| JIM Boys Ice Cream Limited | Administrative & support | 2020 |
| JIM Cooling Automation Ltd | Information & communication | 2025 |
| Jimal Group Ltd | Information & communication | 2025 |
| Jimsco Developments Limited | Construction | 2025 |
| Jinkko Ltd | Wholesale & retail | 2018 |
| Jisac AGE Ltd | Wholesale & retail | 2022 |
| Jishu Ltd | Wholesale & retail | 2026 |
| Jitte Group Limited | Professional & scientific | 2019 |
| JIZ Omeire Limited | Health & social care | 2024 |
| JJ Agri Wholesale Ltd | Agriculture & fishing | 2025 |
| JJ Amari Investments Limited | Real estate | 2025 |
| JJ Trans Ltd | Transport & logistics | 2016 |
| JJ Tree & Landscape Services Ltd | Administrative & support | 2012 |
| Jjab Construction Ltd | Construction | 2022 |
| Jjai Ltd | Professional & scientific | 2023 |
| JJD Angelos Ltd | Professional & scientific | 2024 |
| Jjdv Limited | Manufacturing | 2026 |
| Jjlg Investments Property Limited | Hospitality | 2022 |
| JJM Facilities Services Group Limited | Administrative & support | 2025 |
| JJM Services Group Limited | Administrative & support | 2018 |
| JJP Enterprises (Cambs) Ltd | Hospitality | 2016 |
| JJP Joinery Ltd | Construction | 2024 |
| JJT Interiors Ltd | Construction | 2025 |
| JJT Property (London) Services Ltd | Construction | 2025 |
| JK Mortgages Limited | Financial services | 2017 |
| Jkaoycapital Ltd | Financial services | 2023 |
| JKC Trading Limited | Extraterritorial | 2020 |
| JKC Ventures Ltd | Wholesale & retail | 2026 |
| JKK Music Limited | Information & communication | 2020 |
| JKP Consulting Limited | Wholesale & retail | 2025 |
| JKS Coaching LLP | | 2014 |
| JL Asset Management Limited | Administrative & support | 2025 |
| JL Care Homes Limited | Real estate | 2024 |
| JL Hmos Limited | Real estate | 2025 |
| JL Interior Contractors Ltd | Construction | 2025 |
| JL Property Holdings Limited | Financial services | 2024 |
| JL Resell Ltd | Other services | 2026 |
| JL Will Writer Ltd | Professional & scientific | 2024 |
| JLF Executive Search Ltd | Administrative & support | 2011 |
| Jliral Retail Ltd | Wholesale & retail | 2021 |
| JLT Mechanical Design Limited | Professional & scientific | 2011 |
| Jlts Construction Ltd | Construction | 2025 |
| JM Automotive Services Ltd | Wholesale & retail | 2018 |
| JM Building Developments LLP | | 2015 |
| JM Carpentry + Joinery Developments LLP | | 2015 |
| JM Facilities Solutions Ltd | Professional & scientific | 2025 |
| JM Goncalves Ltd | Construction | 2023 |
| JM Properties (Peterborough) Limited | Real estate | 2011 |
| JM Wilkinson Property Ltd | Real estate | 2022 |
| JM75 Team Limited | Administrative & support | 2017 |
| JMA Design & Developments Limited | Construction | 2022 |
| JMC Electrical(Uk) Ltd | Construction | 2024 |
| Jmeg Property Ltd | Real estate | 2024 |
| Jmej Limited | Health & social care | 2015 |
| JMG Accounting & Consulting Limited | Professional & scientific | 2024 |
| JMK Contracts Ltd | Water & waste | 2020 |
| JML People Solutions Ltd | Professional & scientific | 2026 |
| JMR Installations Ltd | Construction | 2022 |
| JMS Infotec Limited | Wholesale & retail | 2005 |
| JMS Sales Consultant Ltd | Manufacturing | 2025 |
| JMS Transformers Limited | Manufacturing | 2002 |
| JMS Transport Ltd | Transport & logistics | 2018 |
| Jmti Ltd | Wholesale & retail | 2016 |
| JMV Property Management Ltd | Real estate | 2018 |
| JN Lawlings Limited | Professional & scientific | 2025 |
| JN Training Limited | Education | 2024 |
| Jnas Safety Solutions Ltd | Professional & scientific | 2025 |
| JNB IT Ltd | Information & communication | 2025 |
| Jncare Ltd | Health & social care | 2018 |
| Jncc Support Co | Professional & scientific | 2005 |
| JNP Developments Limited | Administrative & support | 2005 |
| Jnrsg Properties Ltd | Real estate | 2026 |
| JNS Investments Limited | Real estate | 2004 |
| Jo-Company Accountants for YOU Limited | Professional & scientific | 2026 |
| JOA Investment Limited | Health & social care | 2020 |
| Joanna David Ltd | Health & social care | 2019 |
| Joanna Miguel Ltd | Wholesale & retail | 2021 |
| Joaquim Aggregates Limited | Construction | 2024 |
| Joba Projects Ltd | Administrative & support | 2017 |
| Jobs and Visits Planner Ltd | Information & communication | 2026 |
| Jobs at Heart Limited | Wholesale & retail | 2019 |
| Jody Carter Ltd. | Professional & scientific | 2014 |
| JOE Mortar Limited | Real estate | 2017 |
| JOE Vine Limited | Hospitality | 2019 |
| Johamish Services Ltd | Administrative & support | 2023 |
| Johanna's Sandwich Bar Limited | Hospitality | 2002 |
| John Amps Properties Limited | Real estate | 2004 |
| John Bradshaw Limited | Manufacturing | 1976 |
| John Building Service 1980 Ltd | Construction | 2019 |
| John Clare (Helpston) Limited | Other services | 2007 |
| John Clow HTC Ltd | Wholesale & retail | 2026 |
| John Dickie Associates Limited | Professional & scientific | 2010 |
| John Eley Signs Limited | Manufacturing | 2010 |
| John F. Dunkling Limited | Construction | 2004 |
| John Forest Contracts Ltd | Construction | 2023 |
| John Griffiths Cars Limited | Wholesale & retail | 2015 |
| John Lucas Funeral Directors Limited | Extraterritorial | 2025 |
| John Lucas(Peterborough),Limited | Construction | 1935 |
| John Mary Investments Limited | Financial services | 2018 |
| John Walker Gibbon Limited | Financial services | 2005 |