| Japan World Ltd | Wholesale & retail | 2023 |
| Jarda Medical Services Ltd | Health & social care | 2021 |
| Jarda Properties Ltd | Real estate | 2021 |
| Jardine Project Services Limited | Administrative & support | 2016 |
| JAS Electrical Contracting Ltd | Construction | 2013 |
| JAS Electrical Maintenance Limited | Construction | 2009 |
| JAS Oakes Management Services Ltd | Construction | 2021 |
| JAS Reporting Limited | Information & communication | 2024 |
| Jasim's Organization Ltd | Transport & logistics | 2025 |
| JAT Cars Limited | Wholesale & retail | 2013 |
| Jatt Holdings Ltd | Real estate | 2026 |
| Javid Consultancy Ltd | Professional & scientific | 2025 |
| Javu Solution Ltd | Wholesale & retail | 2025 |
| JAY Motors Limited | Wholesale & retail | 2024 |
| JAY Professional Painting and Decorating Company Ltd | Construction | 2021 |
| Jaydec Ltd | Construction | 2016 |
| Jaydee Aesthetics Ltd | Health & social care | 2019 |
| Jayfort Security Services Limited | Administrative & support | 2001 |
| Jayray Vehicle Solutions Limited | Wholesale & retail | 2002 |
| Jayy CEE Consultancy Ltd | Professional & scientific | 2026 |
| Jazcoo Limited | Wholesale & retail | 2026 |
| JB Accountancy Limited | Professional & scientific | 2018 |
| JB and DB Property Limited | Real estate | 2023 |
| JB Asset Management Ltd | Real estate | 2024 |
| JB Himalayan Salt Ltd | Wholesale & retail | 2019 |
| JB Investment Holdings Ltd | Financial services | 2026 |
| JB Lifestyle Ltd | Health & social care | 2024 |
| JB Profound Construction Ltd | Construction | 2020 |
| JB Scenic Art Ltd | Arts & recreation | 2019 |
| JB Valves Limited | Manufacturing | 2014 |
| JBF Developments Limited | Real estate | 2021 |
| JBM Yorkshire Limited | Manufacturing | 2023 |
| Jbras (Consultants) Ltd | Professional & scientific | 2023 |
| Jbre Ltd | Real estate | 2013 |
| Jbridge CIC | Real estate | 2020 |
| JC Access Ltd | Construction | 2026 |
| JC Creative Consultancy Ltd | Professional & scientific | 2022 |
| JC Forestry Limited | Agriculture & fishing | 2011 |
| Jc's Fresh Preps Limited | Hospitality | 2019 |
| Jcms Services Limited | Manufacturing | 2026 |
| JCR Builders Construction & Development Ltd | Construction | 2018 |
| JCR Data Solutions Ltd | Information & communication | 2023 |
| JCS Daily Mart Ltd | Wholesale & retail | 2025 |
| JCS Mini Market Ltd | Wholesale & retail | 2025 |
| JCS-2E Care Services Limited | Health & social care | 2015 |
| JCU Services Ltd | Administrative & support | 2020 |
| JD Coaching and Training Ltd | Health & social care | 2025 |
| JD Construction North East Limited | Construction | 2016 |
| JD Partsalvagers Ltd | Wholesale & retail | 2013 |
| JD Robinson's Ltd | Construction | 2023 |
| JDF Maintenance (Huddersfield) Limited | Construction | 2017 |
| JDL Asbestos Consultants Ltd | Administrative & support | 2025 |
| JDL Plumbing & Heating Ltd | Construction | 2014 |
| JDR Computing Ltd | Information & communication | 2015 |
| JDS Roofing Limited | Construction | 2023 |
| JDS63 Ltd | Hospitality | 2023 |
| JDY Timber Ltd | Wholesale & retail | 2021 |
| JE Koyo Ltd | Hospitality | 2026 |
| JEB Joinery and Construction Ltd | Construction | 2010 |
| Jebson Developments Limited | Construction | 2006 |
| Jecha Ltd | Construction | 2017 |
| Jedok Services Ltd | Hospitality | 2025 |
| Jeewan Organic World Ltd | Wholesale & retail | 2023 |
| Jehanshah Ltd | Wholesale & retail | 2025 |
| JEL Project Management Ltd | Professional & scientific | 2021 |
| Jelly Tots Nursery (Goole) Ltd | Education | 2018 |
| Jemi 21 Limited | Real estate | 2019 |
| Jemstrat Limited | Information & communication | 2022 |
| Jenbot Sportswear Limited | Wholesale & retail | 2023 |
| Jenks & Cattell Limited | Professional & scientific | 1964 |
| Jenndya Ltd | Hospitality | 2022 |
| Jentin &Biby Company Ltd | Real estate | 2021 |
| Jeremy Hodge Ltd | Real estate | 2016 |
| Jerk House Limited | Hospitality | 2023 |
| Jerk Junction Limited | Hospitality | 2018 |
| Jessop Brickwork Ltd | Construction | 2020 |
| Jest Services Limited | Real estate | 2025 |
| Jeta Property Developments Ltd | Real estate | 2003 |
| Jetium Limited | Transport & logistics | 2015 |
| JEWELS4YOU Ltd | Wholesale & retail | 2024 |
| JF Music Ltd | Information & communication | 2018 |
| JFB Sales and Services Ltd | Wholesale & retail | 2025 |
| JFO Care Group Ltd | Health & social care | 2026 |
| JGL Industrial Ltd | Professional & scientific | 2025 |
| JGV Chauffeur Ltd | Transport & logistics | 2026 |
| Jh&L Enterprises Ltd | Hospitality | 2023 |
| Jhoom Events Ltd | Hospitality | 2024 |
| Jhrms Limited | Financial services | 2022 |
| JHW Properties (Yorkshire) Ltd | Financial services | 2024 |
| JI Driveways Ltd | Construction | 2024 |
| JI Electronics Limited | Wholesale & retail | 2009 |
| JI Express Ltd | Health & social care | 2014 |
| Jibstick Ltd. | Information & communication | 2015 |
| Jidenna Limited | Real estate | 2025 |
| Jigby Training Solutions Limited | Education | 2015 |
| Jigsaw Commercial Finance Limited | Financial services | 2017 |
| Jill Yvette's Holistic Beauty Limited | Other services | 2002 |
| Jitterbugs Nurseries Limited | Other services | 2003 |
| JJ Groundwork&Jetting Ltd | Construction | 2025 |
| Jj's Recruitment Ltd | Administrative & support | 2023 |