| Jackson's Plastering & DRY Lining Limited | Construction | 2000 |
| Jackson's Plastering & DRY Lining Partnership LLP | | 2012 |
| Jackson's Plastering and DRY Lining Partners LLP | | 2012 |
| Jade Construction Limited | Construction | 2023 |
| Jade Entertainment Limited | Other services | 2024 |
| Jade Insulation Limited | Construction | 2010 |
| Jade's Logistics Limited | Transport & logistics | 2024 |
| Jaded Heart Ltd | Wholesale & retail | 2016 |
| Jadeella Designs Ltd | Professional & scientific | 2026 |
| Jadeella Ltd | Wholesale & retail | 2023 |
| Jagga Spice Limited | Hospitality | 2022 |
| Jaguar Property Management Limited | Real estate | 2016 |
| Jaguar Signs Limited | Manufacturing | 1989 |
| Jake Cook Limited | Wholesale & retail | 2011 |
| Jake Duggan Ltd | Administrative & support | 2021 |
| Jakedesigns Graphics Limited | Other services | 2016 |
| Jameel Developments Ltd | Administrative & support | 2026 |
| Jameel Investments Ltd | Administrative & support | 2026 |
| James Bromley Transport Limited | Transport & logistics | 2019 |
| James FOX & Sons Limited | Real estate | 1974 |
| James Lake Hospitality Limited | Administrative & support | 2018 |
| James Pink Advisory Services Limited | Professional & scientific | 2021 |
| James Sidney Ltd | Extraterritorial | 2017 |
| James Todd Forensic Consulting Limited | Health & social care | 2020 |
| Jamie Heyes Transport Limited | Transport & logistics | 2013 |
| Jamirigs Ltd | Wholesale & retail | 2025 |
| Jamjamz Limited | Health & social care | 2024 |
| Jandl Worldwide Global Solutions Ltd | Professional & scientific | 2026 |
| Jandrew Logistics Limited | Transport & logistics | 2019 |
| Jane Phillips Consulting Ltd | Professional & scientific | 2019 |
| Janet Cuckson Medical Limited | Health & social care | 2016 |
| Jani Ltd | Information & communication | 2026 |
| Janice Johnson Limited | Health & social care | 2018 |
| Janiki Apparel Limited | Wholesale & retail | 2025 |
| Janus Education Limited | Professional & scientific | 2019 |
| Janus Motors Limited | Wholesale & retail | 2013 |
| Janus Property Investments Ltd | Real estate | 2026 |
| Jared Rose Properties Ltd | Real estate | 2020 |
| Jarly Limited | Other services | 2016 |
| Jars Cleaning Services Ltd | Administrative & support | 2025 |
| Jarvis & Co Accounting Limited | Professional & scientific | 2021 |
| Jarvis & Womack Limited | Construction | 1926 |
| Jarvis and Womack Holdings Limited | Financial services | 2023 |
| Jarvis Electrical Services Ltd | Manufacturing | 2019 |
| Jason Shutter Specialist Ltd | Wholesale & retail | 2025 |
| Jatt 121 Ltd | Real estate | 2022 |
| JAW (Properties) Limited | Real estate | 2015 |
| Jaxx Irish Bar Ltd | Hospitality | 2026 |
| Jaxx Rotherham Ltd | Hospitality | 2025 |
| JAY MD Business Support Ltd | Administrative & support | 2026 |
| JAY Travel Ltd | Transport & logistics | 2026 |
| Jayamk Ltd | Health & social care | 2021 |
| Jaycliffe Hydrotherapy Ltd | Professional & scientific | 2025 |
| Jayfj Ltd | Wholesale & retail | 2022 |
| Jaylo Property Services Ltd | Real estate | 2023 |
| Jays Mart Express Ltd | Wholesale & retail | 2025 |
| Jayz Cardz Ltd | Wholesale & retail | 2023 |
| JB & S Transport Limited | Transport & logistics | 2025 |
| JB Auto Electrics Limited | Wholesale & retail | 2011 |
| JB Development Yorkshire Ltd | Construction | 2022 |
| JB Engineering Services Ltd | Manufacturing | 2012 |
| JB Learning Ltd | Education | 2022 |
| JB Partitions & Ceilings Ltd | Construction | 2022 |
| JB Rigging Limited | Information & communication | 2021 |
| JB Transformations Ltd | Education | 2025 |
| JBA Electrical Services Ltd | Construction | 2024 |
| JBC Electrical Ltd | Manufacturing | 2023 |
| Jbfc Property Limited | Administrative & support | 2025 |
| Jbfloors Ltd | Extraterritorial | 2022 |
| JBI Business Ltd | Hospitality | 2023 |
| JBM Plant and Recycling Ltd | Financial services | 2022 |
| JBM Plastering Ltd | Construction | 2017 |
| JBP Construction Consultants Ltd | Construction | 2022 |
| Jbwill Properties Ltd | Real estate | 2019 |
| JC Construction and Civils Limited | Construction | 2019 |
| JC Construction Yorkshire Ltd | Real estate | 2022 |
| JC Delivery & Supply Chain Solutions Ltd | Transport & logistics | 2025 |
| JC International Investments Ltd | Real estate | 2022 |
| JC Mortgage Services Ltd | Financial services | 2020 |
| JC Property Repairs Ltd | Construction | 2019 |
| JC Property Services & Maintenance Limited | Construction | 2025 |
| JC Property Solutions 1989 Ltd | Real estate | 2021 |
| JC Rail Training Ltd | Education | 2023 |
| JC Residential Investments Ltd | Real estate | 2020 |
| JCC Limited | Construction | 2022 |
| Jcct Ltd | Professional & scientific | 2014 |
| Jcec Electrical Solutions Ltd | Construction | 2023 |
| JCH Consultancy Limited | Other services | 2021 |
| JCH Decorators Limited | Construction | 2022 |
| JD Dental Limited | Health & social care | 2021 |
| JD Engineers Ltd | Professional & scientific | 2026 |
| JD Hall Engineering Ltd | Professional & scientific | 2026 |
| JD Management Consultants Ltd | Professional & scientific | 2007 |
| JD Rigging Solutions Limited | Information & communication | 2022 |
| JD Sanders Limited | Construction | 2018 |
| JD Tools Limited | Wholesale & retail | 2016 |
| JDA Customs Limited | Other services | 2019 |
| JDB Glazing Ltd | Construction | 2024 |
| JDD Fitness Limited | Arts & recreation | 2025 |
| JDD Strength & Recovery Hub Limited | Other services | 2026 |