| JT Langley Ltd | Professional & scientific | 2026 |
| JT Ward Kitchens & Bedrooms Limited | Manufacturing | 2013 |
| JTN Transport Ltd | Transport & logistics | 2021 |
| JTS Landscapes & Paving Ltd | Construction | 2021 |
| Juicy Dreams Ltd | Wholesale & retail | 2020 |
| Julianfl Limited | Transport & logistics | 2015 |
| Julius.J Transport Ltd | Transport & logistics | 2021 |
| Jusjam Ltd | Manufacturing | 2025 |
| Just 4 Kids Limited | Transport & logistics | 2018 |
| Just Chilling Haulage Ltd | Transport & logistics | 2022 |
| Just Contract Furniture Limited | Other services | 2019 |
| Just OIL Services Limited | Construction | 2025 |
| Just Optics Limited | Wholesale & retail | 2023 |
| Just Property Care Ltd | Construction | 2020 |
| Just to SEE YOU Smile Ltd | Wholesale & retail | 2023 |
| Just-Ice Consultants Ltd | Professional & scientific | 2025 |
| Justin Case Management Ltd | Real estate | 2025 |
| Justomus Ltd | Transport & logistics | 2015 |
| JVG Fresh Limited | Wholesale & retail | 2014 |
| JW Roofline Home Improvements Ltd | Construction | 2025 |
| JW Vehicle Repairs Ltd | Wholesale & retail | 2025 |
| JWD Contracting Ltd | Construction | 2024 |
| JWD Holdings Limited | Financial services | 2022 |
| JWK Electrical (Lincs) Ltd | Construction | 2017 |
| JZ Trans Ltd | Transport & logistics | 2014 |
| K & D Appliance Services Ltd | Wholesale & retail | 2012 |
| K & K Windows Limited | Construction | 2009 |
| K and M Flowers Ltd | Wholesale & retail | 2024 |
| K C Equipment Sales Ltd | Wholesale & retail | 2018 |
| K D H Projects Limited | Construction | 2005 |
| K D N Contracting Ltd | Construction | 2012 |
| K Grace Limited | Health & social care | 2025 |
| K J C Property Limited | Real estate | 2017 |
| K Kuba Ltd | Transport & logistics | 2026 |
| K Martin & SON Limited | Agriculture & fishing | 2003 |
| K Pick Holdings Limited | Financial services | 2013 |
| K Pick Property Services Limited | Real estate | 2018 |
| K Putterill Farms Limited | Agriculture & fishing | 2013 |
| K R Professional Driving Limited | Transport & logistics | 2022 |
| K Reedman Polytunnels Ltd | Construction | 2024 |
| K REG Engineering Ltd | Professional & scientific | 2026 |
| K W Naylor and SON (Holdings) Limited | Financial services | 2015 |
| K&J Recruitment Ltd | Administrative & support | 2021 |
| K&L Services Limited | Manufacturing | 2023 |
| K.A. Goulden Electrical Limited | Administrative & support | 2003 |
| K.M Carpentry Woodworx Ltd | Construction | 2023 |
| K.N.Bunn Europe Limited | Administrative & support | 2000 |
| K.P.K Transport Limited | Administrative & support | 2014 |
| K24 Fit Ltd | Other services | 2026 |
| Kabanek 78 Ltd | Transport & logistics | 2018 |
| Kabin Designs Ltd | Professional & scientific | 2023 |
| Kai's Restaurant and Bar Ltd | Hospitality | 2026 |
| KAK Group Services Limited | Households | 2026 |
| Kalahari Ltd | Wholesale & retail | 2024 |
| Kaldom Limited | Transport & logistics | 2019 |
| Kamad Transport Ltd | Transport & logistics | 2025 |
| Kamaje Holding Ltd | Financial services | 2025 |
| Kamil Grochowski Transport Ltd | Transport & logistics | 2019 |
| Kamt Ltd | Transport & logistics | 2018 |
| Kangaroo Transporter Ltd | Transport & logistics | 2026 |
| Karella Events Limited | Administrative & support | 2024 |
| Karma Ltd | Transport & logistics | 2024 |
| Karmon Innovations Limited | Information & communication | 2018 |
| Karocolin Limited | Agriculture & fishing | 2018 |
| Karsa Limited | Wholesale & retail | 2005 |
| Karsten UK Limited | Agriculture & fishing | 2003 |
| Kart Parts UK Ltd | Administrative & support | 2013 |
| Karting Supplies Limited | Administrative & support | 1999 |
| Katana an Ltd | Hospitality | 2018 |
| Katerina Transport Ltd | Transport & logistics | 2024 |
| Kathryn Vincent Consultancy Services Ltd | Professional & scientific | 2025 |
| KB Roofing (Norfolk) Ltd | Construction | 2023 |
| KBT632 Limited | Transport & logistics | 2025 |
| Kcmets Ltd | Health & social care | 2025 |
| Kcsuk Ltd | Construction | 2020 |
| KDI Innovations Ltd | Transport & logistics | 2024 |
| Keconcrete Ltd | Construction | 2022 |
| Keepsake Cassette Ltd | Information & communication | 2025 |
| Keepstem Limited | Financial services | 1997 |
| Keith Bunn Haulage Limited | Transport & logistics | 2004 |
| Keith Hall & SON Ltd | Agriculture & fishing | 2025 |
| Keiths Mechanical Services Ltd | Manufacturing | 2018 |
| Kelfreight Ltd | Transport & logistics | 2015 |
| Kelleras Ltd | Transport & logistics | 2021 |
| Kelmore Holdings Ltd | Financial services | 2026 |
| Kemmy Limited | Health & social care | 2020 |
| Kentro Films Limited | Information & communication | 2021 |
| Kenzo Homes Limited | Construction | 2025 |
| Kepax One Trans Ltd | Transport & logistics | 2015 |
| Kerry Property Maintenance Ltd | Manufacturing | 2011 |
| Keston Fields Limited | Construction | 2018 |
| Keston Fields MGT Company Ltd | Real estate | 2021 |
| Kettering Roofing Solutions (JD) Ltd | Construction | 2026 |
| KEVIN2019 Ltd | Transport & logistics | 2023 |
| Kevmil Spedition Ltd | Transport & logistics | 2016 |
| Kevtrans Ltd | Transport & logistics | 2025 |
| Key Right Ltd | Wholesale & retail | 2020 |
| Keylo Construction Ltd | Construction | 2025 |
| KF Real Estate Partners Ltd | Real estate | 2023 |
| KGS Electrical Ltd | Construction | 2010 |