| Ivory Industrial Solutions Limited | Professional & scientific | 2024 |
| J L M Construction and Maintenance Ltd | Construction | 2025 |
| J W G (NE) Ltd | Hospitality | 2018 |
| J&J Dixon Holdings Ltd | Financial services | 2023 |
| J. S. Lowry Eyecare Limited | Health & social care | 2010 |
| J.A.L. Resources Ltd | Professional & scientific | 2026 |
| JAC JLC Ltd | Health & social care | 2023 |
| Jackdale Electricals Ltd | Construction | 2023 |
| JAM Ross Logics Ltd | Transport & logistics | 2025 |
| Jamie Ahmed & Co Ltd | Professional & scientific | 2025 |
| Japanese Performance & Nostalgia Ltd | Wholesale & retail | 2023 |
| Jarrow and Hebburn Athletic Club Ltd | Arts & recreation | 2017 |
| Jarrow Carpet Warehouse Limited | Wholesale & retail | 2007 |
| Jarrow Coachworks Limited | Manufacturing | 2005 |
| Jarrow European Mini Market Ltd | Wholesale & retail | 2025 |
| Jarrow JK Limited | Other services | 2012 |
| Jarrow MOT Centre Limited | Wholesale & retail | 2004 |
| Jarrow School Trust | Education | 2010 |
| Jarrow ST. Paul's Church (Shop) Limited | Wholesale & retail | 1994 |
| Jason John Potts Limited | Transport & logistics | 2018 |
| JAW Management LLP | | 2025 |
| JBT CCT Ltd | Other services | 2019 |
| JC Blade Repair Ltd | Manufacturing | 2026 |
| JCS Storage and Hire Services Ltd | Transport & logistics | 2017 |
| JD Access Ltd | Construction | 2023 |
| JD Eljay Ltd | Professional & scientific | 2023 |
| JD Plumbing Services Ltd | Construction | 2024 |
| JDB Properties (NE) Ltd | Real estate | 2024 |
| Jenners Catering Wearside Ltd | Hospitality | 2022 |
| Jesmond Place Management Limited | Households | 1992 |
| Jessica Jade Limited | Administrative & support | 2025 |
| JF Access Ltd | Other services | 2023 |
| JG Investments Group Limited | Wholesale & retail | 2025 |
| JJ Dixon Ltd | Financial services | 2023 |
| JJ Skincare Limited | Health & social care | 2025 |
| JJ1 Properties Limited | Real estate | 2026 |
| JK Commercial Savings Ltd | Administrative & support | 2025 |
| JK Schoolwear and Workwear Ltd | Wholesale & retail | 2013 |
| JKL Couriers Ltd | Transport & logistics | 2023 |
| JLD Civils & Groundworks Ltd | Construction | 2023 |
| JLS Maintenance Ltd | Professional & scientific | 2026 |
| JLW Fabrication Ltd | Other services | 2016 |
| JM Balance Books Ltd | Professional & scientific | 2024 |
| JMW Merchandising Limited | Construction | 2026 |
| Johndkpaint Ltd | Construction | 2024 |
| Jordan Heron Ltd | Health & social care | 2025 |
| JP Exterior Solutions Ltd | Construction | 2026 |
| JP Safety Ltd | Professional & scientific | 2017 |
| JR Electrical (NE) Limited | Construction | 2021 |
| JR MRF Holdings Ltd | Financial services | 2025 |
| JTC Retail Ltd | Wholesale & retail | 2022 |
| Just Business Group Ltd | Professional & scientific | 2016 |
| Jwareham Ltd | Manufacturing | 2025 |
| JWP Contracting Ltd | Construction | 2024 |
| J’S Gardening and Waste Removal Limited | Water & waste | 2026 |
| K & F Associates Limited | Professional & scientific | 2013 |
| K&A Plant Services Ltd | Manufacturing | 2024 |
| K1SUP Ltd | Hospitality | 2024 |
| KAI Cleaners Ltd | Administrative & support | 2013 |
| KAJ Universal Ltd | Professional & scientific | 2022 |
| KAL Logistics Ltd | Transport & logistics | 2026 |
| Kani Kebab Ltd | Wholesale & retail | 2017 |
| Kasaei Holdings Ltd | Real estate | 2018 |
| Kate Osborne Campaigns Limited | Other services | 2022 |
| KBH Projects Ltd | Professional & scientific | 2025 |
| KCH Construction Ltd | Professional & scientific | 2019 |
| KCP Freehold Management Company Limited | Real estate | 2012 |
| Kelnearshore Limited | Manufacturing | 2020 |
| KES Joinery and Property Services Limited | Construction | 2008 |
| Keystone Training Solutions Ltd | Information & communication | 2024 |
| Kieran M Industrial Ltd | Administrative & support | 2023 |
| Kiipwell Solutions Ltd | Real estate | 2026 |
| Kiss My Face Aesthetics Ltd | Other services | 2026 |
| Kjwf Ltd | Wholesale & retail | 2018 |
| KMK Engineering Ltd | Professional & scientific | 2006 |
| KN Housing Solutions Limited | Real estate | 2017 |
| Knoko Flooring Limited | Wholesale & retail | 2022 |
| Konsise Limited | Information & communication | 2018 |
| Korzwin Online Ltd | Wholesale & retail | 2022 |
| KP Rope Access Limited | Mining & quarrying | 2026 |
| KP Simpson Holdings Ltd | Financial services | 2022 |
| KP Simpson Ltd | Professional & scientific | 2012 |
| Kpottswelding Ltd | Construction | 2025 |
| Kristan Court RTM Company Limited | Real estate | 2013 |
| Ktgd&D Ltd | Real estate | 2022 |
| KW86 Ltd | Information & communication | 2025 |
| L Crooks Consulting Ltd | Information & communication | 2025 |
| Largo House Country Park Limited | Wholesale & retail | 2013 |
| Last Knight Management Limited | Professional & scientific | 2026 |
| Lasun Indian Cuisine Ltd | Hospitality | 2016 |
| LBR Business Support Ltd | Transport & logistics | 2025 |
| LCR Engineering Limited | Manufacturing | 2018 |
| Leadeducation Ltd | Education | 2016 |
| Leebos Construction Ltd | Construction | 2023 |
| Lenny's Pool Hall Ltd | Arts & recreation | 2024 |
| LHV Power Networks Ltd | Construction | 2024 |
| Libra Seafood Processing Limited | Manufacturing | 2002 |
| Libra Seafoods Limited | Wholesale & retail | 2002 |
| Life Phorce Ltd | Professional & scientific | 2011 |
| Livecops Ltd | Information & communication | 2021 |