| Just Electric Ltd | Construction | 2005 |
| Just Rolls Limited | Wholesale & retail | 2007 |
| Just Welding Limited | Manufacturing | 2016 |
| Juziux Ltd | Transport & logistics | 2021 |
| JW Auto's & Mechanical Services Limited | Wholesale & retail | 2019 |
| JW Minter Limited | Professional & scientific | 2021 |
| JWF Consultants Ltd | Professional & scientific | 2015 |
| JX Plumbing Limited | Construction | 2018 |
| Jyoti Wellness Ltd | Information & communication | 2026 |
| K & D Property Services and Management Ltd | Real estate | 2024 |
| K a Watts Electrical Limited | Extraterritorial | 2020 |
| K a Watts Plumbing & Heating Limited | Construction | 1999 |
| K a Watts Trustee Limited | Professional & scientific | 2021 |
| K C Joinery Services Limited | Construction | 2020 |
| K P Turner Limited | Information & communication | 2017 |
| K Roofing & Guttering Ltd | Construction | 2024 |
| K.H.R. Company Limited | Wholesale & retail | 1981 |
| K.O. Plant Groundworks Limited | Construction | 2006 |
| K.S. Sterling Ltd | Real estate | 2021 |
| K8 Technologies Private Limited | Information & communication | 2022 |
| KAF1618 Limited | Hospitality | 2026 |
| Kaisan Limited | Information & communication | 2026 |
| Kaisertech Limited | Wholesale & retail | 1998 |
| Kaixin Food Ltd | Hospitality | 2022 |
| Kaizen Wear Club Ltd | Wholesale & retail | 2024 |
| Kake ‘N’ Krumb Limited | Manufacturing | 2026 |
| Kalmont Construction Ltd | Construction | 2025 |
| Kalyan Holdings Limited | Financial services | 2025 |
| Kama Pawsitive Ltd | Wholesale & retail | 2025 |
| Kampango Ltd | Information & communication | 2014 |
| Kanara Fishery Ltd | Agriculture & fishing | 2017 |
| Kanes Properties Group Limited | Construction | 2020 |
| KAP Haulage Limited | Transport & logistics | 2023 |
| Karob Consulting Services Ltd | Professional & scientific | 2019 |
| Kashmir Tandoori Ltd | Hospitality | 2000 |
| Kate Bingham Interior Design Limited | Professional & scientific | 2005 |
| Katrine Highway Planning Ltd | Professional & scientific | 2019 |
| Kaur Dentistry Limited | Health & social care | 2024 |
| Kavod Digital Media & Publishing Services Ltd | Information & communication | 2023 |
| KAY Allan Timber Merchants Limited | Wholesale & retail | 2024 |
| Kayawe Ltd | Transport & logistics | 2023 |
| Kb-Lighting Limited | Manufacturing | 2016 |
| Kbmec Limited | Administrative & support | 2014 |
| KBS Structural Engineering Limited | Professional & scientific | 2021 |
| KCC Group Limited | Information & communication | 2025 |
| Kday Consultancy Ltd | Professional & scientific | 2018 |
| KDM Scaffolding Solutions Limited | Construction | 2025 |
| KDY Constructions Ltd | Construction | 2026 |
| Keanen Ltd | Professional & scientific | 2014 |
| Keenmead Limited | | 1982 |
| Keep Making AI Ltd | Information & communication | 2026 |
| Keep on Making Ltd | Information & communication | 2025 |
| Keepers Choice Foods Limited | Extraterritorial | 2006 |
| Kelda Showers Limited | Professional & scientific | 2009 |
| Kells Holdings Limited | Professional & scientific | 2002 |
| Kelly Griffiths Arts Limited | Professional & scientific | 2026 |
| Kelson Facades Ltd | Construction | 2019 |
| KEN Smith Solutions Limited | Information & communication | 2019 |
| Kent International College Limited | Education | 2023 |
| Kernow BIN Wash Ltd | Construction | 2017 |
| Kershaw Chauffeur Services Limited | Transport & logistics | 2022 |
| Kershaw Construction Limited | Construction | 2012 |
| Kershaw Property & Holdings Limited | Construction | 2012 |
| Kershaw Roofing Limited | Construction | 2005 |
| Keswick Small Franchise Limited | Wholesale & retail | 2026 |
| KEV Jones & SON Limited | Wholesale & retail | 2006 |
| Kevin Hurst Autos Limited | Wholesale & retail | 2003 |
| KEW Property Investments Ltd | Real estate | 2019 |
| Kew.G Projects Ltd | Construction | 2023 |
| Key Changes Music Therapy | Health & social care | 2008 |
| Key Transport Limited | Transport & logistics | 2002 |
| Keyair Limited | Transport & logistics | 2001 |
| Keypath Limited | Professional & scientific | 1995 |
| Kezion Cleaning Services Ltd | Administrative & support | 2026 |
| KFS Special Vehicles Limited | Professional & scientific | 2002 |
| KG Maintenance Ltd | Construction | 2018 |
| KGA Plus Limited | Transport & logistics | 2023 |
| Khalsaedge Ltd | Real estate | 2026 |
| Khang-Prisca Ltd | Health & social care | 2015 |
| Khloproperties Ltd | Real estate | 2025 |
| KHR Holding Company Limited | Professional & scientific | 2008 |
| Khushbzar Ltd | Health & social care | 2024 |
| Khwi Property Limited | Real estate | 2023 |
| KIDS2DAY Preschool Limited | Health & social care | 2024 |
| Kidson & Kidson Limited | Real estate | 2010 |
| Kilbracken Consulting Limited | Wholesale & retail | 2025 |
| Kilnsea Developments Limited | Real estate | 1992 |
| Kimber Property Holdings Limited | Real estate | 2015 |
| Kim’S Kleans Limited | Administrative & support | 2024 |
| King Harry Lane Management Company Limited | Households | 2011 |
| King Wigg Limited | Professional & scientific | 2019 |
| King's Court Masonic Centre Limited | Other services | 1968 |
| Kingfisher TMB Limited | Professional & scientific | 2000 |
| Kings Worthy Renovation Ltd | Households | 2022 |
| Kingshill (Cirencester) Management Limited | Households | 2010 |
| Kingsley Contracting Ltd | Construction | 2021 |
| Kingsmill Property Solutions Ltd | Real estate | 2024 |
| Kingswater Investments Limited | Real estate | 1989 |
| Kingsway Property Limited | Real estate | 2013 |
| Kingsway Residents Company Limited | Administrative & support | 2001 |