| South Burns Tandoori Ltd | Hospitality | 2020 |
| Southchurch Mews RTM Ltd | Households | 2021 |
| Southhill Farm Services Ltd | Administrative & support | 2010 |
| SP Auto Move Ltd | Wholesale & retail | 2025 |
| Spark Pathways Limited | Health & social care | 2026 |
| Spartan Construction Management Limited | Construction | 2017 |
| Speed Car Detailing Ltd | Administrative & support | 2025 |
| Spenkad Holdings Ltd | Financial services | 2026 |
| Spicecrm Limited | Information & communication | 2025 |
| Spirit Integrated Systems Ltd | Manufacturing | 2012 |
| SPL Analytics Limited | Information & communication | 2021 |
| Springfield Townhouses Limited | Households | 2015 |
| Springs Roofing Limited | Construction | 1985 |
| Sprout People Solutions Limited | Professional & scientific | 2025 |
| Squareacres Land Development Limited | Real estate | 2016 |
| ST. Joseph EYE Service Limited | Health & social care | 2025 |
| Staff Power Group (NE) Ltd | Administrative & support | 2021 |
| Staffvetting.Com Limited | Information & communication | 2007 |
| Stanley Florence Ltd | Hospitality | 2025 |
| Station Tyres & Auto Ltd | Wholesale & retail | 2025 |
| Stay at Home Care Limited | Public administration | 2025 |
| Steel City (Dore) Ltd | Construction | 2021 |
| Steel City Fulwood Ltd | Construction | 2024 |
| Steel City Holdco Ltd | Financial services | 2021 |
| Steel City Totley Ltd | Construction | 2021 |
| Stella Coatings Limited | Professional & scientific | 2016 |
| Stella Crafts Limited | Wholesale & retail | 2026 |
| Stephen Graham Brickwork Limited | Construction | 2019 |
| Stephen Hocking Utility Services Ltd | Energy | 2019 |
| Stephen Joyce Wealth Management Limited | Financial services | 2009 |
| Steve Copp Carpets Ltd | Wholesale & retail | 2025 |
| Steven W Davies Ltd | Hospitality | 2015 |
| STL Awards Ltd | Administrative & support | 2026 |
| Stokes Engagement & Project Services Limited | Professional & scientific | 2025 |
| Stone and Key Property Management Ltd | Real estate | 2026 |
| Storey Board Limited | Hospitality | 2024 |
| Streamlinecart Solutions Ltd | Wholesale & retail | 2024 |
| Stroke IT Design Limited | Manufacturing | 2012 |
| Strongher Studio Ltd | Arts & recreation | 2025 |
| Studio Structure (South East) Ltd | Professional & scientific | 2023 |
| Studio Structure Ltd | Professional & scientific | 2020 |
| Studiodmc Limited | Professional & scientific | 2015 |
| Style Barbers Birtley Ltd | Other services | 2024 |
| Sun Tanning Co CLS Limited | Other services | 2024 |
| Sunderland Hockey Club Limited | Arts & recreation | 2024 |
| Super Mario Property Bros Limited | Real estate | 2026 |
| Suppression and Harness Solutions Ltd | Manufacturing | 2023 |
| SW Joinery and Construction Ltd | Construction | 2025 |
| Sweet & Swirl Ltd | Hospitality | 2026 |
| Swift Gifts Limited | Wholesale & retail | 2018 |
| Swift Stage Ltd | Professional & scientific | 2025 |
| Sycamore Property Developments Limited | Construction | 2001 |
| Synapticare Solutions Ltd | Information & communication | 2025 |
| Synq Automation Ltd | Information & communication | 2026 |
| Synthflo Technologies UK Ltd | Construction | 2021 |
| Systim Consultancy Limited | Professional & scientific | 2017 |
| T & H Sales Ltd | Wholesale & retail | 2024 |
| T & P Property Solutions Limited | Real estate | 2024 |
| T C Home Improvements Limited | Construction | 2015 |
| T-Squared Validair Limited | Professional & scientific | 1989 |
| T.Parker Plumbing and Heating Services Ltd | Construction | 2021 |
| T.W. Trades (North East) Ltd | Construction | 2017 |
| T4 Beauty Ltd | Other services | 2025 |
| Tainted Ltd | Administrative & support | 2019 |
| TAJ Property Leasing's Limited | Real estate | 2020 |
| Tanfield Manor Stables Limited | Extraterritorial | 2015 |
| Taotech (UK) Limited | Transport & logistics | 2009 |
| Tarian Risk Management Ltd | Administrative & support | 2024 |
| Taskforce Green Ltd | Education | 2022 |
| Taylor'D Tiles Ltd | Construction | 2021 |
| TC HI Ltd | Construction | 2020 |
| TCM Pubco Ltd | Hospitality | 2024 |
| Team Armstrong Limited | Professional & scientific | 2014 |
| TEAMGP24 Ltd | Hospitality | 2024 |
| TEAMHANLON25 Ltd | Hospitality | 2025 |
| TEC Roofing and Building Services Limited | Construction | 2013 |
| Tech 2001 Limited | Construction | 2014 |
| Tech Unicorn Global Limited | Information & communication | 2018 |
| TECH4CASH Ltd | Wholesale & retail | 2021 |
| Techlaser Ltd | Other services | 2005 |
| Technical Training Associates Ltd | Extraterritorial | 2022 |
| Technology, Change and Cyber Risk Limited | Information & communication | 2025 |
| Techtegrity Limited | Information & communication | 2010 |
| Teclynx Ltd | Information & communication | 2020 |
| Teichman Park Ltd | Professional & scientific | 2015 |
| Tempwise Heating Solutions Ltd | Construction | 2025 |
| TFS Plumbing and Heating Limited | Construction | 2021 |
| THE Advisory Group UK Limited | Professional & scientific | 2021 |
| THE Angel Wellness Centre Salon Ltd | Other services | 2025 |
| THE Big Swing NE Ltd | Arts & recreation | 2025 |
| THE Book Gadgie Ltd | Wholesale & retail | 2026 |
| THE Bridal Sewing Rooms Ltd | Manufacturing | 2019 |
| THE Brighton HUT Company Ltd | Professional & scientific | 2017 |
| THE Cage Airsoft Limited | Wholesale & retail | 2015 |
| THE Carbon Interface Ltd | Information & communication | 2020 |
| THE Carriages Durham Limited | Households | 2018 |
| THE Castle Games Events Ltd | Arts & recreation | 2017 |
| THE Cherrytree Ouston Ltd | Hospitality | 2013 |
| THE Cleaning Company North Ltd | Administrative & support | 2018 |
| THE County Durham Cleaning Company CIC | Administrative & support | 2023 |