| JSC Parker Properties Ltd | Real estate | 2021 |
| JSD Carpentry Ltd | Construction | 2019 |
| JSD Solutions Ltd | Information & communication | 2024 |
| JSE Ltd | Wholesale & retail | 2020 |
| JSH Engineering Group EOT Limited | Financial services | 2022 |
| JSH Engineering Group Limited | Financial services | 2022 |
| JSH Trade Co Ltd | Professional & scientific | 2024 |
| Jshanel Childcare Ltd | Health & social care | 2024 |
| Jshl Property Ltd | Real estate | 2021 |
| JSI Property Limited | Construction | 2019 |
| JSJ Enterprise Ltd | Manufacturing | 2020 |
| JSK Automation Ltd | Manufacturing | 2024 |
| JSK Food Services Limited | Hospitality | 2011 |
| JSK Foods Limited | Hospitality | 2016 |
| JSK Roofing Ltd | Construction | 2025 |
| JSK Samy Ltd | Real estate | 2025 |
| JSK Ultrasonics Limited | Manufacturing | 2000 |
| JSP Home Ltd | Real estate | 2020 |
| JSP Interiors Limited | Construction | 2002 |
| Jspk Properties Ltd | Real estate | 2025 |
| JSR Dynamics Limited | Information & communication | 2016 |
| JSR Ventures Ltd | Real estate | 2024 |
| Jsrgb Limited | Arts & recreation | 2015 |
| JSW UK Trading Limited | Wholesale & retail | 2025 |
| JT & M Signs Ltd | Financial services | 2024 |
| JT & SSS Limited | Financial services | 2022 |
| JT &J Projects Ltd | Construction | 2024 |
| JT Coatings Ltd | Manufacturing | 2019 |
| JT Locksmiths Ltd | Manufacturing | 2025 |
| JT Operators Limited | Wholesale & retail | 2025 |
| JT Reinforcement Ltd | Construction | 2019 |
| JT Trading Ltd | Wholesale & retail | 2011 |
| Jtec Comms Limited | Information & communication | 2008 |
| Jtekt Sales UK Ltd | Transport & logistics | 1972 |
| JTP Property Holdings Ltd | Real estate | 2026 |
| Jtpb Ventures Ltd | Real estate | 2024 |
| JTT Garage Services Limited | Wholesale & retail | 2012 |
| Jubilee Supported Accommodation and Care (JSA) Limited | Health & social care | 2025 |
| Jubliee Healthcare Limited | Health & social care | 2023 |
| Judah Create Ltd | Arts & recreation | 2026 |
| Judah Recruitment & HR Solutions Limited | Administrative & support | 2025 |
| Judahdaniel Co. Ltd | Real estate | 2024 |
| Judd and Judd Limited | Information & communication | 2012 |
| Jude Marketing Limited | Professional & scientific | 2025 |
| Judes Properties Ltd | Real estate | 2025 |
| Judge Surveyors LLP | | 2020 |
| Judwaa Properties Ltd | Real estate | 2019 |
| Juggernaut Home Services Ltd | Real estate | 2025 |
| Juggernaut Trading Services Limited | Administrative & support | 2020 |
| Juhi Mishra Ltd | Health & social care | 2025 |
| Juicy Ventures Ltd | Wholesale & retail | 2026 |
| Jules MG Associates Limited | Professional & scientific | 2025 |
| Julia Charles Event Management Ltd | Other services | 2010 |
| Julian Ambrose LLP | | 2011 |
| Julian Joseph UK Limited | Wholesale & retail | 2016 |
| Julian Shreeve Limited | Professional & scientific | 2004 |
| Julie R England Consulting Limited | Wholesale & retail | 2015 |
| Julie’S Pastries Ltd | Hospitality | 2016 |
| Julius Blum UK Limited | Manufacturing | 2010 |
| JUM Holdings Limited | Professional & scientific | 2017 |
| Jumike Limited | Health & social care | 2020 |
| Jump Productions Limited | Arts & recreation | 2006 |
| Jump Space Limited | Arts & recreation | 2008 |
| JUN TAN Weddings Limited | Professional & scientific | 2022 |
| JUN XU Ltd. | Wholesale & retail | 2025 |
| JUN Yuan Penh Ltd. | Wholesale & retail | 2025 |
| Junckers Limited | Wholesale & retail | 1961 |
| Junction Electric Limited | Construction | 2018 |
| Juneninth Ltd | Public administration | 2018 |
| Jungheinrich Financial Services Limited | Financial services | 2006 |
| Jungheinrich Lift Truck Finance Limited | Financial services | 2006 |
| Jungheinrich UK Holdings Limited | Professional & scientific | 2001 |
| Jungheinrich UK Limited | Manufacturing | 1963 |
| Junior Consultancy Limited | Professional & scientific | 2011 |
| Juny Enterprise Limited | Health & social care | 2016 |
| Jupiter Hosting Limited | Information & communication | 2012 |
| JUR Scientific Ltd | Professional & scientific | 2023 |
| Juss Ltd | Other services | 2024 |
| Just a Enterprises Ltd | Administrative & support | 2019 |
| Just Beautie Limited | Wholesale & retail | 2019 |
| Just DO 72 Ltd. | Arts & recreation | 2025 |
| Just Epic Ltd | Arts & recreation | 2015 |
| Just Gents Limited | Other services | 1993 |
| Just Idlies Limited | Wholesale & retail | 2023 |
| Just Joy Care Ltd | Health & social care | 2022 |
| Just MG Solutions Limited | Wholesale & retail | 2025 |
| Just Pigs Limited | Extraterritorial | 2020 |
| Just Plumbing and Heating Limited | Construction | 2018 |
| Just Simply Change Ltd | Other services | 2019 |
| Just Snaxs by Ruties Ltd | Manufacturing | 2025 |
| Just Suppose Limited | Professional & scientific | 2005 |
| Just Trade - Export Guide Limited | Information & communication | 2017 |
| Just Website Ltd. | Information & communication | 2016 |
| Justnwao Healthcare Ltd | Health & social care | 2022 |
| Justthebusiness.Co.Uk Limited | Real estate | 2016 |
| JVK Properties Limited | Real estate | 2024 |
| JVL UK Limited | Manufacturing | 2004 |
| JVS Construction Ltd | Construction | 2026 |
| JVT Roofing & Cladding Services Ltd | Other services | 2016 |
| JW Exports Limited | Wholesale & retail | 2018 |