 |
| Kimoh Investments Limited | Real estate | 2022 |
| Kinara Care Ltd | Health & social care | 2026 |
| Kinectu Ltd | Real estate | 2021 |
| Kingfisher Apparels Limited | Wholesale & retail | 1992 |
| Kingfisher Management Consultants Limited | Professional & scientific | 2011 |
| Kingpins Bowl Limited | Hospitality | 2016 |
| Kings Healthcare Practitioner Limited | Administrative & support | 2015 |
| Kingsgate Court Limited | Real estate | 1980 |
| Kingsgate Court Management Ltd | Households | 2021 |
| Kingsgate Owners GRP Limited | Households | 2009 |
| Kingsley Design Ltd | Professional & scientific | 2012 |
| Kingsmeade Westcliff-On-Sea RTM Company Limited | Real estate | 2006 |
| Kingsnorth Homes Ltd | Real estate | 2022 |
| Kingston Services Limited | Administrative & support | 2016 |
| Kingswood Leisure Services Holdings Limited | Extraterritorial | 2006 |
| Kingswood Leisure Services Limited | Wholesale & retail | 2006 |
| Kingswood Woodwork Limited | Construction | 2013 |
| Kink Hair Limited | Other services | 2007 |
| Kinson Court Management Company Limited | Households | 2000 |
| KIP Mcgrath Southend East LLP | | 2021 |
| Kirby & Sons Ltd | Professional & scientific | 2015 |
| Kishaan Food and Wine Ltd | Wholesale & retail | 2019 |
| Kitchen Disco Limited | Wholesale & retail | 2010 |
| Kitchens by Gregory Limited | Wholesale & retail | 2020 |
| Kittea Cakes Ltd | Hospitality | 2019 |
| Kiwi Capital Ltd | Financial services | 2025 |
| Kiwitune Motors Limited | Wholesale & retail | 2019 |
| KJ Pro Coatings Ltd | Construction | 2025 |
| KJL Document Solutions Limited | Information & communication | 2018 |
| KJL Group Limited | Financial services | 2023 |
| KK Builders Team Ltd | Construction | 2020 |
| KK Property Management Ltd | Real estate | 2019 |
| KK2025 Ltd | Wholesale & retail | 2002 |
| KKP News & Supermarket Limited | Wholesale & retail | 2019 |
| Kloosmans Ltd | Professional & scientific | 2014 |
| KLP Solutions Ltd | Public administration | 2023 |
| KM Decontamination Services Limited | Administrative & support | 2025 |
| Knak Construction Limited | Administrative & support | 2004 |
| Knetik Logistics Ltd | Transport & logistics | 2025 |
| Knightgate Ltd | Construction | 2020 |
| Knighthood Roofing Limited | Construction | 2025 |
| Knights Electrical Solutions Ltd | Extraterritorial | 2023 |
| Knights Gate and Castra Park Residents Management Company Limited | Households | 2025 |
| Knock-Knock (2DOOR) Limited | Construction | 2021 |