| Jargon Group Ltd | Professional & scientific | 2022 |
| Jason Wall Project Management Limited | Construction | 2012 |
| Javre DOW Limited | Administrative & support | 2022 |
| JBB Property Limited | Real estate | 2019 |
| JC Storage Ltd | Wholesale & retail | 2020 |
| Jc&C Bowers Holdings Ltd. | Wholesale & retail | 2015 |
| Jcdc Structural Engineering Ltd | Construction | 2024 |
| JD Biopharma Consulting Limited | Professional & scientific | 2024 |
| Jemms Property Limited | Real estate | 2022 |
| Jennal Consultancy Ltd | Professional & scientific | 2024 |
| Jet-Care International Limited | Professional & scientific | 1982 |
| Jeto Limited | Construction | 2003 |
| JFF Consulting Services Ltd | Professional & scientific | 2025 |
| Jibbs Meadow Management Company Limited | Real estate | 2010 |
| Jigsaw Land and Developments Limited | Construction | 2017 |
| JJ Automotive Solutions Ltd | Wholesale & retail | 2024 |
| Jjap Limited | Professional & scientific | 2013 |
| JJK Real Estate Ltd | Real estate | 2018 |
| JJR Tiling Limited | Construction | 2023 |
| JKL Architecture Ltd | Administrative & support | 2010 |
| JL Machinery Services Limited | Manufacturing | 2026 |
| JLD Associates Limited | Professional & scientific | 2013 |
| JLH Accountancy and Bookkeeping Ltd | Professional & scientific | 2019 |
| JMC Restore Ltd | Real estate | 2024 |
| JMH Recruit & Consult Limited | Administrative & support | 2024 |
| JMR Services (UK) Limited | Construction | 2012 |
| JNP Contracting Limited | Construction | 2023 |
| John Mcguinness Project Management Limited | Construction | 2012 |
| John Searle Funfairs Limited | Arts & recreation | 2008 |
| Jollybee Holdings Limited | Real estate | 2018 |
| JON Cooke Physiotherapy Limited | Health & social care | 2014 |
| Jones-Parry Associates Limited | Professional & scientific | 2013 |
| JP Pheonix Ltd | Financial services | 2025 |
| JPS Farming Holdings Limited | Financial services | 2018 |
| JRB Network Ltd | Professional & scientific | 2012 |
| JRM Homes Ltd | Real estate | 2018 |
| Js&Ic Ltd | Professional & scientific | 2023 |
| JSA Landscape Group Limited | Administrative & support | 2012 |
| JSA Utilities Limited | Extraterritorial | 2012 |
| JSB UK Properties Ltd | Real estate | 2024 |
| Jstreamnet Limited | Information & communication | 2015 |
| Jupiter QA Consultancy Limited | Professional & scientific | 2024 |
| Jupp Castle Financial Services Limited | Administrative & support | 2004 |
| Jupp Castle Limited | Professional & scientific | 2002 |
| Just Good Science Ltd | Education | 2022 |
| Just Kampers (Holdings) Limited | Administrative & support | 2009 |
| Just Kampers Limited | Wholesale & retail | 1995 |
| Just Love Studio Ltd | Wholesale & retail | 2021 |
| JV Agri & Equine Services Ltd | Agriculture & fishing | 2025 |
| JV Risk Consulting Limited | Professional & scientific | 2024 |
| JVY Limited | Wholesale & retail | 2010 |
| Jwsa 2 Limited | Professional & scientific | 2015 |
| K & J Farms Limited | Agriculture & fishing | 2021 |
| K Steele Associates Limited | Hospitality | 2016 |
| K3 Mart Limited | Wholesale & retail | 2014 |
| Kaba Pulse and Earthworks Solutions Limited | Construction | 2025 |
| Kaidan Limited | Information & communication | 2015 |
| Kaizen Market Ltd | Wholesale & retail | 2022 |
| Kalai Kaviri Collegiate Arts | Education | 2005 |
| Kalnet Ltd. | Information & communication | 2021 |
| Katara Limited | Education | 2002 |
| Kate Wellesley Ltd | Professional & scientific | 2025 |
| Katie Wildsmith Limited | Other services | 2015 |
| Kellway Limited | Real estate | 2021 |
| Kelly (Builders) Ltd | Construction | 1988 |
| Kelly (Properties) Limited | Real estate | 1947 |
| KEW West Limited | Real estate | 1995 |
| Keystone OPS Ltd | Information & communication | 2025 |
| Keystroke Pro Limited | Administrative & support | 2001 |
| Kilnabrack Services Limited | Professional & scientific | 2022 |
| KIM Chapman PA Services Limited | Public administration | 2013 |
| Kinetic Racing & Engineering Ltd | Arts & recreation | 2026 |
| King Partners Limited | Wholesale & retail | 2023 |
| Kings Mews (North Warnborough) M.C. Limited | Administrative & support | 1994 |
| Kingsbridge Copse Management Company Limited | Households | 1994 |
| Kingston House (Odiham) Management Limited | Households | 1994 |
| Kingsway Asset Management Ltd | Professional & scientific | 2010 |
| Kingswell Private Office Ltd | Professional & scientific | 2026 |
| Kinolibrary Group Holdings Limited | Financial services | 2020 |
| Kinolibrary Ltd | Arts & recreation | 2011 |
| Kinolibrary Rights Limited | Professional & scientific | 2020 |
| Kins Mckay Property Ltd | Real estate | 2025 |
| Kistler Fiber Technology Ltd | Manufacturing | 2022 |
| Kistler Instruments Limited | Manufacturing | 1973 |
| Kjbn Consultants Ltd | Construction | 2025 |
| KJS Savage Limited | Administrative & support | 2024 |
| KK Daytona Holding Ltd | Financial services | 2016 |
| KMC Cleaning Limited | Administrative & support | 2009 |
| KMF Trading Ltd | Other services | 2025 |
| KOA Media Limited | Professional & scientific | 2013 |
| Kooling Robots Limited | Information & communication | 2020 |
| Kopros Limited | Agriculture & fishing | 1993 |
| KPC Creative Communication Ltd. | Professional & scientific | 2005 |
| Kraken Print & Design Ltd | Manufacturing | 2014 |
| KRE8 Designs Ltd | Information & communication | 2011 |
| Krjl Ltd | Financial services | 2023 |
| KTY. Ltd | Information & communication | 2020 |
| Kwikbolt Limited | Manufacturing | 2011 |
| Kwikguides Limited | Information & communication | 2004 |
| KWP Services Ltd | Professional & scientific | 2019 |