| ST Johns Kitchen Ltd | Hospitality | 2018 |
| ST. Cuthberts Court Limited | Real estate | 2007 |
| Steven James Guitars Limited | Wholesale & retail | 2006 |
| Stockton Football & Cricket Club | Arts & recreation | 2025 |
| Susan Carol Independent Social Work Services Limited | Health & social care | 2023 |
| Sword Books Limited | Information & communication | 2013 |
| Tanni Grey-Thompson Ltd | Professional & scientific | 2006 |
| Tetra Real Estate Limited | Construction | 2012 |
| THE Amelia Edit Ltd | Professional & scientific | 2025 |
| THE Internet BED Co Ltd. | Wholesale & retail | 2011 |
| THE Lighthouse Vision Ltd | Information & communication | 2024 |
| THE Sock Sensation Ltd | Wholesale & retail | 2025 |
| THE Wigley Group Limited | Construction | 1964 |
| THE Wumi Limited | Hospitality | 2025 |
| Tk's Cafe and Catering Services Ltd | Hospitality | 2018 |
| TM Rigging and Lifting Ltd | Other services | 2021 |
| Tony Brannon Creative Limited | Professional & scientific | 2019 |
| Triggerglen Limited | | 1983 |
| Twin Services Limited | Construction | 1982 |
| Tyto Contracting Limited | Construction | 2017 |
| Ukinkers Limited | Information & communication | 2022 |
| Virtus Property Services Limited | Administrative & support | 2007 |
| Welfare Solutions Limited | Administrative & support | 2023 |
| Wigley (UK) Limited | Real estate | 1963 |
| Wigley Connect Ltd | Administrative & support | 2024 |
| Wigley Strategic Land Limited | Construction | 2014 |
| Wigleys Overseas Limited | Extraterritorial | 1995 |
| YOU Knead Pizza Ltd | Hospitality | 2020 |