| JR Install Ltd | Construction | 2024 |
| JR Sales Limited | Wholesale & retail | 2015 |
| JR Stedman Carpentry Services Ltd | Construction | 2023 |
| JR Walden Limited | Real estate | 2013 |
| Jrbitconsultancy Limited | Information & communication | 2025 |
| JRE3 Limited | Professional & scientific | 2023 |
| Jrisk RM Ltd | Other services | 2018 |
| JRT Scaffolding Services Ltd | Construction | 2024 |
| Jrtm Solutions Ltd | Transport & logistics | 2016 |
| Jruks Ltd | Hospitality | 2017 |
| JRW Law Limited | Professional & scientific | 2016 |
| JS (Colchester) Ltd | Real estate | 2023 |
| JS Flat Roofing Specialists Ltd | Construction | 2024 |
| JS Green Property Ltd | Real estate | 2024 |
| JS Lounge (UK) Ltd | Hospitality | 2018 |
| JSB Electrical Services Ltd | Construction | 2021 |
| Jsbs-Gadget Ltd | Wholesale & retail | 2017 |
| JSC Group Holdings Ltd | Financial services | 2021 |
| JSC Group Interiors Ltd | Manufacturing | 2021 |
| Jsfinvestmentsourcing Ltd | Real estate | 2025 |
| JSH Property Solutions Ltd | Construction | 2015 |
| JSJ Medicals Limited | Health & social care | 2024 |
| JSK Tech Limited | Information & communication | 2022 |
| JSP Plumbing & Heating Ltd | Construction | 2023 |
| JST Web Development Limited | Information & communication | 2019 |
| JSZ Transport Ltd | Transport & logistics | 2019 |
| JT Solutions Limited | Information & communication | 2025 |
| JTA Safety Limited | Professional & scientific | 2020 |
| JTB Commercial Ltd | Construction | 2017 |
| JTB Property Ventures Ltd | Real estate | 2020 |
| Jthn Limited | Professional & scientific | 2012 |
| JTL Events Management Ltd | Professional & scientific | 2025 |
| Jtliftservices Limited | Construction | 2024 |
| Jtrhomes Ltd | Real estate | 2023 |
| JTS Plumbing & Maintenance Ltd | Administrative & support | 2017 |
| Jttp Ltd | Health & social care | 2020 |
| JTW Housing Ltd | Real estate | 2026 |
| Jubilee Close (Stanway) Management Company Limited | Households | 2019 |
| Jubilee Friends Limited | Education | 2009 |
| Jubilee Home (Sunderland) Limited | Health & social care | 2000 |
| Judge Finance Limited | Professional & scientific | 2025 |
| Judith Davis Limited | Professional & scientific | 2004 |
| Judith Winward Notary Public Ltd | Professional & scientific | 2026 |
| Juggle Distribution Limited | Wholesale & retail | 2023 |
| Jugnow Limited | Extraterritorial | 2017 |
| Julian Orman Ltd | Construction | 2013 |
| Julian Wilkins Ltd | Arts & recreation | 2011 |
| Julien Lawrence Surveying Ltd | Professional & scientific | 2023 |
| Julisa Group Ltd | Wholesale & retail | 2016 |
| Jumanda Ltd | Health & social care | 2019 |
| Jumeg Limited | Real estate | 2020 |
| Junejo Consulting Limited | Health & social care | 2024 |
| Juno Resources Limited | Professional & scientific | 2013 |
| Jupes Hill Capital Ltd | Professional & scientific | 2019 |
| Just BE Steez Ltd | Manufacturing | 2014 |
| Just Beachy Ltd | Wholesale & retail | 2022 |
| Just Better Marketing Ltd. | Information & communication | 2023 |
| Just Gorgeous Limited | Professional & scientific | 2002 |
| Just in Time Physiotherapy Ltd | Other services | 2020 |
| Just Leadership Ltd | Professional & scientific | 2024 |
| Just Mortgages Direct Limited | Financial services | 1989 |
| Just One More Development Ltd | Real estate | 2021 |
| Just Practising Limited | Information & communication | 2015 |
| Just SO Ideas Limited | Manufacturing | 2017 |
| Just Social Marketing Ltd | Professional & scientific | 2021 |
| Just Tasty Ltd | Hospitality | 2024 |
| Just Train CIC | Education | 2025 |
| Justbeef Limited | Wholesale & retail | 2024 |
| Justice Mate Legal Services Ltd | Professional & scientific | 2024 |
| Justin Scott Clark Limited | Information & communication | 2024 |
| Justin Utilities Ltd | Construction | 2017 |
| Justnamed Ltd | Information & communication | 2014 |
| JV Print Limited | Manufacturing | 2022 |
| JVE Properties Ltd | Real estate | 2025 |
| JVH Newco Limited | Professional & scientific | 2024 |
| JW (Wickham) Ltd | Administrative & support | 2014 |
| JW Build Limited | Professional & scientific | 2016 |
| JW MMA Limited | Education | 2025 |
| JW Smart Company Ltd | Construction | 2021 |
| JW Total Services Ltd | Construction | 2024 |
| JWB Automotive Group Limited | Financial services | 2024 |
| JWB Car Detailing Limited | Wholesale & retail | 2020 |
| JWB Web Enterprises Ltd | Information & communication | 2022 |
| JWD Global Ltd | Real estate | 2022 |
| JWE Ward Limited | Information & communication | 2008 |
| JWL Artists Ltd | Administrative & support | 2005 |
| JWP RAW Materials Ltd | Wholesale & retail | 2024 |
| Jyllp Limited | Financial services | 2026 |
| Jyochan Limited | Information & communication | 2018 |
| Jystock Limited | Wholesale & retail | 2017 |
| K & D Capital Partners L.P. | | 2012 |
| K & E Woodburners Ltd | Construction | 2019 |
| K & G Afro-Caribbean Groceries Ltd | Wholesale & retail | 2022 |
| K & M Roast Installations Ltd | Construction | 2003 |
| K a Cleaning Limited | Administrative & support | 2014 |
| K and J Construction Ltd | Construction | 2019 |
| K and J Fabrication Limited | Construction | 2022 |
| K Arday Consulting Ltd | Professional & scientific | 2024 |
| K B C Installations Limited | Construction | 2004 |
| K Bull Electrical Ltd | Construction | 2026 |