| Smellz Limited | Manufacturing | 2026 |
| Smithburn Joinery and Construction Ltd | Construction | 2023 |
| Smithg Limited | Wholesale & retail | 2025 |
| Smiths Decorators Ltd. | Construction | 2016 |
| Smmz Holdings Limited | Financial services | 2026 |
| Smokefree Limited | Other services | 2019 |
| Smooth Cuts Company Limited | Other services | 2026 |
| Smurfs DH7 Ltd | Hospitality | 2025 |
| Snack-It Ltd | Hospitality | 2025 |
| Sneb Limited | Real estate | 2020 |
| Sneddon and Richardson Limited | Construction | 1964 |
| Snippr Ltd | Information & communication | 2022 |
| Snowdon & Wallace Groundworks Ltd | Construction | 2019 |
| SO & BE Ltd | Hospitality | 2025 |
| Soaring Birds Coaching Ltd | Education | 2023 |
| Sobbe Trade Consulting Ltd | Wholesale & retail | 2025 |
| Soccarena Holdings Limited | Financial services | 2010 |
| Soccarena Limited | Arts & recreation | 2000 |
| Social Co Holdings Limited | Real estate | 2021 |
| Social Explosion Limited | Professional & scientific | 2018 |
| Social Jump Limited | Information & communication | 2025 |
| Social Return Case Management Limited | Health & social care | 2014 |
| Society of the Sacred Mission | Other services | 2003 |
| Soco Investment Group Limited | Financial services | 2024 |
| Softglobe Ltd | Information & communication | 2025 |
| Softwarecrab Limited | Information & communication | 2023 |
| Solar Glow Sunbed Hire Ltd | Administrative & support | 2025 |
| Solder Buddy Ltd | Manufacturing | 2026 |
| Solid Capital Limited | Real estate | 2014 |
| Solrae Limited | Professional & scientific | 2019 |
| Someplace Else Ltd | Manufacturing | 2018 |
| Somers Rope Access Solutions Ltd | Construction | 2012 |
| Sondar Print Solutions Limited | Manufacturing | 2014 |
| Sop.Ai Limited | Information & communication | 2026 |
| Sophie Clothier Ltd | Professional & scientific | 2024 |
| Soproduction Limited | Professional & scientific | 2024 |
| Sorin Properties Limited | Real estate | 2025 |
| Soul Solutions Consultancy Ltd | Professional & scientific | 2025 |
| Sound Power Limited | Professional & scientific | 1995 |
| South Street Investments(Durham) Ltd | Financial services | 2024 |
| South Street Limited | Real estate | 2025 |
| South Tyneside Smartzone Limited | Transport & logistics | 2015 |
| Southerndreams Investments (Private) Limited | Administrative & support | 2019 |
| Southview Investments NE Limited | Real estate | 2019 |
| Souvenir Productions Ltd | Hospitality | 2015 |
| Souvenir Scenic Studios Ltd. | Arts & recreation | 1994 |
| Sowerby Build Group Ltd | Construction | 2025 |
| SP Engineering Group Limited | Construction | 2026 |
| Sp-Premii Ltd | Manufacturing | 2025 |
| Span Estates Limited | Real estate | 2023 |
| Spark Renewable Energy Investments Ltd | Financial services | 2022 |
| Sparke Energy Management Ltd | Administrative & support | 2026 |
| Spartan Access Limited | Construction | 2016 |
| Spartan AI Limited | Information & communication | 2026 |
| Spec J Motor Sport Limited | Wholesale & retail | 2024 |
| Special Branch Tree Services NE Ltd | Agriculture & fishing | 2022 |
| Spectrum Vision Ltd | Health & social care | 2024 |
| Specular World Ltd | Professional & scientific | 2017 |
| Speed 8767 Limited | Real estate | 2001 |
| Spelk Studio Limited | Professional & scientific | 2022 |
| Spenny Hand Car Wash Ltd | Wholesale & retail | 2023 |
| Sphere 32 Limited | Other services | 2021 |
| Spice Girls Ingredients Ltd | Wholesale & retail | 2023 |
| Spiers Software Services Ltd | Information & communication | 2021 |
| Spingate Consulting Limited | Professional & scientific | 2019 |
| Spingate Investment Management Limited | Professional & scientific | 2000 |
| Spinnaker Property Ltd | Real estate | 2016 |
| Spinnovate Ltd | Professional & scientific | 2022 |
| Spotty Media Limited | Professional & scientific | 2016 |
| SPP Rail Limited | Construction | 2024 |
| Sprig & Story Ltd | Education | 2025 |
| Sproates Capital Holdings Limited | Financial services | 2026 |
| SPS Homes Ltd | Construction | 2022 |
| SPV2 by JHJ Ltd | Real estate | 2026 |
| SQM Estates Limited | Real estate | 2016 |
| Squiggy Design & Distribution Ltd | Wholesale & retail | 2025 |
| Squire Distribution Services Limited | Transport & logistics | 1977 |
| SR Technology Innovations Ltd | Professional & scientific | 2010 |
| SRG Electrical Compliance Services Ltd | Construction | 2021 |
| SRG Facilities Management Ltd | Administrative & support | 2022 |
| SRI Kanaparthy Limited | Health & social care | 2009 |
| SRI Vijaya Venkata LLP | | 2012 |
| Srla Limited | Professional & scientific | 2017 |
| SRT Shopping Limited | Wholesale & retail | 2024 |
| SS Commercial Solutions Limited | Administrative & support | 2022 |
| SS Construction (NE) Ltd | Construction | 2017 |
| Ssaykun Home Ltd | Wholesale & retail | 2025 |
| SSD Business Consulting Limited | Professional & scientific | 2020 |
| Sshg Limited | Construction | 2007 |
| SSS Collection's Ltd | Wholesale & retail | 2024 |
| Sstaz Properties Limited | Real estate | 2020 |
| ST Anne's Limited | Households | 2000 |
| ST Godrics Court Limited | Households | 2000 |
| ST James Close South Charlton Ltd | Households | 2025 |
| ST. Giles Filling Station Ltd | Wholesale & retail | 2008 |
| Stacked and Smashed Ltd | Hospitality | 2025 |
| Stamford Plumbing Group Ltd | Financial services | 2024 |
| Stampflat Limited | Real estate | 2004 |
| Stan Lumsden Bespoke Ltd | Manufacturing | 2022 |
| Stanley Learning Partnership | Education | 2016 |