| Joseph's Brothers Limited | Hospitality | 2019 |
| Joshee Asset Management Ltd | Real estate | 2022 |
| JPR Surveyors Ltd | Professional & scientific | 2017 |
| Jrds Estates Ltd | Real estate | 2026 |
| JSJ Property Management Limited | Real estate | 2018 |
| JSP Property Holdings LLP | | 2023 |
| Juggernaut Group Holdings Limited | Financial services | 2025 |
| Juldee Ltd | Extraterritorial | 2013 |
| Junecourt Limited | Wholesale & retail | 1976 |
| Juniper House Care Ltd | Health & social care | 2026 |
| Jupiter Wealth Management Ltd | Financial services | 2024 |
| Just Chillies Limited | Wholesale & retail | 2023 |
| Just FIX That Ltd | Construction | 2017 |
| JV Holiday Lettings Ltd | Real estate | 2021 |
| JVC - Delta Investment Limited | Real estate | 2019 |
| Jvc-Delta Investment (Holdings) Limited | Financial services | 2023 |
| Jvma Ltd | Health & social care | 2016 |
| Jvproperty Lettings Ltd | Real estate | 2017 |
| Jyavin Ltd | Financial services | 2026 |
| K Kouture London Limited | Wholesale & retail | 2025 |
| K P Gayatri Ltd | Real estate | 2019 |
| K Shankla Ltd | Real estate | 2019 |
| K&R Building & Projects Ltd | Construction | 2023 |
| K&S Motors Ltd | Wholesale & retail | 2024 |
| K5 Residential Limited | Real estate | 2024 |
| Kaar Properties Ltd | Real estate | 2019 |
| Kaashay Investments Limited | Real estate | 2017 |
| Kaiser Construction Limited | Construction | 2013 |
| Kajoli Art and Design Limited | Construction | 2026 |
| Kalkye Limited | Financial services | 2016 |
| Kalpyog Ltd | Administrative & support | 2005 |
| Kamani Records Limited | Information & communication | 2020 |
| Kandies Ltd | Wholesale & retail | 2017 |
| Kane Group Limited | Professional & scientific | 1991 |
| Kanti Investments Ltd | Administrative & support | 2003 |
| Kapital Consulting Ltd | Information & communication | 2011 |
| Kapoga Ltd | Professional & scientific | 2019 |
| Karanios Ltd | Construction | 2020 |
| Karen Koutandos Embalming Services Limited | Other services | 2018 |
| Karon Commodities & Investments Ltd | Extraterritorial | 2002 |
| Kartar Food & Wine Ltd | Wholesale & retail | 2019 |
| Kartech Consultancy Ltd | Information & communication | 2019 |
| Kasa Properties (London) Limited | Households | 2017 |
| Kash Consulting Ltd | Information & communication | 2015 |
| Kashyapa & Company Limited | Real estate | 2016 |
| Kashyapa Dental Limited | Health & social care | 2019 |
| Kaslin Homes Limited | Hospitality | 2025 |
| Kasp Investments Ltd | Real estate | 2020 |
| Kaurten Properties Limited | Households | 2026 |
| Kaushik Consultants Limited | Professional & scientific | 2021 |
| Kavs Holdings Ltd | Real estate | 2024 |
| Kavs Property Ltd | Real estate | 2024 |
| Kawthar Investments Ltd. | Financial services | 2025 |
| Kayshudhi Ltd. | Other services | 2021 |
| Kbmr Ltd | Transport & logistics | 2024 |
| KDK Property Services Ltd | Households | 2025 |
| Kdpp Limited | Administrative & support | 2017 |
| Keady Limited | Construction | 2019 |
| Keemat Ltd | Real estate | 2026 |
| Keep Study Simple Ltd | Education | 2022 |
| Kemps Construction Limited | Construction | 2007 |
| Kenbright Ltd | Real estate | 2021 |
| Kendall Manor Limited | Households | 2008 |
| Kenilak Investments Limited | Construction | 1990 |
| Kenilak Properties Limited | Real estate | 2015 |
| Kennedy Travel (Yorkshire) Limited | Administrative & support | 1977 |
| Kensington Global Ltd | Wholesale & retail | 2017 |
| Kent Consultancy Limited | Professional & scientific | 2023 |
| Kernow Facets Limited | Wholesale & retail | 2003 |
| Kernow Telecom Ltd | Information & communication | 1999 |
| Keshav Consultancy Limited | Wholesale & retail | 2021 |
| Kevin Allen Haulage Ltd | Transport & logistics | 2016 |
| Kevnom Protection Ltd | Wholesale & retail | 2018 |
| Kewferry Drive Residents' Company Limited | Professional & scientific | 1996 |
| KH Invest Ltd | Financial services | 2018 |
| Khanna Family Holdings Limited | Hospitality | 2022 |
| Khariwal Associates Ltd | Other services | 2007 |
| Khariwal Consultants Ltd | Professional & scientific | 2023 |
| Khatas Ltd | Professional & scientific | 2024 |
| Khiroya FT Ltd | Real estate | 2014 |
| Khubi Solutions Ltd | Information & communication | 2008 |
| Kiki Shushu Limited | Wholesale & retail | 2025 |
| Kind Brands Limited | Wholesale & retail | 2014 |
| Kineta Limited | Health & social care | 2021 |
| Kinetic Financial Services Ltd | Financial services | 2026 |
| Kingfisher White Services Limited | Manufacturing | 2008 |
| Kings Hotel (UK) Limited | Hospitality | 2005 |
| Kingsbrook Residents Association Limited | Households | 2017 |
| Kingsfield Court Care Ltd | Health & social care | 2018 |
| Kingston International Film Festival Limited | Arts & recreation | 2021 |
| Kingston Park Ltd | Real estate | 2018 |
| Kingston Properties (London) Limited | Administrative & support | 1996 |
| Kirishna Property Investment Ltd | Real estate | 2022 |
| Kirom Limited | Extraterritorial | 2014 |
| Kismat Cargo Ltd | Transport & logistics | 2025 |
| KIT Gordon Limited | Information & communication | 2025 |
| Klean Aura Ltd | Wholesale & retail | 2025 |
| Kmdimensions Ltd | Professional & scientific | 2012 |
| KNA Property Investments Ltd | Real estate | 2022 |
| Knight Hawk Investments Limited | Real estate | 2020 |