| John F. Hunt Formwork Limited | Construction | 2003 |
| John F. Hunt Hire Centres Ltd | Administrative & support | 1994 |
| John F. Hunt Management Company Limited | Administrative & support | 1999 |
| John F. Hunt Plant Hire Ltd | Construction | 1986 |
| John V Ltd | Agriculture & fishing | 2021 |
| Johnson Trans Ltd | Transport & logistics | 2016 |
| Johnson Wohnson Limited | Wholesale & retail | 2022 |
| Joive Ltd | Financial services | 2022 |
| Jojela Property Consult Limited | Real estate | 2020 |
| Jojo's Drinks Company Ltd | Manufacturing | 2023 |
| Jola-Olu Limited | Health & social care | 2013 |
| Jolieskin Ltd | Wholesale & retail | 2022 |
| Jolly Care Limited | Administrative & support | 2021 |
| Jollyk Care Services Limited | Hospitality | 2023 |
| Jolsta Ltd | Transport & logistics | 2018 |
| Jomich Ltd | Administrative & support | 2014 |
| Jonshi Limited | Health & social care | 2020 |
| Jordan Francis Ltd | Administrative & support | 2025 |
| Joriella Properties Limited | Real estate | 2020 |
| Josana Havens Care Services Ltd | Health & social care | 2026 |
| Joseph Property Investment Group Ltd | Households | 2019 |
| Josephine Care Limited | Administrative & support | 2022 |
| Joses Comfort Ltd | Other services | 2018 |
| Josh Autos Ltd | Wholesale & retail | 2020 |
| Josiah Cornell Ltd | Real estate | 2026 |
| Jostem Consulting Limited | Other services | 2014 |
| Jotrans Ltd | Transport & logistics | 2019 |
| Journer Ltd | Administrative & support | 2025 |
| Jowal Project (UK) Limited | Information & communication | 2008 |
| Jowonders Bright & Clean Ltd | Wholesale & retail | 2024 |
| Joy of Bespoke Ltd | Wholesale & retail | 2021 |
| JP & T Properties Ltd | Real estate | 2022 |
| JP Events Consultants Ltd | Administrative & support | 2024 |
| JP Hire Solutions Limited | Administrative & support | 2024 |
| Jpcstore Ltd | Wholesale & retail | 2021 |
| Jpms Property Maintenance Services Ltd | Administrative & support | 2026 |
| JR & HCL Chapman Properties Limited | Real estate | 2009 |
| JR Power Investment Limited | Real estate | 2017 |
| JRE Demolition & Waste Ltd | Construction | 2019 |
| JRJ Capital Ltd | Real estate | 2022 |
| JRK Trans Ltd | Transport & logistics | 2023 |
| JRK Ukbd Ltd | Wholesale & retail | 2018 |
| JRM Prosperity Ltd | Real estate | 2020 |
| JRT Group Solutions Limited | Health & social care | 2023 |
| JS Financial Consultants Limited | Financial services | 1999 |
| Jsa&Co. Ltd | Administrative & support | 2026 |
| JSC Heloise Healthcare Limited | Health & social care | 2014 |
| Jsfd Limited | Real estate | 2024 |
| JSI Timber Products Ltd | Wholesale & retail | 2017 |
| JSR Haulage Ltd | Transport & logistics | 2010 |
| JT Bathroom and Design Ltd | Construction | 2025 |
| JT Williams Ltd | Professional & scientific | 2017 |
| Jtcan Ltd | Information & communication | 2014 |
| Jucan Solutions Ltd | Transport & logistics | 2015 |
| Judy Tech Ltd | Professional & scientific | 2023 |
| JUL Deals Limited | Wholesale & retail | 2025 |
| Julakan Limited | Professional & scientific | 2021 |
| Julia KAY (UK) Ltd | Health & social care | 2018 |
| Julia&Co Ltd | Transport & logistics | 2024 |
| JULIESKITCHEN612 Ltd | Hospitality | 2025 |
| Juliseg Limited | Health & social care | 2023 |
| Jumbola Foods Limited | Hospitality | 2025 |
| Jungle Market Ltd | Wholesale & retail | 2022 |
| Jupiter Construction Services Group Limited | Construction | 2026 |
| Jurys Civil Engineering Ltd | Construction | 2016 |
| Just Haat Limited | Wholesale & retail | 2017 |
| Just Live Limited | Wholesale & retail | 2008 |
| Just Move Electrical Maintenance Ltd | Manufacturing | 2025 |
| Just Move Plumbing & Heating Ltd | Construction | 2025 |
| Just Move Property Maintenance Ltd | Real estate | 2025 |
| Just Swap My Engine Ltd | Wholesale & retail | 2025 |
| Justgotrans Ltd | Transport & logistics | 2026 |
| Justin Cayle Investments Ltd | Real estate | 2022 |
| Justjojo Distro Ltd | Information & communication | 2020 |
| Justjojo Entertainment Limited | Information & communication | 2015 |
| Jutland Properties Limited | Construction | 1969 |
| Juwayriah Online Store Limited | Wholesale & retail | 2025 |
| JVM Sellers Ltd | Wholesale & retail | 2026 |
| Jvpi Ltd | Construction | 2019 |
| JW Craft Ltd | Wholesale & retail | 2025 |
| JWL Waste Management Ltd | Water & waste | 2023 |
| JY Aesthetics Limited | Health & social care | 2024 |
| J’Adore Shutters Ltd | Wholesale & retail | 2025 |
| J’S Cleaning Ltd | Administrative & support | 2020 |
| K & a Works Limited | Wholesale & retail | 2012 |
| K a Lucky Homes Ltd | Construction | 2024 |
| K B Brickwork & Building Services Ltd | Construction | 2025 |
| K Brett Engineering Limited | Wholesale & retail | 2013 |
| K Cart Ltd | Wholesale & retail | 2023 |
| K G Auto and SON Limited | Wholesale & retail | 2016 |
| K L S Scaffolding Limited | Construction | 2015 |
| K S E Property Ltd | Real estate | 2025 |
| K Security Ltd | Administrative & support | 2023 |
| K Squared Films Ltd | Information & communication | 2018 |
| K T American Nails Limited | Other services | 2007 |
| K&J Energy Ltd | Professional & scientific | 2026 |
| K&M Vehicles Ltd | Wholesale & retail | 2025 |
| K&V Transport Ltd | Transport & logistics | 2023 |
| K.E.M Beauty Ltd | Other services | 2020 |
| K.H.A.M Activewear and Fitness Ltd | Wholesale & retail | 2018 |