| Jerb Ltd | Information & communication | 2024 |
| Jeremy Hart Limited | Professional & scientific | 2017 |
| Jerry's Ventures Ltd | Transport & logistics | 2024 |
| Jerzy Services Limited | Transport & logistics | 2009 |
| Jeshil Infotek Limited | Information & communication | 2025 |
| Jessica Banton Hair Ltd | Other services | 2022 |
| JET Wash Inovations Ltd | Administrative & support | 2023 |
| Jetpatcher Corporation Limited | Manufacturing | 2016 |
| Jett Lets Ltd | Real estate | 2021 |
| Jetzen Limited | Extraterritorial | 2011 |
| Jfdi Ltd | Households | 2025 |
| JFI Europe Ltd | Professional & scientific | 2022 |
| Jfnl Services Ltd | Transport & logistics | 2025 |
| JG Engineering Limited | Professional & scientific | 2023 |
| JG Mailing Limited | Other services | 2019 |
| JG Property Partners Limited | Real estate | 2024 |
| JGF Law Ltd | Professional & scientific | 2022 |
| JGP Civils Limited | Construction | 2015 |
| JH Design Ltd | Professional & scientific | 2026 |
| Jhallis Healthcare Limited | Health & social care | 2024 |
| JHK Properties Ltd | Other services | 2016 |
| Jhon Trans Limited | Transport & logistics | 2024 |
| JHR Change Management Limited | Professional & scientific | 2011 |
| Jiggery Pokery Embroidery Kits Limited | Wholesale & retail | 2014 |
| Jimmy Beam Downlights Limited | Wholesale & retail | 2012 |
| JIN Saini Ltd | Information & communication | 2017 |
| Jirox Limited | Wholesale & retail | 2024 |
| Jitcnc Ltd. | Professional & scientific | 2017 |
| JJ Best Properties Ltd | Real estate | 2024 |
| JJ Tours & Travels Ltd | Transport & logistics | 2025 |
| Jjas Holdings Ltd | Real estate | 2020 |
| JJM Holdco Limited | Financial services | 2026 |
| JJT Civils Limited | Construction | 2016 |
| JK Mazur Ltd | Transport & logistics | 2010 |
| JK Timber Limited | Wholesale & retail | 2015 |
| Jkaj Ltd | Administrative & support | 2025 |
| JKB Cosmetics Limited | Extraterritorial | 2014 |
| JKN Recovery Limited | Wholesale & retail | 2020 |
| JL Carrier Mrcvs Limited | Professional & scientific | 2025 |
| JLN Vehicle Movements Ltd | Transport & logistics | 2022 |
| JLO Logistics Ltd | Transport & logistics | 2024 |
| JM Driving Services Ltd | Transport & logistics | 2009 |
| JM Tree Doctors Ltd | Agriculture & fishing | 2025 |
| JMA Hotels Ltd | Real estate | 2025 |
| Jmap Enterprises Ltd | Real estate | 2019 |
| JMB Homes Ltd | Construction | 2017 |
| JMC Controls Ltd | Professional & scientific | 2023 |
| JMD Roofing Specialist Limited | Construction | 2014 |
| JMG Fencing Contractors Limited | Construction | 2011 |
| JMJ Tech Ltd | Other services | 2018 |
| JN Stay DRY Limited | Construction | 2026 |
| JOB LOT Building Materials Ltd | Wholesale & retail | 2025 |
| Jobby Limited | Other services | 2017 |
| Jobling Road Surfacing Ltd | Construction | 2025 |
| Jobsbody Limited | Administrative & support | 2011 |
| Jockey Transport Ltd | Transport & logistics | 2014 |
| John Good Limited | Manufacturing | 1989 |
| John Jakob Ltd | Transport & logistics | 2024 |
| John Shelton Burial Services Ltd | Other services | 2016 |
| John Shepherd and Vaughan Limited | Real estate | 2011 |
| John Whitaker the Legend Ltd | Wholesale & retail | 2024 |
| Johns Gilbert & Frankton LLP | | 2013 |
| Johnsons Building Services and Maintenance Ltd | Construction | 2023 |
| Johnsons Hire Limited | Administrative & support | 2023 |
| Johnsons Plumbing Ltd | Construction | 2020 |
| Johnty M Ltd | Information & communication | 2026 |
| Jojo Rugby Limited | Other services | 2015 |
| Joliromi | Financial services | 2019 |
| Jolodo Ltd | Hospitality | 2022 |
| Jones Mortgages & Investments Ltd. | Financial services | 2015 |
| Jony Transport Ltd | Transport & logistics | 2023 |
| Joseph Arthur Consulting Limited | Administrative & support | 2025 |
| Joseph Arthur Holdings Ltd | Real estate | 2025 |
| Joseph Arthur Properties Limited | Administrative & support | 2023 |
| Joshi Accounting Services Limited | Professional & scientific | 2011 |
| Joshua Graham Ltd | Other services | 2017 |
| Jozef Fedor Limited | Construction | 2010 |
| Jpaczek Ltd | Transport & logistics | 2020 |
| JPH UK Consultancy Limited | Professional & scientific | 2024 |
| JPK Private Limited | Wholesale & retail | 2025 |
| JPP Transport Ltd | Transport & logistics | 2021 |
| JR Metals Ltd | Water & waste | 2023 |
| JRD Property Ltd | Real estate | 2022 |
| JRM Quality Engineering Ltd | Information & communication | 2013 |
| JRP Electrical Services Limited | Construction | 2011 |
| JSA Commercial Decorators Ltd. | Construction | 2016 |
| JSA Decorators Ltd | Construction | 2026 |
| JSA Express Limited | Transport & logistics | 2026 |
| JSB Fire & Security Limited | Administrative & support | 2012 |
| JSB Rugby Ltd | Wholesale & retail | 2024 |
| Jsbbsa Limited | Wholesale & retail | 2019 |
| JSL Healthcare Ltd | Health & social care | 2024 |
| JSP Engineering Solutions Ltd | Manufacturing | 2023 |
| JSP Property Services Ltd | Administrative & support | 2026 |
| JSR Leisure Ltd | Hospitality | 2021 |
| Jsrk Trading Ltd | Financial services | 2025 |
| Jsrugby Ltd | Hospitality | 2023 |
| JSV (London) Ltd | Health & social care | 2017 |
| JSW Brands Limited | Wholesale & retail | 2026 |
| JTA Pro Ltd | Real estate | 2021 |