| Sunderland Garden Limited | Hospitality | 2023 |
| Sunderland GAS Services Ltd | Construction | 2024 |
| Sunderland Golden Fish Ltd | Hospitality | 2024 |
| Sunderland GP Alliance Holding Company Limited | Financial services | 2018 |
| Sunderland GP Alliance Limited | Health & social care | 2014 |
| Sunderland Hand Car Wash (NE) Limited | Wholesale & retail | 2023 |
| Sunderland Harriers & Athletics Club | Arts & recreation | 2019 |
| Sunderland Healthcare Limited | Wholesale & retail | 2021 |
| Sunderland Home Care Associates (20-20) EBT Trustee Limited | Extraterritorial | 2017 |
| Sunderland Home Care Associates (20-20) Limited | Health & social care | 1998 |
| Sunderland Home Care Associates Ltd. | Health & social care | 1994 |
| Sunderland Home Grown CIC | Health & social care | 2015 |
| Sunderland Housing Service Ltd | Real estate | 2015 |
| Sunderland J Ltd | Hospitality | 2018 |
| Sunderland Leisure Limited | Real estate | 2012 |
| Sunderland Lgbt+ Network C.I.C. | Other services | 2015 |
| Sunderland LGV Driver Training Ltd | Education | 2012 |
| Sunderland Lifestyle Partnership Limited | Arts & recreation | 2015 |
| Sunderland Lighthouse Community Ltd | Education | 2015 |
| Sunderland LIT and Phil CIC | Administrative & support | 2026 |
| Sunderland Literacy AID C.I.C. | Education | 2018 |
| Sunderland Live Lobsters, Prawns and Fish Limited | Wholesale & retail | 1994 |
| Sunderland Love Nails Beauty Company Limited | Other services | 2019 |
| Sunderland Marina Ltd | Arts & recreation | 1996 |
| Sunderland Medical Ltd | Wholesale & retail | 2025 |
| Sunderland Music City CIC | Professional & scientific | 2025 |
| Sunderland Music, Arts and Culture Developments Limited | Construction | 2015 |
| Sunderland Music, Arts and Culture Trust | Arts & recreation | 2012 |
| Sunderland North Family Zone | Education | 2000 |
| Sunderland Office Furniture Ltd | Wholesale & retail | 2015 |
| Sunderland People First Co-Operative Community Interest Company | Health & social care | 2013 |
| Sunderland Property Buyers Ltd | Real estate | 2013 |
| Sunderland Railway Club Limited | Hospitality | 2023 |
| Sunderland RCA FC Ltd | Arts & recreation | 2015 |
| Sunderland RFC Limited | Arts & recreation | 2023 |
| Sunderland Shawarma Ltd | Hospitality | 2026 |
| Sunderland Trading Ltd | Wholesale & retail | 2025 |
| Sunderland Training & Education Farm Limited | Education | 2003 |
| Sunderland Tube-Fab Limited | | 1965 |
| Sunderland Van Sales Ltd | Wholesale & retail | 2019 |
| Sunderland Volunteer Life Brigade | Arts & recreation | 2003 |
| Sunderland Wall Outdoor Activities Ltd | Administrative & support | 2023 |
| Sunderland Wellness Project CIC | Other services | 2024 |
| Sunderland Young Peoples Bike Project Community Interest Company | Education | 2009 |
| Sunderland Youth and Community Orchestra CIC | Education | 2021 |
| Sundfood Limited | Hospitality | 2017 |
| Sunflower Lets Limited | Hospitality | 2023 |
| Sunland Mortgages Limited | Financial services | 2021 |
| Sunningdale Stores Ltd | Wholesale & retail | 2015 |
| Sunniside Deli Limited | Wholesale & retail | 2025 |
| Sunniside Heating Limited | Financial services | 2018 |
| Sunniside Manor Ltd | Hospitality | 2017 |
| Sunniside Studios Ltd | Administrative & support | 2021 |
| SUNRAY9 Ltd | Hospitality | 2025 |
| Sunrise Dessert Ltd | Hospitality | 2019 |
| Sunshine Co-Operative Community Interest Company | Wholesale & retail | 2016 |
| Sunter & Morris Ltd | Wholesale & retail | 2011 |
| SUNTONE618 Ltd | Extraterritorial | 2022 |
| Supastitch Newcastle Ltd | Wholesale & retail | 2017 |
| Supastitch Sunderland Ltd | Manufacturing | 2017 |
| Supastitch Washington Ltd | Other services | 2018 |
| Super FRY South Shields Ltd | Hospitality | 2020 |
| Superior Gifts Limited | Wholesale & retail | 2011 |
| Superior Recruitment Group Limited | Administrative & support | 2018 |
| Support Health and Wellbeing Limited | Health & social care | 2020 |
| Sure Safe (North East) Limited | Education | 2012 |
| Sureplug Barber Shop Ltd | Other services | 2025 |
| Surface Solutions NE Limited | Extraterritorial | 2021 |
| Surfwheel Limited | Water & waste | 1991 |
| Survaze Limited | Professional & scientific | 2025 |
| Survey Concepts Ltd | Professional & scientific | 2018 |
| Surveying H.J. Ltd | Professional & scientific | 2024 |
| Surveywise Ltd | Professional & scientific | 2016 |
| Susan Veitch Consulting Ltd | Information & communication | 2021 |
| Suzie’S DEN Limited | Hospitality | 2024 |
| SV Bhadrakali Ltd | Hospitality | 2026 |
| Swaad Catering Ltd | Hospitality | 2025 |
| Swav Hair Sunderland Ltd | Other services | 2026 |
| Sweeney Miller LLP | | 2012 |
| Sweet Sensations (NE) Ltd | Hospitality | 2016 |
| Sweet Smash Ltd | Hospitality | 2026 |
| Sweetsfactory Limited | Manufacturing | 2024 |
| SWF (Sunderland) Limited | Construction | 2019 |
| Swift 1012 Limited | Professional & scientific | 1951 |
| Swift and Bold Ltd | Professional & scientific | 2020 |
| Swiftmovers & Logistics Ltd | Transport & logistics | 2026 |
| Swim City Family Ltd | Education | 2025 |
| Swim City Harton LLP | | 2026 |
| Swim City LLP | | 2018 |
| Swim City Shop Ltd | Wholesale & retail | 2025 |
| Swimcity Birtley LLP | | 2024 |
| Swinney & Crabtree Ltd | Construction | 2003 |
| Swinney Skip Hire Ltd | Water & waste | 2021 |
| Swwind Limited | Manufacturing | 2019 |
| Swyft Consulting Limited | Construction | 2024 |
| SX Global United Ltd | Arts & recreation | 2024 |
| SX Group Holding UK Ltd | Arts & recreation | 2025 |
| SYA Properties Ltd | Real estate | 2022 |
| Sybil Productions Ltd | Information & communication | 2023 |
| Syedz Properties Ltd | Real estate | 2025 |