| Ionotec Ltd | Manufacturing | 1995 |
| Ipmc Properties Ltd | Real estate | 2021 |
| Iridium Education Ltd | Education | 2016 |
| Iron Tread Tyres Ltd | Wholesale & retail | 2025 |
| Isol (Intelligent Solutions) Limited | Professional & scientific | 2020 |
| Isomi Ltd | Manufacturing | 2006 |
| Isomi Projects Ltd | Manufacturing | 2015 |
| Isomi USA Ltd | Manufacturing | 2016 |
| Isys International Limited | Professional & scientific | 2001 |
| Itsamannsworld Ltd | Information & communication | 2010 |
| J & K Catering Limited | Hospitality | 2024 |
| J & S Pearce Logistics Ltd | Transport & logistics | 2021 |
| J Bearock TM Ltd | Construction | 2024 |
| J C Automation Limited | Manufacturing | 2013 |
| J C Peacock & Company (Astmoor) Limited | Manufacturing | 2014 |
| J Cheung EVO Ltd | Professional & scientific | 2020 |
| J F Kennedy Haulage Limited | Transport & logistics | 2018 |
| J J Lifetime Solutions Limited | Professional & scientific | 2016 |
| J K Tool Hire Limited | Real estate | 2007 |
| J P R Commercials Limited | Wholesale & retail | 2014 |
| J R Holt Engineering Limited | Professional & scientific | 2016 |
| J Wilkins Nutrition Ltd | Hospitality | 2025 |
| J.B. Pearson Property Ltd | Real estate | 2017 |
| J.F.B. Cores Limited | Manufacturing | 1987 |
| J2 Systems Technology Limited | Financial services | 2003 |
| Jack N’ Harry’S Ltd | Wholesale & retail | 2026 |
| Jack Power Boxing Ltd | Arts & recreation | 2025 |
| Jack Rimmer Contracting Ltd | Construction | 2024 |
| Jackson's Boat (Gastro) Limited | Hospitality | 2025 |
| Jaguar Chemical Distribution Ltd | Wholesale & retail | 2024 |
| Jaii Habite Ltd | Real estate | 2022 |
| Jake Alexander Ltd | Other services | 2018 |
| Jake Newall Decorators Ltd | Construction | 2024 |
| JAM Marketing and Social Media Ltd | Administrative & support | 2018 |
| James Cross Ltd | Administrative & support | 2011 |
| James Ferguson Communications Ltd | Information & communication | 2023 |
| James Grace Estates Ltd | Real estate | 2020 |
| James O'Rourke Ltd | Construction | 2023 |
| James Troop & Company Limited | Manufacturing | 1918 |
| Janka Transport Ltd | Transport & logistics | 2022 |
| JB Creative Agency Ltd | Professional & scientific | 2020 |
| JBM Hire Limited | Transport & logistics | 2013 |
| JC Project Management Solutions Ltd | Professional & scientific | 2011 |
| JDS Property Management Ltd | Households | 2018 |
| Jeanie Ellen Ltd | Wholesale & retail | 2022 |
| JEC Business Finance Limited | Financial services | 2022 |
| JEC Logistics Ltd | Transport & logistics | 2021 |
| JEC Management Co Limited | Administrative & support | 2022 |
| JEM Properties (Liverpool) Ltd | Real estate | 2022 |
| JEM Recycling and Waste Management Ltd | Water & waste | 2013 |
| Jenny Beauty Ltd | Other services | 2024 |
| Jetting Services (North West) Limited | Manufacturing | 2011 |
| JG Trinity Ec&I Design Services Ltd | Professional & scientific | 2025 |
| Jgmsports Limited | Administrative & support | 2017 |
| JH Building Contractors Ltd | Construction | 2015 |
| JH2 Properties Ltd | Real estate | 2018 |
| Jj's Cafe and Desserts Ltd | Hospitality | 2025 |
| Jj's Early Explorers Ltd | Education | 2019 |
| JJK Enterprises Limited | Wholesale & retail | 2023 |
| Jjpp Holdings Limited | Hospitality | 2020 |
| JKA Electronics Limited | Manufacturing | 2013 |
| JLD Automove Ltd | Transport & logistics | 2025 |
| JLI Project Solutions Ltd | Professional & scientific | 2013 |
| Jmbm Solutions Ltd | Construction | 2026 |
| JMC Test Services Limited | Information & communication | 2014 |
| Jmsretailers Ltd | Wholesale & retail | 2026 |
| JNT Holdings Ltd | Wholesale & retail | 2022 |
| Joda Heating & Building Services Limited | Administrative & support | 2016 |
| Joel Jordan Properties Ltd | Households | 2025 |
| John Deering Limited | Wholesale & retail | 2024 |
| Johnny's Cleaning Services Ltd | Administrative & support | 2025 |
| Johnson Group Cleaners Trustee Company (NO.1) Limited | Professional & scientific | 1937 |
| Johnson Group Cleaners Trustee Company (NO.2) Limited | Professional & scientific | 1906 |
| Johnson Group Inc (UK) Limited | Professional & scientific | 1990 |
| Johnson Group Management Services Limited | Administrative & support | 1884 |
| Johnson Group Pension Nominees Limited | Administrative & support | 1943 |
| Johnson Group Properties PLC | Construction | 1953 |
| Johnson Hospitality Services Limited | Administrative & support | 1999 |
| Johnson Investment Limited | Professional & scientific | 1999 |
| Johnson's for Jobs Limited | Administrative & support | 2016 |
| JON Yarker Freelance Ltd | Information & communication | 2024 |
| Jonesee Rail Ltd | Construction | 2015 |
| Jonnic Properties Limited | Real estate | 2020 |
| Jordan's Rentals Ltd | Households | 2025 |
| Jozger Ltd | Manufacturing | 2023 |
| Jozger Properties Ltd | Real estate | 2025 |
| JP IVD Consulting Ltd | Professional & scientific | 2025 |
| JSG PLC | Professional & scientific | 1967 |
| JSL Engineering Services (UK) Limited | Professional & scientific | 2012 |
| Jssp Property Management Ltd | Real estate | 2021 |
| JT Instore Solutions Ltd | Construction | 2023 |
| Jtee Consultancy Limited | Education | 2022 |
| JTW Creative Limited | Administrative & support | 2011 |
| Juame Rich Limited | Health & social care | 2017 |
| Juniper Clinic Ltd | Health & social care | 2021 |
| Just Commercial Property Limited | Real estate | 2019 |
| Just Residential Limited | Real estate | 2019 |
| JW Consultation Ltd | Professional & scientific | 2025 |
| JW Hampton & Co Ltd | Administrative & support | 2025 |
| JW Taxi Services Ltd | Transport & logistics | 2022 |