| JX Technology Limited | Information & communication | 2017 |
| Jzsmartrepairs Ltd | Administrative & support | 2025 |
| K & S London 8 Limited | Other services | 2017 |
| K E F Consultancy Limited | Administrative & support | 2018 |
| K J M Construction Group Ltd | Construction | 2025 |
| K M Electrical Wholesale Ltd | Wholesale & retail | 2011 |
| K M Shinnick Ltd | Construction | 2015 |
| K Salisbury Compliance Ltd | Public administration | 2023 |
| K Tiffins Ltd | Hospitality | 2018 |
| K Viktoria K Ltd | Manufacturing | 2016 |
| K&A Solutions Limited | Professional & scientific | 2020 |
| K&J Interiors Fit OUT Ltd | Construction | 2016 |
| K2DT Pathanalytica Ltd | Health & social care | 2022 |
| KA Fitted Interiors Ltd | Manufacturing | 2024 |
| Kaamos Limited | Health & social care | 2016 |
| Kaantimur Ltd | Real estate | 2022 |
| Kabala Limited | Health & social care | 2019 |
| Kachi & Kido Limited | Health & social care | 2024 |
| Kaddesh Limited | Health & social care | 2023 |
| Kadir Trans Ltd | Transport & logistics | 2019 |
| KAEDI0712 Ltd | Health & social care | 2015 |
| KAIROS1 Ltd | Arts & recreation | 2024 |
| KAIROS11 Ltd | Arts & recreation | 2026 |
| Kakaron Services Limited | Wholesale & retail | 2022 |
| Kaliko Dwellings Limited | Real estate | 2023 |
| Kamko Property Holdings Ltd | Real estate | 2026 |
| Kamkob Ltd | Health & social care | 2025 |
| Kamm Healthcare Service Limited | Health & social care | 2018 |
| Kamzi Healthcare Services Ltd | Health & social care | 2023 |
| Kane Pettican Limited | Professional & scientific | 2018 |
| Kanz Group Limited | Wholesale & retail | 2011 |
| KAO Data Limited | Financial services | 2019 |
| KAO Manufacturing Technology Limited | Manufacturing | 2019 |
| Kaolaw Accountants Ltd | Professional & scientific | 2025 |
| Kapalin Holdings Limited | Financial services | 2025 |
| Kapital Vision Limited | Other services | 2017 |
| Kaps Investments Ltd | Real estate | 2024 |
| Karama International Trading Company Ltd | Wholesale & retail | 2019 |
| Kare Medical Group Ltd | Health & social care | 2025 |
| Karemi Properties Limited | Real estate | 2019 |
| Kargohub Ltd | Transport & logistics | 2026 |
| Karl's Counselling Ltd | Health & social care | 2026 |
| Karm Care Limited | Health & social care | 2022 |
| Karnish Ltd | Wholesale & retail | 2021 |
| Kartal Catering Ltd | Wholesale & retail | 2023 |
| Karw Trans Limited | Transport & logistics | 2014 |
| KAS Mezz Ltd | Construction | 2015 |
| KAS Solution Ltd | Real estate | 2025 |
| Kashworth Consulting Limited | Professional & scientific | 2023 |
| Kashworth Trading Limited | Wholesale & retail | 2020 |
| Kasrey Limited | Real estate | 2024 |
| Katalyst Health Ltd | Health & social care | 2023 |
| Katapowsis Consulting Ltd | Information & communication | 2024 |
| Kavia Properties Ltd | Real estate | 2024 |
| Kavica Ltd | Hospitality | 2019 |
| Kaweesa Holdings Limited | Manufacturing | 2025 |
| KAY & KAY Properties Ltd | Real estate | 2024 |
| Kaya Fashions Limited | Manufacturing | 2023 |
| Kayandconsult Limited | Information & communication | 2023 |
| Kayanna Company Limited | Health & social care | 2022 |
| Kaybel Catering Limited | Hospitality | 2025 |
| Kayfas Health Ltd | Health & social care | 2018 |
| Kayl Security Systems Ltd | Professional & scientific | 2019 |
| Kaylea B Artistry Ltd | Other services | 2025 |
| Kaytai Ltd | Real estate | 2025 |
| Kaz's Archers Dart Ltd | Hospitality | 2017 |
| KB Building Property Ltd | Real estate | 2025 |
| KB Global Tech Group Ltd | Administrative & support | 2025 |
| KB Harlow Limited | Hospitality | 2023 |
| KC Group Construct UK Ltd | Transport & logistics | 2020 |
| KC Property Consulting Ltd | Real estate | 2018 |
| KCA Partitioning Supplies Ltd | Wholesale & retail | 2021 |
| Kcgrp Ltd | Administrative & support | 2025 |
| Kcomply Consulting Ltd | Financial services | 2012 |
| KD 1 Limited | Information & communication | 2020 |
| KD 10 Limited | Information & communication | 2025 |
| KD 2 Limited | Information & communication | 2020 |
| KD 5 Limited | Information & communication | 2022 |
| KD 6 Limited | Information & communication | 2022 |
| KD 6A Limited | Energy | 2020 |
| KD 8 Limited | Information & communication | 2024 |
| KD 9 Holdco Limited | Financial services | 2025 |
| KD 9 Limited | Information & communication | 2025 |
| KD Electrical Solutions Limited | Construction | 2012 |
| KD Holdco Limited | Financial services | 2025 |
| KD Midco Limited | Financial services | 2023 |
| KD Opco Limited | Financial services | 2023 |
| KD Servco Limited | Financial services | 2023 |
| KD Topco Limited | Financial services | 2025 |
| KD6B Limited | Energy | 2021 |
| KDK Electric and Heating Ltd | Construction | 2020 |
| KDL Contractors Ltd | Construction | 2019 |
| KDP Investments Limited | Financial services | 2013 |
| KDS Atelier Fine Flooring Ltd | Construction | 2025 |
| Keatings Heating Limited | Construction | 2016 |
| Kebble Environmental Services (UK) EOT Limited | Extraterritorial | 2024 |
| Kebble Environmental Services (UK) Limited | Professional & scientific | 2005 |
| Kecci Property Limited | Real estate | 2022 |
| Keepabeat First AID Hertfordshire Ltd | Education | 2023 |
| Kefran Holdings Limited | Financial services | 2010 |