| Studio Stassen Ltd | Professional & scientific | 2024 |
| Studio Structure Holdings Ltd | Financial services | 2025 |
| Studio Structure Properties Ltd | Real estate | 2025 |
| Studio Stuart Palmer Ltd | Professional & scientific | 2025 |
| Study Atlas Limited | Information & communication | 2016 |
| Studybyte Ltd | Education | 2025 |
| Stupor Films Ltd | Information & communication | 2022 |
| Sturton Grange Developments Limited | Construction | 2001 |
| Styled by Rossey Ltd | Wholesale & retail | 2025 |
| Styler Digital Ltd | Information & communication | 2020 |
| Stylexpat Limited | Wholesale & retail | 2025 |
| Stylingh Ltd | Wholesale & retail | 2023 |
| Styluxe Ltd | Wholesale & retail | 2025 |
| SUB Central Limited | Hospitality | 2020 |
| SUB Durham-Tees Limited | Hospitality | 2020 |
| SUB Experts Limited | Hospitality | 2026 |
| SUB North Tyneside Limited | Hospitality | 2020 |
| Sub-Sea Energy (NCL) Ltd | Professional & scientific | 2015 |
| Sub-Sea Power Services Limited | Construction | 2026 |
| Subha Retails Ltd | Wholesale & retail | 2025 |
| Submerged Solutions Limited | Professional & scientific | 2023 |
| Subport (NE) Limited | Construction | 2020 |
| Subsidio Limited | Real estate | 2025 |
| Suburban Homes Limited | Real estate | 1963 |
| Suburban Inns Management Limited | Professional & scientific | 2017 |
| Success Bidco 2 Limited | Financial services | 2016 |
| Suchure Ltd | Information & communication | 2026 |
| Suda Security Ltd | Administrative & support | 2021 |
| Suda Taxis Ltd | Transport & logistics | 2026 |
| Sudanese Food Corner Ltd | Hospitality | 2026 |
| Sudanese Youth Ltd | Education | 2022 |
| SUE Bowman Consulting Ltd | Information & communication | 2012 |
| SUE Hastie Solutions Limited | Professional & scientific | 2010 |
| Sue's Designs Ltd | Manufacturing | 2025 |
| Suffresh Ltd | Hospitality | 2024 |
| Sugarbucks Ltd | Wholesale & retail | 2025 |
| Sugarcoat Technologies Ltd | Information & communication | 2019 |
| Sugley Maintenance Limited | Households | 2003 |
| Sukaina GSM Limited | Wholesale & retail | 2012 |
| Sukukfi Ltd | Information & communication | 2025 |
| Sulbah Ltd | Hospitality | 2021 |
| Sulco Ltd | Professional & scientific | 2024 |
| Sully's (NE) Limited | Hospitality | 2025 |
| Sultan & Group Ltd | Real estate | 2023 |
| Sultan Property Consultancy Ltd | Real estate | 2022 |
| Sultan Property Holdings Ltd | Real estate | 2020 |
| Suman Consultancy Limited | Health & social care | 2022 |
| Sumeria Health Ltd | Professional & scientific | 2024 |
| Sumeria Healthcare Ltd | Health & social care | 2023 |
| Sumi Properties Limited | Real estate | 2022 |
| Summer House 2025 Limited | Hospitality | 2022 |
| Summerdale House Property Management Company Limited | Real estate | 2004 |
| Summerhill Fruit and VEG Limited | Wholesale & retail | 2014 |
| Summerhill Investments NE Limited | Real estate | 2025 |
| Summerhill Trust Ltd | Health & social care | 2010 |
| Summerhill View Management Company Limited | Households | 2022 |
| Summers-Inman Construction and Property Consultants LLP | | 2002 |
| Summit Bridge M & a Ltd | Professional & scientific | 2025 |
| Summit Crazy Ltd | Manufacturing | 2019 |
| Summit Mrcog Ltd | Education | 2025 |
| Summit North Ltd | Professional & scientific | 2025 |
| Summit UK Holdings Limited | Manufacturing | 2026 |
| Sumo Marketing Group Limited | Professional & scientific | 2019 |
| Sumus Education Limited | Administrative & support | 2019 |
| Sun Gardens Management Company Limited | Real estate | 2005 |
| Sun Inn Morpeth Limited | Hospitality | 2014 |
| Sundara Pharmaceuticals Ltd | Professional & scientific | 2018 |
| Sunday Citizen UK Ltd | Manufacturing | 2025 |
| Sunday Girl Floral Ltd | Wholesale & retail | 2023 |
| Sunday Retreat Ltd | Wholesale & retail | 2024 |
| Sunderland Hand Car Wash and Valeting Ltd | Other services | 2015 |
| Sunderland Hotels Limited | Hospitality | 2009 |
| Sunderland Rope and Rigging Ltd | Construction | 2021 |
| Sungold Autosounds Limited | Wholesale & retail | 1982 |
| Sungshine Ltd | Real estate | 2015 |
| Suni Software Ltd | Information & communication | 2010 |
| Sunlak Ltd | Other services | 2017 |
| Sunna Travel and Tours Ltd | Real estate | 2016 |
| Sunnah Detox Ltd | Health & social care | 2025 |
| Sunningdale (Ryton) Management Limited | Real estate | 2002 |
| Sunniside Café Ltd | Wholesale & retail | 2023 |
| Sunniside Car Sales Ltd | Wholesale & retail | 2014 |
| Sunniside Healthcare Limited | Wholesale & retail | 2011 |
| Sunniside Interiors by LKC Limited | Construction | 2019 |
| Sunniside Roofing & Cladding Ltd | Construction | 2022 |
| Sunny Jesmond Italian Ltd | Hospitality | 2025 |
| Sunrise Takeaway Limited | Hospitality | 2005 |
| Sunsbury Ltd | Real estate | 2024 |
| Sunset Studios Limited | Arts & recreation | 2019 |
| Sunshine Dental Services Limited | Health & social care | 2016 |
| Sunshine Dining Ltd | Hospitality | 2026 |
| Sunshine Realisations Limited | Manufacturing | 1997 |
| Sunshine Restaurant NCL Ltd. | Hospitality | 2024 |
| Sunyee Properties Limited | Real estate | 2024 |
| Supanaught Ltd | Professional & scientific | 2010 |
| Super Accountants Ltd | Professional & scientific | 2025 |
| Super Duper Real Estate Limited | Real estate | 2020 |
| Super Shines Hand Car Wash Ltd | Wholesale & retail | 2018 |
| Super Soft Ices Ltd | Hospitality | 2023 |
| Supercyn Care Ltd | Health & social care | 2022 |