| Kenyans in Reading FUN Day Ltd | Arts & recreation | 2019 |
| KENZO88SWINDON Limited | Hospitality | 2024 |
| Kerean Consultancy Limited | Health & social care | 2021 |
| Kernon Countryside Consultants Ltd | Professional & scientific | 2011 |
| Kerr Consulting Group Limited | Professional & scientific | 2021 |
| Kerr Enterprise Holdings Limited | Administrative & support | 2008 |
| Kerr Office Group Limited | Wholesale & retail | 2000 |
| Kerr Office Supplies Limited | Administrative & support | 2008 |
| Kerri Drywall Ltd | Construction | 2012 |
| Kerry Care Collective Ltd | Health & social care | 2025 |
| Kerry on Care Ltd | Health & social care | 2022 |
| KESS2024 Limited | Professional & scientific | 2024 |
| Kesserf Company Limited | Health & social care | 2022 |
| Kester Services Ltd | Professional & scientific | 2021 |
| Kestrel Audio Ltd | Manufacturing | 2022 |
| Kestrel Building Services Limited | Construction | 2017 |
| Kestrel Tscm Ltd | Information & communication | 2025 |
| Keswick House RTM Company Ltd | Households | 2009 |
| Ketha Petroleum Ltd | Wholesale & retail | 2018 |
| Kettering Venture Park Management Limited | Real estate | 1989 |
| Keuch Ltd | Professional & scientific | 2022 |
| Kevinkurlej Ltd | Construction | 2025 |
| Kewjay Ltd | Information & communication | 2023 |
| Key Financial Consulting Ltd | Financial services | 2020 |
| Key Move Property Agents Ltd | Real estate | 2024 |
| Key Performance Training Ltd | Other services | 2017 |
| Key Security Limited | Administrative & support | 2009 |
| Key-Resource Limited | Construction | 2009 |
| Keyan Properties Limited | Real estate | 2025 |
| Keymill Property Group Ltd | Real estate | 2022 |
| Keynoch Ltd | Real estate | 2025 |
| Keyosha Ltd | Wholesale & retail | 2021 |
| Keyprocessor Ltd | Construction | 2018 |
| Keystone Conference & Event Management Limited | Professional & scientific | 2019 |
| Keywise Solutions Limited | Wholesale & retail | 2024 |
| KF Physio Ltd | Health & social care | 2022 |
| KFR Engineering Ltd | Professional & scientific | 2026 |
| KG Carpentry & Joinery Ltd | Construction | 2022 |
| KGM UK Motors Ltd | Wholesale & retail | 2007 |
| KH Engineering (Swindon) Limited | Manufacturing | 2008 |
| Khaja Swindon Ltd | Hospitality | 2025 |
| Khalsa Holdings Ltd | Real estate | 2025 |
| Khan Adamson Limited | Professional & scientific | 2002 |
| Khans Estate Holdings Ltd | Real estate | 2021 |
| Kharis Praise Church Limited | Other services | 2023 |
| Khata Care Ltd | Health & social care | 2022 |
| Khem Health Limited | Health & social care | 2022 |
| KHO Drylining Limited | Construction | 2017 |
| Khosravani Productions Ltd | Information & communication | 2023 |
| Khush Distributions Ltd | Transport & logistics | 2021 |
| Kian Trading Ltd | Wholesale & retail | 2026 |
| Kiani Constructions Limited | Construction | 2023 |
| Kidson-Trigg Limited | Real estate | 2005 |
| Kidwood Ltd | Real estate | 2022 |
| Kieljan Limited | Transport & logistics | 2011 |
| Kifah Geoground Ltd | Professional & scientific | 2025 |
| Kilbenny Co Ltd | Professional & scientific | 2022 |
| Kilimanjaro Children Homes Limited | Health & social care | 2024 |
| Killstat Limited | Extraterritorial | 2002 |
| Kiln Graphic Ltd | Professional & scientific | 2020 |
| Kilpatrick & Co Commercial Property Consultants Limited | Professional & scientific | 2011 |
| KIM Trade&Distribution Ltd | Transport & logistics | 2020 |
| Kimber & Jackson Decorating Specialists Limited | Construction | 2023 |
| Kimber Care Limited | Health & social care | 2007 |
| Kimber Tech Limited | Professional & scientific | 2011 |
| Kimc Limited | Professional & scientific | 2014 |
| Kimkab Limited | Information & communication | 2025 |
| Kimmeridge Close Residents Company Limited | Households | 1974 |
| Kimmi's Cakes Ltd | Manufacturing | 2017 |
| KIN Photographs Limited | Professional & scientific | 2021 |
| KIN Reformer Studios Ltd | Arts & recreation | 2026 |
| Kind London Ltd | Wholesale & retail | 2018 |
| Kindara Support Ltd | Health & social care | 2025 |
| Kindred Developments Ltd | Real estate | 2025 |
| Kinesis Integration Limited | Information & communication | 2014 |
| King Building Services Ltd | Construction | 2023 |
| King Computer Services Limited | Information & communication | 2010 |
| King Industrial Products Limited | Wholesale & retail | 1980 |
| King William Street CE Primary School | Education | 2012 |
| Kingdom Heritage Group Limited | Professional & scientific | 2025 |
| Kingdom Property Lettings Limited | Construction | 2007 |
| Kingdom Youth Services Limited | Health & social care | 2020 |
| Kingfisher Print and Design Limited | Manufacturing | 2018 |
| Kingfisher Properties (SW) Limited | Real estate | 2020 |
| Kingly Crafts Ltd | Wholesale & retail | 2025 |
| Kingpost Construction Limited | Construction | 2019 |
| Kingsbury Heating & Plumbing Ltd | Construction | 2016 |
| Kingsdown Farm (Management) Limited | Households | 2018 |
| Kingsdown Nurseries Holdings Limited | Financial services | 2023 |
| Kingsdown Nurseries Limited | Wholesale & retail | 2023 |
| Kingshill Court (Swindon) Management Company Limited | Households | 2001 |
| Kingshill Developments Limited | Extraterritorial | 1988 |
| Kingshill Remoulding Company Limited | Extraterritorial | 1968 |
| Kingsleigh Investments (Birmingham) Limited | Real estate | 1960 |
| Kingston British School of Rock LLP | | 2017 |
| Kingstown Limited | Information & communication | 2023 |
| Kinsey Premiere Services Ltd | Construction | 2010 |
| KIO Productions Limited | Other services | 1985 |
| Kioka Ltd | Real estate | 2026 |
| Kipawa Icon International Ltd | Professional & scientific | 2024 |