| JKS (2015) Ltd | Financial services | 2015 |
| Jksnp Communications Limited | Wholesale & retail | 2024 |
| JL Coastal Properties Ltd | Real estate | 2025 |
| JL Physiofit Ltd | Health & social care | 2019 |
| JL Property Consultants Ltd | Real estate | 2017 |
| JLAA1 Limited | Financial services | 2017 |
| Jlactivewear Ltd | Wholesale & retail | 2026 |
| JLD Energy Service Ltd | Other services | 2023 |
| JLD Stone Ltd | Construction | 2025 |
| JLF (NE) Limited | Professional & scientific | 2020 |
| JLH NE Property Limited | Real estate | 2024 |
| Jlhs Enterprises LLP | | 2011 |
| JLJ Community Inititaives C.I.C. | Health & social care | 2020 |
| Jlkj Properties Ltd | Real estate | 2013 |
| Jlrs Property Group Limited | Real estate | 2024 |
| JLT Peng Catering Ltd | Hospitality | 2026 |
| JM & AB Consultants Ltd | Professional & scientific | 2024 |
| JM BID Consultancy Ltd | Professional & scientific | 2025 |
| JM Blade Maintenance Ltd | Extraterritorial | 2024 |
| JM Building Maintenance (N.E.) Ltd | Construction | 2008 |
| JM Cabs Limited | Transport & logistics | 2009 |
| JM Homes Ltd | Real estate | 2018 |
| JM Houses NE Limited | Real estate | 2024 |
| JM Property and Management Group Ltd | Real estate | 2025 |
| JM Property NCL Limited | Real estate | 2024 |
| JM Trading North East Limited | Arts & recreation | 2023 |
| Jm-Imports Ltd | Wholesale & retail | 2006 |
| JMA Bathrooms Ltd | Construction | 2021 |
| JMA Interiors Ltd | Construction | 2020 |
| Jmaa Trading Ltd | Wholesale & retail | 2023 |
| JMB Family Protection Limited | Financial services | 2023 |
| JMC C & P Limited | Construction | 2026 |
| JMC Metal and Waste Recycling Limited | Water & waste | 2021 |
| JMC Systems Limited | | 1984 |
| Jmcg Construction Ltd | Construction | 2015 |
| JMCP10 Limited | Professional & scientific | 2021 |
| JMD Engineering Properties Limited | Real estate | 2012 |
| JMD Socials Ltd | Other services | 2023 |
| JMF Group Signage Ltd | Manufacturing | 2023 |
| JMF Print Limited | Manufacturing | 2002 |
| JMF Spray Ltd | Construction | 2026 |
| JMH Consulting Solutions Ltd | Information & communication | 2010 |
| JMH Partners Ltd | Financial services | 2024 |
| JMK Contractors Ltd | Construction | 2022 |
| JML Financial Consulting Limited | Professional & scientific | 2025 |
| JMS Completions Ltd | Professional & scientific | 2026 |
| JNA Architects Limited | Real estate | 2019 |
| JNB4TECH Ltd | Information & communication | 2023 |
| Jncg Limited | Professional & scientific | 2023 |
| JNE Building Services Limited | Construction | 2026 |
| Jnjc Property Ltd | Real estate | 2024 |
| JNP Electrical Services Ltd | Construction | 2022 |
| JO Bullerwell Hair Salon Limited | Other services | 2012 |
| JO Foods Limited | Hospitality | 2025 |
| Jo-Anne Garrick Limited | Professional & scientific | 2016 |
| JO11NLL Ltd | Real estate | 2025 |
| Joadesigns Limited | Professional & scientific | 2017 |
| Joan 120 Ltd | Real estate | 2021 |
| Joanie Consulting Ltd | Information & communication | 2024 |
| JOB4ME | Education | 2022 |
| Jobed Properties Ltd | Real estate | 2025 |
| Jobes Boxing & Fitness Gym CIC | Arts & recreation | 2016 |
| Jobes Sporting Promotions UK Ltd | Arts & recreation | 2026 |
| Jobling Automotive Engineering Ltd | Wholesale & retail | 2020 |
| Jobling Holdings Limited | Real estate | 2023 |
| Jobling Purser Limited | Manufacturing | 1992 |
| Jobling Purser R.S.V. LLP | | 2006 |
| Jobling Wealth Management Limited | Financial services | 2023 |
| Jodejay Ltd | Health & social care | 2016 |
| JOE Stewart Bespoke Ltd | Manufacturing | 2019 |
| Joeballantyne Limited | Professional & scientific | 2026 |
| Joestaverns Ltd | Hospitality | 2010 |
| Johann Host Productions Limited | Administrative & support | 2007 |
| Johe Property Ltd | Real estate | 2022 |
| John Arthur Drums Limited | Transport & logistics | 2017 |
| John Bradley Contracts Ltd | Professional & scientific | 2013 |
| John E Dunn Project Management Limited | Professional & scientific | 2010 |
| John F. Patrick Limited | Construction | 1993 |
| John Foley & SON (Tilers) Limited | Construction | 2004 |
| John Foley and SON Holdings Limited | Construction | 2019 |
| John Hopkinson Contracting Ltd | Transport & logistics | 2022 |
| John J. Alexander & Co. Limited | Real estate | 1943 |
| John Jackson Services Ltd | Mining & quarrying | 2019 |
| John Jobling Limited | Administrative & support | 2010 |
| John Lambert (Contractors) Ltd | Construction | 2016 |
| John Mcleod Robertson Limited | Administrative & support | 2024 |
| John Morley (Coachworks) Limited | Extraterritorial | 1947 |
| John Naylor (Bakers) Limited | | 1975 |
| John Nixon Limited | Administrative & support | 1967 |
| John Palmer (Builders) Limited | | 1984 |
| John Reed Associates Limited | Information & communication | 2009 |
| John Spencer Wellsite Geological Consultancy Limited | Mining & quarrying | 2008 |
| John T Bell & Sons (1976) Limited | Professional & scientific | 1973 |
| John Thompson (Pressure Vessel Division) Limited | | 1936 |
| John Turner Roofing & Building Services Limited | Construction | 2019 |
| John William Thompson Ltd | Extraterritorial | 2024 |
| John Williams (Liverpool) Limited | | 1922 |
| John Wilson Laybourn Limited | Real estate | 2024 |
| John Wilson Limited | Wholesale & retail | 2014 |
| Johnjasper Associates Ltd | Administrative & support | 2017 |