| Hushedriver Ltd | Transport & logistics | 2025 |
| HW Psychology Ltd | Health & social care | 2025 |
| I.C.D. Electrical Contractors Limited | Construction | 2005 |
| IAM Here Express Ltd | Transport & logistics | 2024 |
| IAN Mitchell Ceremonies Ltd | Other services | 2013 |
| Ice Queeenz Ltd | Hospitality | 2026 |
| Ideas and Motion Ltd | Professional & scientific | 2025 |
| IEM 360 Ltd | Information & communication | 2019 |
| IEM 365 Ltd | Information & communication | 2021 |
| Ifind Financial Solutions Ltd | Financial services | 2017 |
| Ignis Plumb Ltd | Construction | 2024 |
| IJH UK Consultancy Limited | Professional & scientific | 2023 |
| Imaginable ME CIC | Education | 2025 |
| IMC Electrical Ltd | Construction | 2022 |
| IMH Consultancy Services Ltd | Professional & scientific | 2022 |
| Imperial Food Service Ltd | Hospitality | 2026 |
| IN Arnage Limited | Real estate | 2025 |
| In-Lines Heavy Lift Specialist Ltd | Construction | 2018 |
| Include Management Ltd | Information & communication | 2020 |
| Independent Financial Advice Bureau Limited | Financial services | 2010 |
| Indignant Arts Limited | Arts & recreation | 2025 |
| Indigo Topco Limited | Professional & scientific | 2009 |
| Indulgence Beauty and Tanning Ltd | Other services | 2023 |
| Infinite Homecare Ltd | Health & social care | 2020 |
| Inspections.Ndt Ltd | Administrative & support | 2014 |
| Interact Control Systems Ltd | Construction | 2017 |
| Interior Options NE Ltd | Construction | 2026 |
| Interplan Sign Systems Ltd | Administrative & support | 2002 |
| Investo-Form Properties Ltd | Real estate | 2025 |
| Iron Court Limited | Real estate | 2023 |
| Ironsmith Rigging Solutions Ltd | Professional & scientific | 2020 |
| Irugasa Group Ltd | Professional & scientific | 2012 |
| Irugasa Remote Control Systems Ltd | Manufacturing | 2000 |
| ISL Property Investments Ltd | Real estate | 2021 |
| Istanblue DH Ltd | Other services | 2026 |
| Istanblue Ltd | Other services | 2021 |
| J & C Coaches Limited | Transport & logistics | 2009 |
| J & K Brothers Limited | Real estate | 2026 |
| J Fife Book Keeping Limited | Professional & scientific | 2012 |
| J L Atherton Limited | Other services | 2017 |
| J Malone Limited | Extraterritorial | 2012 |
| J. & a. Moody Boiler Maintenance Limited | Other services | 1979 |
| J. Fryer & SON Limited | Construction | 2003 |
| J.F. Rigby Security Solutions Ltd | Administrative & support | 2025 |
| JA Rental Properties Ltd | Real estate | 2019 |
| Jaar Investment Properties Limited | Real estate | 2024 |
| JAB Rentals Limited | Real estate | 2022 |
| Jademay Consultancy Ltd | Administrative & support | 2025 |
| James a Mcneill Building & Civil Engineering Limited | Construction | 2003 |
| James Roofing Contractors Ltd | Construction | 2020 |
| James Rose Rentals Ltd | Real estate | 2023 |
| James Teasdale Ltd | Hospitality | 2021 |
| Jamuna Investments Ltd | Real estate | 2025 |
| Jamuna Stores Ltd | Wholesale & retail | 2020 |
| JAN Cook Wills and Trusts Ltd | Professional & scientific | 2023 |
| Jasmine RAI Productions Ltd | Information & communication | 2021 |
| JAY Networks Limited | Information & communication | 2024 |
| Jays Taxis Consett Limited | Transport & logistics | 2021 |
| Jays Taxis County Durham Ltd | Transport & logistics | 2024 |
| Jaystar Limited | Wholesale & retail | 2026 |
| JB Groundworks (North East) Limited | Administrative & support | 2022 |
| JCS (NE) Ltd | Administrative & support | 2022 |
| JCS (NW) Ltd | Wholesale & retail | 2022 |
| JD Paving Limited | Construction | 2014 |
| JE Robinson Plumbing & Heating Ltd | Energy | 2006 |
| Jecf Holdings Limited | Other services | 2023 |
| Jeffrey Dodds Electrical Engineers Limited | Construction | 1999 |
| Jewitt Arboriculture Ltd | Agriculture & fishing | 2025 |
| Jewitt Enterprises Limited | Financial services | 2016 |
| JFS NE Ltd | Manufacturing | 2010 |
| JG & RL Rentals Limited | Real estate | 2024 |
| JIA BAO Ltd | Hospitality | 2023 |
| JL Tree & Gardenworx NE Ltd | Administrative & support | 2026 |
| Jlev Properties Limited | Real estate | 2019 |
| JLP Construction North East Ltd | Construction | 2021 |
| Jlptfitness Ltd | Arts & recreation | 2026 |
| JM Woodlands Ltd | Agriculture & fishing | 2016 |
| JMC Digital Ltd | Information & communication | 2015 |
| Jmtr Contracting Ltd | Construction | 2025 |
| JP Groundworks (North East) Ltd | Construction | 2023 |
| Jp's Building & Restoration Ltd | Construction | 2023 |
| Jpdesign Kitchens Ltd | Professional & scientific | 2025 |
| Jpmg Properties Ltd | Real estate | 2025 |
| JSE Properties Ltd | Real estate | 2018 |
| Juality Limited | Other services | 1999 |
| Jula Crafts Limited | Wholesale & retail | 2013 |
| Just Meats (Northern) Limited | Financial services | 2016 |
| JWB Medical Ltd | Health & social care | 2019 |
| K & JT Services Limited | Professional & scientific | 2026 |
| K and P Group Ltd | Hospitality | 2026 |
| K D Inspections Ltd | Administrative & support | 2023 |
| K H Interior Design Limited | Construction | 2017 |
| K&D Bars Ltd | Hospitality | 2024 |
| K.A.E. Developments Limited | Real estate | 2020 |
| K.A.E. Inspection Limited | Professional & scientific | 2017 |
| K.D Design & Installations Ltd | Construction | 2018 |
| Kadirmany Ltd | Wholesale & retail | 2023 |
| Kair Products Limited | Wholesale & retail | 2024 |
| Katalist Services Limited | Information & communication | 2015 |
| Kathrine Glendenning Ltd | Households | 2025 |