| JP IT Consulting Limited | Information & communication | 2020 |
| JP Mechanical and GAS Engineering Limited | Construction | 2025 |
| JPC Consulting Solutions Ltd | Information & communication | 2023 |
| JPG Contrast UK Limited | Professional & scientific | 2008 |
| JPH Accountancy Services Limited | Professional & scientific | 2019 |
| JPH Consulting Services Limited | Professional & scientific | 2026 |
| JPK Healthcare Ltd | Health & social care | 2023 |
| JPM Driveways Ltd | Construction | 2022 |
| JPT Construction & Building Limited | Construction | 2022 |
| JPW Electrical Contractors Limited | Construction | 2022 |
| JR Andrews Building Limited | Construction | 2025 |
| JR Cars and Vans Limited | Wholesale & retail | 2025 |
| JR Junior Limited | Transport & logistics | 2023 |
| JRC Electrical South East Ltd | Construction | 2019 |
| Jrgv Holdings Ltd | Financial services | 2025 |
| JRM Build Ltd | Construction | 2025 |
| JS Bulamino Ltd | Wholesale & retail | 2023 |
| JS Solutions (U.K) Limited | Professional & scientific | 2018 |
| JS Tool Fitters Limited | Other services | 2025 |
| JSM Investments Limited | Administrative & support | 2016 |
| JSP Services Limited | Wholesale & retail | 2010 |
| JSW Upholstery Ltd | Other services | 2019 |
| JT Security Products Ltd | Manufacturing | 2013 |
| Jt&T Real Estate Ltd. | Financial services | 2013 |
| JTA Property Investments Limited | Real estate | 2023 |
| JTD Engineering Services Ltd | Wholesale & retail | 2015 |
| JTK Healthcare Solution Limited | Health & social care | 2023 |
| JTR Amazon Distributions Limited | Wholesale & retail | 2026 |
| JTR Prop Trading Limited | Professional & scientific | 2026 |
| Julian Bell Consulting Limited | Professional & scientific | 2022 |
| Julie KIM Photography Ltd | Professional & scientific | 2011 |
| Julietj Healthcare Services Ltd | Health & social care | 2022 |
| Jullio SPR Ltd | Construction | 2010 |
| Jumks Concierge Services Limited | Hospitality | 2021 |
| Jummysum Limited | Administrative & support | 2011 |
| Jungle Jive Music Limited | Arts & recreation | 2025 |
| Junkyard Jukebox Ltd | Manufacturing | 2018 |
| Juno Management Services Limited | Administrative & support | 2017 |
| Juno Meadway Limited | Other services | 2020 |
| Juno Solutions Limited | Administrative & support | 2011 |
| Juozas Carpentry Ltd | Manufacturing | 2019 |
| Jupiter Admin Services Limited | Administrative & support | 2013 |
| Jupiter Prestige Group Europe Limited | Administrative & support | 2003 |
| Jupiter Prestige Group Holdings Limited | Administrative & support | 2012 |
| Jupiter TV and Security Limited | Administrative & support | 2025 |
| Jurista Solutions Ltd | Professional & scientific | 2025 |
| Just BIN Cleaned Limited | Administrative & support | 2023 |
| Just General Insurance Limited | Households | 2008 |
| Just Interior Ltd | Real estate | 2019 |
| Just Jerk Ltd | Hospitality | 2025 |
| Justmyexcel Care Ltd | Health & social care | 2022 |
| Justreallygoodvibes Ltd | Wholesale & retail | 2024 |
| JV Technokids Club UK Ltd | Education | 2023 |
| JVG Real Estate Limited | Real estate | 2024 |
| JVH Building & Construction Ltd | Construction | 2022 |
| JVH Heating Ltd | Construction | 2021 |
| JWB Ministry Assistance Limited | Administrative & support | 2020 |
| JWW Group UK Ltd | Real estate | 2025 |
| JXM Collectibles Limited | Wholesale & retail | 2025 |
| JY Carpentry and Building Ltd | Construction | 2025 |
| Jyheda Limited | Wholesale & retail | 2021 |
| Jzion Ltd | Health & social care | 2022 |
| K & D Developments Limited | Real estate | 2009 |
| K & J Contractors Limited | Construction | 2021 |
| K & J Smart Repair Ltd | Wholesale & retail | 2022 |
| K & K Sisters Vehicle Repairs Ltd | Wholesale & retail | 2020 |
| K & M Asante Enterprise Ltd | Real estate | 2026 |
| K & M Property Developments Ltd | Construction | 2024 |
| K & N Group Limited | Extraterritorial | 2011 |
| K C (Essex) Limited | Other services | 2025 |
| K C Design & Development Ltd | Other services | 2016 |
| K Dickinson Ltd | Construction | 2025 |
| K N K Limited | Wholesale & retail | 2026 |
| K Williamson Construction Limited | Construction | 2013 |
| K&D Facades Ltd | Construction | 2023 |
| K&R Flooring Limited | Construction | 2026 |
| K&R Motors Cars Ltd | Wholesale & retail | 2020 |
| K&R Primecare Ltd | Health & social care | 2025 |
| K-Electrical Testing Ltd | Construction | 2019 |
| K-Value Consulting Limited | Information & communication | 2025 |
| K50 Academy Limited | Other services | 2020 |
| K7 Group Ltd | Wholesale & retail | 2026 |
| K9 Dazy Ltd | Administrative & support | 2020 |
| KA Inspections Ltd | Other services | 2023 |
| Kaboodl Ltd | Information & communication | 2022 |
| KAD Consultants Limited | Administrative & support | 2011 |
| Kade Plastering Ltd | Construction | 2025 |
| Kaizen Business Consultancy Limited | Administrative & support | 2012 |
| Kajobeth Limited | Real estate | 2025 |
| Kaka Constructions Ltd | Construction | 2025 |
| Kalekim Decor Limited | Construction | 2025 |
| Kallima Limited | Wholesale & retail | 2025 |
| Kalm Creative Ltd | Information & communication | 2018 |
| Kalm Productions Ltd | Manufacturing | 2022 |
| Kalpana Properties Ltd | Real estate | 2024 |
| Kalyanpavan Ltd | Hospitality | 2026 |
| KAM Automotive Ltd | Wholesale & retail | 2016 |
| KAM118 Family Properties Ltd | Real estate | 2019 |
| Kamalam Ltd | Administrative & support | 2023 |
| Kamaru Property Limited | Real estate | 2020 |