| SH Food Services Ltd | Hospitality | 2024 |
| Sharpsmart Limited | Water & waste | 2001 |
| Shaun Davies Ltd | Construction | 2016 |
| Shimmy Books Limited | Other services | 2024 |
| Shopex Trade Ltd | Wholesale & retail | 2026 |
| Silva Narciso Ltd | Professional & scientific | 2024 |
| Simon Taylor Joinery Limited | Construction | 2022 |
| Simply Blooms Floristry & Workshops Ltd | Administrative & support | 2021 |
| Simply Stripes the Signmakers Ltd. | Manufacturing | 1999 |
| Sjbfitness Ltd | Other services | 2026 |
| SL Business Developments Limited | Real estate | 2018 |
| Smith & Goodwin Ltd | Construction | 2014 |
| Solid Surface NE Limited | Manufacturing | 2010 |
| Somtree Ltd | Real estate | 2022 |
| Sonatek Ltd | Wholesale & retail | 2025 |
| Sophie Nails & Spa Ltd | Other services | 2022 |
| Sorrento Consultancy Services Ltd | Professional & scientific | 2023 |
| Soulstep Ltd | Wholesale & retail | 2025 |
| SP Fortune Limited | Hospitality | 2026 |
| Spa Dispatch Limited | Wholesale & retail | 2022 |
| SPD Financial Ltd | Professional & scientific | 2020 |
| SPD Wills & Trusts Limited | Professional & scientific | 2023 |
| Specialists Leak Detection Ltd | Construction | 2023 |
| Spencers Plastering Solutions Ltd | Construction | 2025 |
| Spenny Supermarket Ltd | Real estate | 2019 |
| Spennymoor Foot Clinic Limited | Health & social care | 2024 |
| Spennymoor Town FC Ltd. | Arts & recreation | 2003 |
| Spennymoor Town Youth Football Club CIC | Arts & recreation | 2025 |
| Spennytech Limited | Information & communication | 2021 |
| Splash Innovations Limited | Extraterritorial | 2011 |
| Spragg's MOT & Autocare Limited | Wholesale & retail | 2024 |
| Square Flag Limited | Wholesale & retail | 2022 |
| SRD ENG Consultancy Limited | Professional & scientific | 2026 |
| ST. Oswins (Tynemouth) Management Company Limited | Households | 2002 |
| ST. Pauls (Spennymoor) Centre Limited | Hospitality | 2008 |
| Stanland Transport & Storage Solutions Limited | Transport & logistics | 2017 |
| Stanners Farm Agriculture Ltd | Agriculture & fishing | 2024 |
| Stanners Farm Equine Limited | Agriculture & fishing | 2021 |
| Staydryroofing & Gutters Ltd | Construction | 2025 |
| Steel Catering Trailers Ltd | Manufacturing | 2023 |
| Stem Consulting Ltd | Professional & scientific | 2023 |
| Stephen Sawley Transport Limited | Transport & logistics | 2000 |
| Stephen Vasey Consulting Limited | Information & communication | 2019 |
| Stepping Stone Training Ltd | Education | 2025 |
| Stogdale Technology Limited | Information & communication | 2018 |
| Stopera Ltd | Wholesale & retail | 2026 |
| Storey Inspection Ltd. | Professional & scientific | 2011 |
| Style Code Shopping Ltd | Wholesale & retail | 2019 |
| Subhandar Ltd | Wholesale & retail | 2025 |
| SUE Scott Guitars Limited | Manufacturing | 2015 |
| Sultn Ltd | Wholesale & retail | 2025 |
| Sunmorrow Ltd | Wholesale & retail | 2026 |
| Sunny Fortune Limited | Hospitality | 2023 |
| Sure Energy Savings Limited | Energy | 2019 |
| Surtees Management Services Limited | Real estate | 1990 |
| Swanova Ltd | Wholesale & retail | 2026 |
| Swim Quest North East Ltd | Education | 2018 |
| Sygnum Global Limited | Information & communication | 2026 |
| SYS Trade Ltd | Wholesale & retail | 2025 |
| Szwedpol. Ltd | Construction | 2024 |
| T&H Heating Solutions Ltd | Construction | 2023 |
| T.M. Nursery Enterprises Limited | Health & social care | 2003 |
| T.P. Enterprises Limited | Professional & scientific | 1986 |
| Tamper Security Systems Ltd | Administrative & support | 2025 |
| Tansel Yorukcu Ltd | Wholesale & retail | 2025 |
| Tasty Vape Spennymoor Ltd. | Wholesale & retail | 2020 |
| TAY Sports Ltd | Wholesale & retail | 2019 |
| Taylor Kidd Ltd | Wholesale & retail | 2021 |
| Taylor Packaging (Bishop Auckland) Limited | Wholesale & retail | 2002 |
| Taypac Limited | Professional & scientific | 1983 |
| TB Consultants (Recruitment) Ltd | Administrative & support | 2012 |
| Team Contracts UK Ltd | Manufacturing | 2014 |
| Teesdale GAS Ltd | Wholesale & retail | 2021 |
| Teksan Trade Ltd | Wholesale & retail | 2025 |
| Temel Collective Ltd | Wholesale & retail | 2026 |
| Temel Mobile Barbers Limited | Other services | 2020 |
| Terrapin Space Ltd | Professional & scientific | 2025 |
| TGR Housing Limited | Real estate | 2024 |
| TH Property and Investments Ltd | Real estate | 2026 |
| Thatchu Convenience Ltd | Wholesale & retail | 2026 |
| Thaya K Ltd | Wholesale & retail | 2023 |
| THE AXE House Limited | Arts & recreation | 2019 |
| THE Bounce House (NE) Ltd | Arts & recreation | 2019 |
| THE Brand Nerd Limited | Professional & scientific | 2024 |
| THE Cross Keys (ESH) Limited | Hospitality | 2018 |
| THE Daniels Corporation International Limited | Water & waste | 2000 |
| THE Day Centre Ltd | Real estate | 2019 |
| THE Decanter Drinks Company Limited | Wholesale & retail | 2018 |
| THE Destined Homes Limited | Real estate | 2025 |
| THE Durham Mining Museum | Arts & recreation | 2000 |
| THE Gourmet Group Limited | Wholesale & retail | 2013 |
| THE Green Room @ Top HAT Studios Limited | Hospitality | 2023 |
| THE Healthy Living Lounge Limited | Health & social care | 2025 |
| THE House of Eden Online Ltd | Wholesale & retail | 2020 |
| THE Little TAP Ltd | Hospitality | 2020 |
| THE Modern Samurai Ltd | Wholesale & retail | 2022 |
| THE MUM Collective Limited | Wholesale & retail | 2022 |
| THE New Volti Ltd | Other services | 2024 |
| THE Northern Workshop Ltd | Manufacturing | 2020 |
| THE Olive Moon Limited | Hospitality | 2020 |