| Keyless.Property Ltd | Construction | 2019 |
| Keystash Limited | Information & communication | 2020 |
| Kezakineticz Limited | Health & social care | 2022 |
| KF Plastering Ltd | Other services | 2025 |
| Khambalia Products Ltd | Wholesale & retail | 2024 |
| Khans Technologies Limited | Information & communication | 2021 |
| Kharbanda Limited | Real estate | 2019 |
| KHC Management Services Ltd | Water & waste | 2022 |
| KHO KHO Commercial Ltd | Real estate | 2024 |
| KHO KHO Kitchen Ltd | Hospitality | 2026 |
| Kickwords Limited | Professional & scientific | 2015 |
| KID Club London Limited | Wholesale & retail | 2026 |
| Kilima Properties Ltd | Real estate | 2014 |
| Kilimanjaro Tours Limited | Administrative & support | 2010 |
| Killer Group Limited | Construction | 2025 |
| Kimberley Residentials Ltd | Real estate | 2026 |
| Kimbers Construction Limited | Construction | 2017 |
| Kindred Companions Ltd | Health & social care | 2026 |
| Kinenao Ltd | Information & communication | 2024 |
| King's Funeral Directors Limited | Other services | 2015 |
| Kingdom Events Limited | Arts & recreation | 2025 |
| Kings Dental Specialists Limited | Health & social care | 2022 |
| Kingsend Holdings Ltd | Real estate | 2021 |
| Kingsend Properties Ltd | Real estate | 2015 |
| Kingsend Ruislip Management Limited | Real estate | 2011 |
| Kingsforth Construction Limited | Construction | 2019 |
| Kingsmere Construction Group Ltd | Construction | 2019 |
| Kins' Table Food and Events Ltd | Hospitality | 2024 |
| Kintsugi RE Limited | Construction | 2024 |
| Kirkview Construction Ltd | Construction | 2007 |
| Kirthan Limited | Wholesale & retail | 2008 |
| Kitchen Fitters (London) Limited | Construction | 2011 |
| Kitchenspacelondon Ltd | Construction | 2025 |
| KJ IT Consultancy Limited | Information & communication | 2010 |
| KJB Hospitality Ltd | Professional & scientific | 2024 |
| KK Restaurant and Bar Ltd | Hospitality | 2025 |
| KK Restaurant London Ltd | Hospitality | 2025 |
| KKZ Productions Ltd | Transport & logistics | 2015 |
| KL SFX Limited | Information & communication | 2023 |
| KLS Clinical Limited | Other services | 2014 |
| KML PUB Clean Limited | Administrative & support | 2019 |
| Kmldn Ltd | Construction | 2026 |
| Kmqs Services Ltd | Professional & scientific | 2023 |
| KND Analytics Limited | Information & communication | 2024 |
| Knyght Watches Limited | Wholesale & retail | 2020 |
| Kojo Properties Limited | Real estate | 2019 |
| Koko Shop Machine Co., Ltd. | Extraterritorial | 2013 |
| Koldashi Ltd | Real estate | 2024 |
| Konpalondon Entertainment CIC | Manufacturing | 2026 |
| Konxy Ltd | Wholesale & retail | 2024 |
| Korabandi Consulting Ltd | Information & communication | 2014 |
| Korea Treat Box Ltd | Wholesale & retail | 2020 |
| Korthwright Consultancy Ltd | Professional & scientific | 2014 |
| Koshal Family Partnership LLP | | 2019 |
| Kotian Consultancy Ltd | Extraterritorial | 2019 |
| Kottoro Limited | Real estate | 2025 |
| Koyi Ltd | Other services | 2013 |
| Kozik Property Assets Limited | Real estate | 2017 |
| KP Fitness Online Ltd | Arts & recreation | 2025 |
| Kpit Projects Limited | Information & communication | 2009 |
| KPK Management Limited | Real estate | 2020 |
| Kpnk Traders Limited | Wholesale & retail | 2021 |
| KPT Logistics Ltd | Transport & logistics | 2023 |
| Kratos Fitness Clubs Ltd | Arts & recreation | 2021 |
| Kream Developments Ltd | Real estate | 2016 |
| Kream Projects Ltd | Real estate | 2024 |
| Kream Properties Ltd | Real estate | 2007 |
| KRL Builders Ltd | Construction | 2019 |
| KS Bodymech Ltd | Wholesale & retail | 2025 |
| KS Interprise Ltd | Wholesale & retail | 2021 |
| KS UK Group Limited | Wholesale & retail | 2025 |
| KS UK Marketing Limited | Professional & scientific | 2025 |
| KS World Ltd | Transport & logistics | 2025 |
| KS08 Consultancy Limited | Administrative & support | 2019 |
| KSG Convenience Store Ltd | Wholesale & retail | 2020 |
| KSG Local Stores Ltd | Wholesale & retail | 2023 |
| Kshatradharma Ltd | Extraterritorial | 2019 |
| KSV Property Ltd | Real estate | 2024 |
| KT ML Services Limited | Information & communication | 2023 |
| KT Resources Limited | Construction | 2014 |
| KTB Commercial Ltd | Professional & scientific | 2020 |
| KTB Estates Limited | Construction | 2020 |
| KUK Finds Ltd | Wholesale & retail | 2025 |
| Kumon South Ruislip Ltd | Education | 2026 |
| Kumon Wembley Park Centre LLP | | 2013 |
| Kushiv Limited | Real estate | 2018 |
| Kuwei Group Limited | Wholesale & retail | 2021 |
| KVN Online Services Ltd | Wholesale & retail | 2019 |
| KVV Limited | Information & communication | 2012 |
| KW Business Solutions Limited | Administrative & support | 2015 |
| Kwame Contracts Ltd | Construction | 2018 |
| Kwantus Wealth Ltd | Professional & scientific | 2025 |
| Kwsbtv Limited | Information & communication | 2014 |
| KYC Coaching Limited | Professional & scientific | 2026 |
| KYG Black Swan Limited | Information & communication | 2022 |
| Kylo Energy Ltd | Construction | 2021 |
| L & K Builders Limited | Construction | 1998 |
| L Marshall Contractors Limited | Construction | 2013 |
| L White Properties Ltd | Real estate | 2025 |
| L.A.S. Homes Ltd | Real estate | 2021 |