| Kilit Star Ltd | Construction | 2022 |
| Killick Martin & Company Limited | Transport & logistics | 2017 |
| KIM Lawless Limited | Education | 2017 |
| Kimberly Healthcare Limited | Administrative & support | 2025 |
| KIN Supplies Limited | Other services | 2015 |
| Kind Care Agency Limited | Health & social care | 2022 |
| Kinder Kidz Day Nursery Limited | Health & social care | 2022 |
| Kindred Beauty Therapy Ltd | Other services | 2019 |
| Kinetic Commerce Ltd | Wholesale & retail | 2024 |
| Kingdom Quisine DU Lami(Ltd) Ltd | Hospitality | 2022 |
| Kingfisher (EU) Limited | Construction | 2011 |
| Kings Chapel Holdings Ltd | Financial services | 2025 |
| Kings Group of Companies Ltd | Other services | 2020 |
| Kingsley Consultation Ltd | Administrative & support | 2019 |
| Kingspan Technical Insulation Limited | Construction | 2005 |
| Kingsteam Mining Finance Ltd | Financial services | 2012 |
| Kingsway Cargo and Recovery Services Ltd | Wholesale & retail | 2020 |
| Kingswood Electronic Services Limited | Other services | 1997 |
| Kingswood Medical Services Limited | Health & social care | 2015 |
| Kingswood of Basildon Limited | Real estate | 2011 |
| Kingswood Sports Centre Limited | Arts & recreation | 1966 |
| Kingzvilla Ltd | Real estate | 2025 |
| Kinzy Fabrications & Machining Ltd | Manufacturing | 2024 |
| KIP Mcgrath Basildon Limited | Education | 2017 |
| KIP Mcgrath Tuition Basildon LP | | 2015 |
| Kiran K Limited | Other services | 2021 |
| Kirpa Construction Essex Ltd | Construction | 2025 |
| Kish Property Ltd | Real estate | 2023 |
| Kitchens & Bedrooms Design Ltd | Construction | 2022 |
| Kitchens Finest Limited | Hospitality | 2025 |
| Kith & KIN Projects Limited | Professional & scientific | 2015 |
| Kittykamp UK Limited | Agriculture & fishing | 2025 |
| Kj's Tiling Limited | Construction | 2019 |
| Kkab Limited | Professional & scientific | 2014 |
| Kkmart Bazaaar Ltd | Wholesale & retail | 2026 |
| Klassprefect Limited | Information & communication | 2020 |
| KLD Groundworks & Labour Supplies Limited | Construction | 2018 |
| Klean & Kleanse Limited | Administrative & support | 2025 |
| Klicco Limited | Professional & scientific | 2025 |
| Klinstar Ltd | Construction | 2019 |
| KLP Rail Limited | Other services | 2021 |
| KLS Fashion Ltd | Wholesale & retail | 2011 |
| KMC Communications Ltd | Information & communication | 2020 |
| Kmda Limited | Construction | 2024 |
| KMJ Construction Ltd | Construction | 2010 |
| KMJ Property Investments Limited | Real estate | 2025 |
| KMT Training & Consultancy Limited | Professional & scientific | 2019 |
| Knight-Life Entertainment Ltd | Information & communication | 2019 |
| Knockout Utilities Limited | Professional & scientific | 2024 |
| Knots and Dreams Ltd | Wholesale & retail | 2022 |
| KNS1 Ltd | Real estate | 2020 |
| KO Securities Limited | Administrative & support | 2014 |
| Kobo Consulting Ltd | Information & communication | 2015 |
| Kodikattu Enterprises Limited | Wholesale & retail | 2024 |
| Koftee Logistics Limited | Transport & logistics | 2019 |
| Koiosolve Limited | Information & communication | 2023 |
| Koki's Café Ltd | Hospitality | 2024 |
| Konica Minolta Business Solutions (UK) Limited | Information & communication | 1973 |
| Konica Minolta Business Solutions (Wales) Limited | Information & communication | 1969 |
| Konica Minolta Printing Solutions (UK) Limited | Extraterritorial | 1989 |
| Kope Consulting Limited | Professional & scientific | 2007 |
| Korev Construction Ltd | Construction | 2022 |
| Kosaka Motors Ltd | Wholesale & retail | 2019 |
| Kostas Services Limited | Construction | 2016 |
| Kosty FAB Ltd | Wholesale & retail | 2023 |
| Koundinya Limited | Professional & scientific | 2023 |
| Koushik and Kayan Limited | Real estate | 2023 |
| KP Car Repairs Ltd. | Wholesale & retail | 2009 |
| KPK Enterprises Ltd | Wholesale & retail | 2021 |
| KQS Consultancy Ltd | Professional & scientific | 2026 |
| KR Construction Management Ltd | Real estate | 2018 |
| Kris Brown Coach Enterprise Ltd | Arts & recreation | 2025 |
| Krish Property and Investment Ltd | Real estate | 2023 |
| Krish Trading and Export Ltd | Administrative & support | 2023 |
| Kriya Performing Arts Limited | Arts & recreation | 2026 |
| KRS Design & Developments Limited | Construction | 2024 |
| Kruse Electrical Services Ltd | Construction | 2019 |
| Krystal Architecture Limited | Professional & scientific | 2017 |
| Krystal Build Ltd | Construction | 2026 |
| KS & Co Properties Ltd | Real estate | 2025 |
| KSA Property Investments Limited | Real estate | 2020 |
| KSC Asset Company Limited | Administrative & support | 2025 |
| Ksd's Construction Limited | Construction | 2024 |
| KSS Smart Mart Ltd | Wholesale & retail | 2022 |
| KSW Autos Ltd | Wholesale & retail | 2024 |
| KT Scaffolding Ltd | Construction | 2017 |
| Kudos Asbestos Ltd | Other services | 2013 |
| Kuehlspeed International Ltd | Transport & logistics | 2012 |
| Kullan Limited | Hospitality | 2023 |
| Kultard Limited | Wholesale & retail | 2025 |
| Kushi GP Ltd | Hospitality | 2016 |
| KVB Residential Limited | Real estate | 2017 |
| Kviz Ltd | Professional & scientific | 2020 |
| KW Plumbing Limited | Construction | 2016 |
| Kwame Lawson Ltd | Professional & scientific | 2022 |
| KWC Electrical Limited | Construction | 2020 |
| KWH FFF Coaching LLP | | 2025 |
| Kwiki GIN Limited | Wholesale & retail | 2022 |
| Kwt.Plumbing & Heating Ltd | Water & waste | 2023 |
| KX Safety Ltd | Education | 2014 |