| Smartsys Technology Solutions Limited | Information & communication | 2024 |
| SMG Mechanical Solutions Ltd | Mining & quarrying | 2021 |
| SMG OFF Shore Ltd | Mining & quarrying | 2019 |
| Smith Coach Sales Ltd | Wholesale & retail | 2025 |
| Smith Housing Commercial Limited | Real estate | 2022 |
| Smith Housing Holdings Limited | Financial services | 2022 |
| Smith Housing Limited | Real estate | 2020 |
| Smith Housing Morpeth Ltd | Real estate | 2023 |
| Smithworks Golf Limited | Manufacturing | 2017 |
| Smokimaple Ltd | Real estate | 2026 |
| Snapback Joinery Limited | Construction | 2019 |
| Snapback Properties Ltd | Real estate | 2025 |
| Snorks Limited | Construction | 2019 |
| Sofra Lifts Ltd | Manufacturing | 2025 |
| Soleash Limited | Professional & scientific | 1989 |
| Solid Ethos Ltd | Information & communication | 2021 |
| Solus Media Ltd. | Information & communication | 2011 |
| Solveit Technical Engineers Limited | Information & communication | 2015 |
| Sonological Limited | Health & social care | 2015 |
| Soothesoul Ltd | Wholesale & retail | 2025 |
| South Road Freehold Limited | Administrative & support | 2004 |
| Spacesaverbeds Ltd. | Wholesale & retail | 2005 |
| Spark Consultants Ltd | Professional & scientific | 2026 |
| Sparton Civils Limited | Administrative & support | 2023 |
| Speak OUT Safe Ltd | Wholesale & retail | 2023 |
| Spectrum Business Consultants Limited | Professional & scientific | 2025 |
| Speedygroup Limited | Real estate | 1947 |
| Spiral Solar Panels Limited | Extraterritorial | 2009 |
| Springalex Ltd. | Wholesale & retail | 2008 |
| Sprinter Signs Ltd | Manufacturing | 2015 |
| Spritz Car Cleaning Ltd | Wholesale & retail | 2025 |
| Spurreli Ltd | Manufacturing | 2010 |
| Sqork Ltd | Information & communication | 2020 |
| SRS Civils Ltd | Administrative & support | 2018 |
| SRS Force Solutions Limited | Professional & scientific | 2024 |
| Ss&M Ltd | Hospitality | 2017 |
| ST Andrews House Limited | Households | 2000 |
| ST Margarets Place Management Limited | Households | 2026 |
| ST Nails Morpeth Ltd | Other services | 2025 |
| Stable Hub Limited | Agriculture & fishing | 2026 |
| Stacked Newcastle Ltd | Hospitality | 2016 |
| Staithes Lane Properties Limited | Real estate | 2016 |
| Stampbrick Limited | Households | 2004 |
| Stanage Press Limited | Information & communication | 2017 |
| Stanford Creative Limited | Arts & recreation | 2016 |
| Stanners Investments Limited | Real estate | 2009 |
| Stanners Specialised Services LLP | | 2009 |
| Stannington Estates Construction Ltd | Construction | 2014 |
| Stansby Medical and Reporting Limited | Health & social care | 2022 |
| Stansby Medical Limited | Health & social care | 2018 |
| Stantton Limited | Information & communication | 2015 |
| Stapleton Infrastructure Solutions Ltd | Information & communication | 2013 |
| Star Barber Morpeth Ltd | Other services | 2025 |
| Star International Enterprises Limited | Hospitality | 2010 |
| Stark Hartley Atkinson Limited | Administrative & support | 2007 |
| Stay PUT Properties Ltd | Real estate | 2005 |
| Steabler's Secure Staffing Services Ltd | Administrative & support | 2024 |
| Stela Holdings Limited | Financial services | 2022 |
| Stemazing Ltd | Professional & scientific | 2019 |
| Stemazingkids CIC | Education | 2020 |
| Sterbeg Investments Ltd | Hospitality | 2025 |
| Sterling Outcomes Limited | Administrative & support | 2012 |
| Steve Abrol Ltd | Wholesale & retail | 2005 |
| Steve and Andrew Limited | Hospitality | 2016 |
| Steve Mullin Mortgages Limited | Financial services | 2015 |
| Stevick Properties Ltd | Real estate | 2025 |
| Stewart Capital Group Ltd | Financial services | 2026 |
| Stewart Residential Investments Ltd | Real estate | 2026 |
| Stimulo Ltd | Administrative & support | 2013 |
| Stone Global Solutions Ltd | Professional & scientific | 2025 |
| Stonebee Limited | Construction | 2003 |
| Stonebee Travel Limited | Professional & scientific | 2000 |
| Stonehaven Place Ltd | Real estate | 2018 |
| Stonetech (NE) Ltd | Manufacturing | 2025 |
| Store at Your Door Ltd | Transport & logistics | 2021 |
| Storey & Edmondson (Builders) Limited | Construction | 2000 |
| Storey Management Limited | Real estate | 2020 |
| Stormont Flood Prevention Ltd | Professional & scientific | 2016 |
| Stormshield Windows & Conservatories Limited | Construction | 1996 |
| Straight Forward Smiles Ltd | Health & social care | 2025 |
| Streamed Limited | Health & social care | 2021 |
| Stretchpower Contracts Limited | Extraterritorial | 2003 |
| Stripp Design Limited | Professional & scientific | 2021 |
| Strive Management Systems Ltd | Professional & scientific | 2025 |
| Structer Ltd | Construction | 2025 |
| Stuart Dunn Limited | Information & communication | 2013 |
| Stuart Wiggins Ltd | Information & communication | 2012 |
| Studio Tinsley Ltd | Arts & recreation | 2018 |
| Sturton Grange Management Company Ltd | Households | 2021 |
| Successful Consulting Ltd | Education | 2013 |
| Successful Training Limited | Education | 2015 |
| Suitcases Baby Limited | Administrative & support | 2022 |
| Sullivan Associates Ltd. | Professional & scientific | 2012 |
| Sumobility Limited | Information & communication | 2022 |
| Sunlight Properties NE Ltd | Real estate | 2020 |
| Sunshine Pre-School (Morpeth) Ltd | Education | 2019 |
| Superior Paint Protection Ltd | Wholesale & retail | 2020 |
| Swarland Park Equestrian Limited | Agriculture & fishing | 2022 |
| Sweet N Sourdough Ltd | Wholesale & retail | 2026 |
| Sweetbriar Developments Ltd | Construction | 2021 |