| Jomik Limited | Professional & scientific | 2011 |
| Jomosco Property Limited | Real estate | 2025 |
| Jona Solutions Limited | Information & communication | 2022 |
| Jonathan Leigh Limited | Professional & scientific | 2015 |
| Jonathan Newman LLP | | 2018 |
| Jonathan W. Carpenter Limited | Professional & scientific | 2010 |
| Jones & Wagener International Limited | Professional & scientific | 2019 |
| Jones & Wagener UK Limited | Professional & scientific | 2023 |
| Jonny Express Services Limited | Transport & logistics | 2020 |
| Jordan Albert Racing Ltd | Arts & recreation | 2020 |
| Jordan Bazzone Golf Ltd | Education | 2023 |
| Jordan Bidco Limited | Administrative & support | 2021 |
| Jordan Midco Limited | Administrative & support | 2021 |
| Jordan Newco Limited | Administrative & support | 2022 |
| Jordan Rose Consulting Ltd | Information & communication | 2025 |
| Jordan Topco Limited | Administrative & support | 2021 |
| Jorja Healthcare Holdings Ltd | Financial services | 2023 |
| Jose Logistics Ltd | Transport & logistics | 2026 |
| Joseph Furniture Ltd | Manufacturing | 2013 |
| Joseph James (LS) Limited | Professional & scientific | 2016 |
| Joseph Mcdonnell Ltd | Information & communication | 2025 |
| Josephine Bistro Limited | Hospitality | 2022 |
| Josephine Bouillon Parisian Limited | Hospitality | 2024 |
| Josephwunmi Limited | Health & social care | 2025 |
| Josetty Limited | Real estate | 2018 |
| Josh & Moyo Ltd | Information & communication | 2025 |
| Josh Home Properties Ltd | Real estate | 2023 |
| Josh Mccallum Consultancy Limited | Administrative & support | 2019 |
| Josh Rosales Photography Limited | Other services | 2021 |
| Joshel Ltd | Other services | 2021 |
| Joshi Industries Limited | Wholesale & retail | 2019 |
| Jotutorials Ltd | Education | 2022 |
| Joules Aviation Limited | Manufacturing | 2016 |
| Jourdan Housing Solutions Limited | Households | 2021 |
| Journey Projects Ltd | Professional & scientific | 2015 |
| Journey Protector (UK) Ltd | Professional & scientific | 2021 |
| Jovian Ventures Limited | Professional & scientific | 2024 |
| Jovic Plant Limited | Administrative & support | 1971 |
| Jowee Investments Limited | Real estate | 2017 |
| Jowee Solutions Limited | Professional & scientific | 2013 |
| Jowett Hotels Limited | Hospitality | 2001 |
| Joy Kaiser Limited | Manufacturing | 2023 |
| Joy Keepers Ltd | Health & social care | 2024 |
| Joy Sparkhome Limited | Wholesale & retail | 2024 |
| Joy Taxis Ltd | Transport & logistics | 2022 |
| Joyce Care Support Ltd | Health & social care | 2023 |
| Joycele Ltd | Administrative & support | 2018 |
| Joycometh Ltd | Health & social care | 2017 |
| Joyhome Builder Company Limited | Households | 2024 |
| Joyhome Property Management Limited | Real estate | 2021 |
| Joyhome Services Limited | Information & communication | 2017 |
| Joylands International Limited | Arts & recreation | 2020 |
| Joyous Enterprise Limited | Health & social care | 2013 |
| Joyresolve Limited | Professional & scientific | 2018 |
| Joyson Group Ltd | Financial services | 2026 |
| JP 426897 Limited | Information & communication | 2012 |
| JP Estates & Investments Limited | Real estate | 2025 |
| JP Fencing MK Ltd | Construction | 2023 |
| JP Financial Services Ltd | Financial services | 2024 |
| JP Global Holding Limited | Wholesale & retail | 2019 |
| JP Medical Holdings Limited | Real estate | 2019 |
| JP Nest EGG Collective Limited | Real estate | 2026 |
| JP Quality Electrics Limited | Manufacturing | 2016 |
| JP Ventures (UK) Limited | Information & communication | 2012 |
| JP Wills & Trusts Limited | Professional & scientific | 2025 |
| JPB Enterprises Ltd | Health & social care | 2017 |
| Jpcmdcproperties Ltd | Real estate | 2025 |
| JPK Talent Partners Ltd | Professional & scientific | 2025 |
| Jpkl Green FOX Limited | Administrative & support | 2022 |
| Jpma Properties Limited | Real estate | 2015 |
| Jpob Creative Services Ltd | Professional & scientific | 2018 |
| JPP Milton Keynes Limited | Professional & scientific | 2010 |
| Jpspencerholdings Ltd | Information & communication | 2023 |
| Jptuton Limited | Professional & scientific | 2013 |
| JR Ellis Limited | Real estate | 2025 |
| JR Film Services Limited | Information & communication | 2017 |
| JR Medicall Ltd | Wholesale & retail | 2019 |
| JR Work Support Ltd | Professional & scientific | 2023 |
| JR6 Properties Ltd | Real estate | 2017 |
| JRA Quality Testing Ltd | Information & communication | 2025 |
| Jra-Rmc Limited | Administrative & support | 2026 |
| JRB Portfolio Limited | Real estate | 2023 |
| JRC Milton Keynes Ltd | Hospitality | 2021 |
| Jrcc Holdings Ltd | Financial services | 2024 |
| Jrdn Services Ltd | Arts & recreation | 2026 |
| JRJ Consultancy Services Ltd | Administrative & support | 2023 |
| JRK PVT Limited | Wholesale & retail | 2017 |
| JRR Advice Ltd | Financial services | 2025 |
| Jrrd Aviation Limited | Manufacturing | 2022 |
| JRS Lettings Ltd | Real estate | 2019 |
| JRT Architectural Design Ltd | Professional & scientific | 2013 |
| JS Auto Sport Limited | Wholesale & retail | 2021 |
| JS Enterprise MK Limited | Wholesale & retail | 2023 |
| JS Global Solutions Ltd | Information & communication | 2026 |
| JS Investment Capital Ltd | Financial services | 2024 |
| JS Properties 1 Ltd | Real estate | 2017 |
| JS Properties 2 Ltd | Real estate | 2018 |
| JS Trading Stores Ltd | Wholesale & retail | 2024 |
| JS3 IT Solutions Limited | Professional & scientific | 2022 |
| Jsb-Networks Ltd | Information & communication | 2019 |