| Indeeko Ltd | Wholesale & retail | 2024 |
| Indeffe Ltd | Professional & scientific | 2019 |
| Indigo Night Light Limited | Extraterritorial | 2008 |
| Indomitus Solutions Ltd | Arts & recreation | 2024 |
| Industracare Limited | Wholesale & retail | 2014 |
| Innopath Ltd | Professional & scientific | 2025 |
| Innovate Coaching Ltd | Education | 2025 |
| Innovate Vision LAB Ltd | Information & communication | 2025 |
| Innovate Web Solutions Limited | Information & communication | 2017 |
| Innovative Installations Ltd | Construction | 2025 |
| Inotec Solutions Ltd | Information & communication | 2023 |
| Inspection Services NDT Ltd | Professional & scientific | 2008 |
| Inspiral Cycles Ltd | Manufacturing | 2014 |
| Inspired NLP Ltd | Health & social care | 2024 |
| Integrated Technical Solutions Limited | Construction | 2003 |
| Intelligent Sport Technologies Ltd | Information & communication | 2019 |
| Intentional Group Ltd | Information & communication | 2026 |
| Inter-Face Training and Consultancy Limited | Education | 2012 |
| Interior DNA Limited | Professional & scientific | 2013 |
| Interition Digital Transformation Limited | Information & communication | 2020 |
| Interscreens Ltd | Wholesale & retail | 2016 |
| Inventory Outsourcing Limited | Administrative & support | 2005 |
| Inventurist Limited | Financial services | 2019 |
| Invest in Nature C.I.C. | Education | 2024 |
| ISOL8 Properties Investment Ltd | Hospitality | 2025 |
| Its-A-Breeze Ltd | Information & communication | 2000 |
| Iulmar Trans Logistics Ltd | Transport & logistics | 2022 |
| Izumi Products UK Limited | Manufacturing | 1995 |
| J & a Roofing Limited | Construction | 2005 |
| J & MR Investments Ltd | Real estate | 2014 |
| J Brown Consultants Limited | Professional & scientific | 2021 |
| J Carrigan Roofing & Cladding Limited | Construction | 2018 |
| J Corless Limited | Health & social care | 2010 |
| J Elliott Properties Ltd | Real estate | 2023 |
| J I W Heating Services Limited | Construction | 2006 |
| J J S Road Maintenance Limited | Wholesale & retail | 2009 |
| J Jimminson Roofing & Cladding Limited | Construction | 2020 |
| J Kelsey Joinery Ltd | Construction | 2026 |
| J Kempsey Ltd | Wholesale & retail | 2025 |
| J M W Plant Engineering Ltd | Professional & scientific | 2024 |
| J Maddison Holdings Limited | Financial services | 2022 |
| J Mitchinson Limited | Manufacturing | 2011 |
| J R & S Commercial Properties Ltd | Real estate | 2023 |
| J R & S Properties Ltd | Real estate | 2020 |
| J Reed Investments Ltd | Real estate | 2017 |
| J Terry Electrical Limited | Administrative & support | 2003 |
| J Thirlaway Limited | Administrative & support | 2020 |
| J&A Power Washing & Gardening Services Ltd | Administrative & support | 2025 |
| J&I Roofing Ltd | Construction | 2025 |
| J&M Floor Screeds Ltd | Construction | 2013 |
| J.D. Crosby & Co Limited | Construction | 2000 |
| J.G. Tyre Services Limited | Wholesale & retail | 2002 |
| J.W. Crosby & Company Limited | Construction | 2000 |
| Jagdesign (4M) Ltd | Manufacturing | 2017 |
| JAI Services Ltd | Transport & logistics | 2025 |
| JAL Property Limited | Real estate | 2015 |
| Jalilo Limited | Real estate | 2015 |
| Jallan Properties Limited | Real estate | 2023 |
| JAM Property Management Limited | Households | 2019 |
| Jambay Ltd | Real estate | 2018 |
| James Kirwin P&H Ltd | Construction | 2022 |
| James Murray Consultants Limited | Professional & scientific | 2008 |
| Jana Property Ltd | Real estate | 2021 |
| Jane Seagrave Properties Ltd | Real estate | 2025 |
| Janet and John Kiddies Rides Ltd | Arts & recreation | 2013 |
| Jarmacoe Solutions Limited | Agriculture & fishing | 2008 |
| JAS Designing Ltd | Professional & scientific | 2021 |
| Jason Morton Deliveries Ltd | Transport & logistics | 2023 |
| Jazantay Stud Ltd | Agriculture & fishing | 2022 |
| JC Electrical Services (Durham) Ltd | Construction | 2025 |
| Jcal Installations Ltd | Construction | 2020 |
| Jchef Limited | Hospitality | 2022 |
| JDF Project Management Limited | Construction | 2011 |
| Jeff Cooper Limited | Wholesale & retail | 2005 |
| Jefferson Transport Ltd | Transport & logistics | 2013 |
| Jeffrey Estates Limited | Real estate | 2017 |
| JEL Groundworks NE Limited | Construction | 2022 |
| Jepa Properties Limited | Real estate | 2025 |
| JF Independent Social Work Limited | Health & social care | 2016 |
| JG Financial Limited | Professional & scientific | 2020 |
| JH & C Limited | Agriculture & fishing | 2013 |
| JH Roofing and Cladding Specialists Ltd | Construction | 2026 |
| Jigsaw AEP Ltd | Education | 2025 |
| JJ Groundworks (Northern) Limited | Construction | 2014 |
| JJ Steelwork Ltd | Manufacturing | 2025 |
| JK & CE Farming Limited | Agriculture & fishing | 2009 |
| JL Freehold Management Limited | Extraterritorial | 2009 |
| JL Health & Aesthetics Limited | Health & social care | 2019 |
| JLB Consultancy & Services Ltd | Professional & scientific | 2025 |
| JLW Utilities Ltd. | Energy | 2011 |
| JM Davies Projects Limited | Construction | 2008 |
| JM Industries North East Limited | Construction | 2025 |
| JM Joinery Services (NE) Ltd | Construction | 2018 |
| JMS Land and Developments Limited | Real estate | 2022 |
| JMS Properties NE Ltd | Real estate | 2021 |
| JMS Surveying Services Limited | Professional & scientific | 2015 |
| JMW Consulting Limited | Professional & scientific | 2023 |
| JMZ Medical Limited | Health & social care | 2014 |
| JNR Controls Ltd | Administrative & support | 2021 |
| JNR Enterprises Ltd | Professional & scientific | 2025 |