| John BLU Limited | Other services | 2026 |
| John Gower Limited | Manufacturing | 2014 |
| John Grose Group Limited | Wholesale & retail | 1980 |
| Johnson Offshore Services Limited | Professional & scientific | 2013 |
| Jojos Lowestoft Ltd | Hospitality | 2017 |
| JON Nichols Plumbing and Heating Limited | Construction | 2011 |
| Jonathan COE (Ace Accountants) Ltd | Professional & scientific | 2000 |
| Joshua Day Limited | Professional & scientific | 2016 |
| Jpgeo Ltd | Professional & scientific | 2022 |
| JRH Industry & General Services Ltd | Professional & scientific | 2017 |
| JRW Electrical Limited | Construction | 2017 |
| JS Inspection Ltd | Professional & scientific | 2008 |
| JSB Marketing Limited | Wholesale & retail | 2026 |
| JTB Investments Limited | Real estate | 2017 |
| Jubaifu Limited | Hospitality | 2019 |
| Juiced Media Limited | Information & communication | 2009 |
| Julian D Hood Limited | Construction | 2015 |
| JUS’ Winging IT POP UPS Ltd | Hospitality | 2025 |
| JVT Properties Limited | Extraterritorial | 2005 |
| JWB Property Management Limited | Real estate | 2017 |
| K & S Fish Limited | Real estate | 2009 |
| K B Stannard & Sons Limited | Wholesale & retail | 2004 |
| K P Sanders Limited | Construction | 2016 |
| K&B Properties (GY) Ltd | Real estate | 2025 |
| K. Holdings (East Anglia) Limited | Construction | 1981 |
| Kafamdu Limited | Hospitality | 2020 |
| KAG Wiring Services Limited | Energy | 2014 |
| KAM Consultancy Services Limited | Professional & scientific | 2025 |
| Kamar Group Limited | Real estate | 2015 |
| Kamaya Hosting Ltd | Information & communication | 2021 |
| Kandu Property Maintenance Limited | Construction | 2022 |
| Kangift Limited | Information & communication | 2014 |
| KAP Kreations Ltd | Construction | 2025 |
| Karan Convenience Store Ltd | Wholesale & retail | 2026 |
| Karen Carson Limited | Health & social care | 2002 |
| Karl Mcgee Limited | Wholesale & retail | 2025 |
| Karl Sparky Ltd | Construction | 2025 |
| Karol Fengler Ltd | Health & social care | 2021 |
| Karpet Kingdom (Holdings) Limited | Financial services | 2016 |
| Karpet Kingdom Limited | Wholesale & retail | 1984 |
| Kaytix Ltd | Wholesale & retail | 2025 |
| KB Computers Ltd | Wholesale & retail | 2016 |
| Kb-Energy APS UK Limited | Administrative & support | 2024 |
| KBA Media Ltd | Wholesale & retail | 2009 |
| KCH (UK) Holdings Limited | Health & social care | 2014 |
| KCP Aviation Consultancy Ltd | Professional & scientific | 2022 |
| KCS Catering Ltd | Hospitality | 2025 |
| KDN Developments Ltd Limited | Real estate | 2025 |
| KE Property Limited | Real estate | 2023 |
| Keable & Flowers Limited | Hospitality | 2003 |
| Keano White Limited | Arts & recreation | 2024 |
| Keith Lindoff Limited | Other services | 2010 |
| Kelly Pain Court Management Limited | Professional & scientific | 2002 |
| Kenny Renewables Limited | Professional & scientific | 2023 |
| Kenny's Barber Shop Limited | Other services | 2002 |
| Kenting Drilling Services Limited | Wholesale & retail | 1975 |
| Kerr-Plunkett Properties Limited | Real estate | 2021 |
| Kerrys Mini Market Limited | Wholesale & retail | 2017 |
| Kessingland Kabs Limited | Other services | 2003 |
| Kessingland Limited | Administrative & support | 2025 |
| Kessingland Village Fryer Limited | Wholesale & retail | 2023 |
| Kestrel Properties (Waveney) Limited | Real estate | 2020 |
| Kestryl Healthcare Ltd | Health & social care | 2021 |
| Ketters Properties Ltd | Real estate | 2024 |
| Kevin Barber Cladding Limited | Construction | 2014 |
| Kewzone Management Limited | Professional & scientific | 2005 |
| Key Locum Solutions Ltd | Health & social care | 2011 |
| Keystone Contractors Limited | Construction | 2014 |
| KG Executive Pet Transport Limited | Transport & logistics | 2023 |
| KH Investments (Holt) Limited | Health & social care | 2026 |
| Khazman Bullion Limited | Manufacturing | 2026 |
| Kidderminster 247 Ltd | Arts & recreation | 2022 |
| Kids Zone Childcare Limited | Education | 2014 |
| Kidzfest Limited | Hospitality | 2022 |
| Kilic Investment and Renovation Ltd | Real estate | 2024 |
| Kimberley Consultancy Ltd | Professional & scientific | 2019 |
| KIN9 Property Limited | Real estate | 2022 |
| Kinahan Accounting Services Ltd | Professional & scientific | 2005 |
| Kingfisher Modular Homes Limited | Construction | 2021 |
| Kings Autos Ltd | Wholesale & retail | 2023 |
| Kingsley (FVL) Development Limited | Construction | 2021 |
| Kingsley (FVL) Property Limited | Health & social care | 2021 |
| Kingsley (KMT) Limited | Real estate | 2020 |
| Kingsley Buckingham Lodge Limited | Real estate | 2020 |
| Kingsley Care Homes Limited | Health & social care | 2002 |
| Kingsley Care Limited | Health & social care | 2026 |
| Kingsley Care Services Limited | Health & social care | 2026 |
| Kingsley Foundation | Health & social care | 2020 |
| Kingsley Healthcare (Birmingham) Limited | Health & social care | 2022 |
| Kingsley Healthcare (BL) Limited | Health & social care | 2018 |
| Kingsley Healthcare (Bournemouth Property) Limited | Financial services | 2016 |
| Kingsley Healthcare (Bournemouth) Limited | Health & social care | 2016 |
| Kingsley Healthcare (Brackley) Limited | Health & social care | 2016 |
| Kingsley Healthcare (Caledonia) Limited | Health & social care | 2009 |
| Kingsley Healthcare (DS) Limited | Financial services | 2015 |
| Kingsley Healthcare (Formby) Limited | Health & social care | 2025 |
| Kingsley Healthcare (Holt) Limited | Health & social care | 2021 |
| Kingsley Healthcare (Kessingland) Limited | Health & social care | 2025 |
| Kingsley Healthcare (LH) Property Limited | Health & social care | 2026 |
| Kingsley Healthcare (OLH) Limited | Financial services | 2018 |