| 00369704 Limited | | 1941 |
| 00648111 Limited | Extraterritorial | 1960 |
| 1 Skill AI Ltd | Information & communication | 2025 |
| 1 to 1 Technology Limited | Information & communication | 2000 |
| 10BRISTOL Limited | Professional & scientific | 2009 |
| 10X100 Ltd | Information & communication | 2022 |
| 110SERVICES NE Limited | Construction | 2025 |
| 121 Financial One Ltd | Financial services | 2002 |
| 123 Displays Limited | Other services | 2016 |
| 13 Russell Gardens Mews Limited | Hospitality | 2012 |
| 15530565 Ltd. | Transport & logistics | 2024 |
| 16 Finance Limited | Financial services | 2019 |
| 173 Grange Road RMA Ltd | Households | 2021 |
| 186 Investments Ltd | Construction | 2011 |
| 186 Property Solutions (Southern) Ltd | Construction | 1994 |
| 196 Whessoe Road Limited | Households | 2013 |
| 1ST Class Removals and Storage Ltd | Wholesale & retail | 2016 |
| 1ST Stop Logistics Limited | Transport & logistics | 2020 |
| 202 Specialist Operations Ltd | Administrative & support | 2026 |
| 2020 Creativ Ltd | Professional & scientific | 2021 |
| 21ST Century Rolling Stock Limited | Transport & logistics | 2018 |
| 21ST Century Steam Limited | Manufacturing | 2018 |
| 3 NDT Ltd | Professional & scientific | 2020 |
| 3 Park Villas Roundhay Limited | Households | 2003 |
| 3 Point Media Limited | Information & communication | 2014 |
| 3 Wire Heating Ltd | Construction | 2020 |
| 3 Wire Limited | Construction | 2007 |
| 3 Yellow Barrels Ltd | Wholesale & retail | 2020 |
| 30 Fernside Road Limited | Real estate | 2009 |
| 359 Norton Road RTM Company Limited | Households | 2012 |
| 36 Stanhope Road Management Company Limited | Real estate | 2009 |
| 360 Interactions Limited | Information & communication | 2019 |
| 396-406B North Road Management Limited | Households | 2010 |
| 3G Medical Limited | Health & social care | 2015 |
| 3K Industrial Blasting and Coating Services Ltd | Construction | 2023 |
| 3RD Hour Limited | Manufacturing | 2015 |
| 3S Accountancy Limited | Professional & scientific | 2003 |
| 3S Commercial Consulting Limited | Professional & scientific | 2016 |
| 3SM Investments Limited | Financial services | 2019 |
| 4 4 2 Media Group Limited | Professional & scientific | 2017 |
| 4 Clanricarde Gardens (Freehold) Limited | Households | 2017 |
| 4 Clanricarde Gardens Management Company Limited | Households | 1999 |
| 42 Ventures Group Ltd | Wholesale & retail | 2026 |
| 44 North Limited | Administrative & support | 1889 |
| 45 Financial Limited | Financial services | 2022 |
| 46180 Limited | Wholesale & retail | 2025 |
| 49 Parks Ltd | Professional & scientific | 2024 |
| 4D Darlington Limited | Real estate | 2015 |
| 4DP Ltd | Real estate | 2021 |
| 4MOTION Darlington | Arts & recreation | 2013 |
| 4REAL Media Ltd | Information & communication | 2017 |
| 5 Stars Barber Ltd | Other services | 2025 |
| 5 Stars Barber NE Limited | Other services | 2024 |
| 51 Heatherburn Court Ltd | Real estate | 2026 |
| 54 Legal Limited | Professional & scientific | 2025 |
| 5API Ltd | Real estate | 2026 |
| 5D Professional Services Limited | Professional & scientific | 2020 |
| 622 Ltd | Arts & recreation | 2018 |
| 65-91 Alverton Drive Freeholders Limited | Households | 2021 |
| 700 Club | Health & social care | 1996 |
| 7LOGIC Solutions Limited | Information & communication | 2015 |
| 7VEN Productions Ltd | Information & communication | 2020 |
| 81 North Architecture Ltd | Professional & scientific | 2025 |
| 81 North Interiors Ltd | Professional & scientific | 2024 |
| 8NORTH Property Ltd | Real estate | 2022 |
| 99 Main Street Limited | Real estate | 2026 |
| @Ivyhouse Salon Ltd | Other services | 2020 |
| A & J Coates Ltd | Other services | 2025 |
| A & N Supplies Ltd | Manufacturing | 2025 |
| A & T Highways Ltd | Construction | 2008 |
| A 2 Z MOT Ltd | Wholesale & retail | 2025 |
| A Bell & Sons Limited | Information & communication | 2017 |
| A D Recruitment Limited | Administrative & support | 2014 |
| A Gregory Building Contractors Limited | Construction | 2012 |
| A J Building & Roofing Supplies Limited | Wholesale & retail | 2015 |
| A J Convenience Store Limited | Wholesale & retail | 2013 |
| A N Willis Property Enterprises Limited | Real estate | 2026 |
| A O'Neill Ltd | Professional & scientific | 2018 |
| A Paterson Holdings Ltd | Transport & logistics | 2017 |
| A R Wilkinson Transport Ltd | Transport & logistics | 2026 |
| A Riozzi Telecommunications Limited | Information & communication | 2018 |
| A S & J K Leggott Limited | Agriculture & fishing | 2015 |
| A S M Surface Technologies Limited | Manufacturing | 2006 |
| A S Roofing and Cladding Ltd | Construction | 2024 |
| A Scaife Horse Shoeing Ltd | Administrative & support | 2020 |
| A Smith Projects Ltd | Professional & scientific | 2019 |
| A Star Attendance Solutions Ltd | Education | 2019 |
| A Star MOT Centre Ltd | Wholesale & retail | 2026 |
| A Star Northern Limited | Financial services | 2021 |
| A Star Scaffolding Ltd | Construction | 2012 |
| A V Finance Ltd | Financial services | 2020 |
| A Wake Joinery Ltd | Construction | 2023 |
| A Wood and SON Ltd | Administrative & support | 2021 |
| A&A Biotech Consultancy Ltd | Professional & scientific | 2025 |
| A&A IOW Ltd | Transport & logistics | 2026 |
| A&D Perry-Ryan Limited | Hospitality | 2025 |
| A&J Motors (Darlington) Ltd | Wholesale & retail | 2012 |
| A&K Masstore Ltd | Wholesale & retail | 2023 |
| A&N Teeside Ltd | Financial services | 2025 |
| A. Hurworth (N.E.) Limited | Financial services | 2025 |