| Stoney & Co Construction Limited | Construction | 2010 |
| Stonham Bar Ltd | Hospitality | 2024 |
| Stonham Barns Golf Centre Limited | Arts & recreation | 1996 |
| Stonham Garden Centre Ltd | Wholesale & retail | 2023 |
| Store Energy Ltd | Professional & scientific | 2020 |
| Stour Valley Beagles Limited | Agriculture & fishing | 2008 |
| Stow Glow Ltd | Other services | 2025 |
| Stow Grill Ltd | Hospitality | 2024 |
| Stow Heating Services Limited | Construction | 2013 |
| Stow Ladies Fitness Limited | Arts & recreation | 2016 |
| Stow Pizza Ltd | Hospitality | 2026 |
| Stow Property Investments Limited | Real estate | 2021 |
| Stowafric Hair Limited | Other services | 2025 |
| Stowcare Holdings Limited | Health & social care | 2006 |
| Stowcare Limited | Health & social care | 1992 |
| Stowe Warehousing Limited | Transport & logistics | 1993 |
| Stowhealth Holdings Limited | Professional & scientific | 2020 |
| Stowmarket Aggregates Ltd | Wholesale & retail | 2010 |
| Stowmarket Barber Ltd | Other services | 2025 |
| Stowmarket Community Sports & Social Club Community Interest Company | Arts & recreation | 2009 |
| Stowmarket Exhaust & Tyre Centre Limited | Wholesale & retail | 1984 |
| Stowmarket EYE Care Limited | Wholesale & retail | 2014 |
| Stowmarket Golf Centre Limited | Arts & recreation | 2003 |
| Stowmarket Jewellery, Antiques & Collectables Ltd | Wholesale & retail | 2026 |
| Stowmarket Landscapes Limited | Administrative & support | 2024 |
| Stowmarket Meadlands Recreation Club | Arts & recreation | 2008 |
| Stowmarket Mortgage Centre Limited | Financial services | 2014 |
| Stowmarket Museum Trading Company Limited | Wholesale & retail | 1993 |
| Stowmarket Razor Ltd | Other services | 2025 |
| Stowmarket Skips Ltd | Water & waste | 2020 |
| Stowmarket Store Ltd | Wholesale & retail | 2018 |
| Stowmet Limited | Hospitality | 2025 |
| Stowtax Limited | Professional & scientific | 2022 |
| Stowupland Foods Ltd | Hospitality | 2022 |
| Stowupland Preschool & the Mighty Oaks | Education | 2008 |
| Strada Innovation Limited | Professional & scientific | 2003 |
| Stringer & Kennington Ltd | Construction | 2023 |
| Structure Scaffolding (Suffolk) Ltd | Construction | 2023 |
| Strutton Lime Plastering Ltd | Administrative & support | 2018 |
| Stryding Limited | Information & communication | 2026 |
| Stuart Mack Services Limited | Professional & scientific | 2020 |
| Studio 19 Hair Design Ltd | Other services | 2013 |
| Studio 90 Limited | Professional & scientific | 2016 |
| Studio Polka Limited | Professional & scientific | 2021 |
| Studley Capital Limited | Real estate | 2019 |
| Styles Tool and Plant Hire Ltd | Administrative & support | 2025 |
| Suffolk Bridal Outlet Limited | Wholesale & retail | 2019 |
| Suffolk Build Limited | Construction | 2009 |
| Suffolk Car and Van Ltd | Wholesale & retail | 2026 |
| Suffolk Country Lodges Ltd | Real estate | 2025 |
| Suffolk Country Services Ltd | Agriculture & fishing | 2016 |
| Suffolk County FA Trading Limited | Arts & recreation | 2024 |
| Suffolk County Football Association Limited | Arts & recreation | 1999 |
| Suffolk Crown Ltd | Wholesale & retail | 2025 |
| Suffolk Dwelling Limited | Real estate | 2022 |
| Suffolk Endocrinology UK Limited | Health & social care | 2019 |
| Suffolk Fire and Security Ltd | Construction | 2024 |
| Suffolk Floor Sanding Limited | Construction | 2022 |
| Suffolk Garage Doors Ltd | Construction | 2024 |
| Suffolk Garden Works Limited | Administrative & support | 2019 |
| Suffolk Golf Academy Ltd | Education | 2025 |
| Suffolk Groundworks & Construction Ltd | Construction | 2021 |
| Suffolk Hardwoods Limited | Extraterritorial | 2024 |
| Suffolk Landscape Construction (UK) Limited | Administrative & support | 2022 |
| Suffolk Landscapes and Construction Ltd | Construction | 2025 |
| Suffolk Landscaping & Maintenance Limited | Administrative & support | 2025 |
| Suffolk Landscaping & Masonry Limited | Administrative & support | 2018 |
| Suffolk Lawn & Landscaping Ltd | Administrative & support | 2025 |
| Suffolk Macs Limited | Information & communication | 2003 |
| Suffolk Mobility Events Ltd | Arts & recreation | 2024 |
| Suffolk Mobility Limited | Extraterritorial | 2006 |
| Suffolk Mobility Solutions Limited | Construction | 2020 |
| Suffolk Motor Group Ltd | Wholesale & retail | 2026 |
| Suffolk Packaging Limited | Wholesale & retail | 2026 |
| Suffolk Primary Care Limited | Health & social care | 2025 |
| Suffolk Roof Cleaning Limited | Administrative & support | 2024 |
| Suffolk Soaring Group Ltd | Arts & recreation | 2020 |
| Suffolk Solar & Electrical Ltd | Construction | 2024 |
| Suffolk Supplies Ltd | Wholesale & retail | 2019 |
| Suffolk Tax Returns Limited | Professional & scientific | 1999 |
| Suffolk Timber Fencing Limited | Extraterritorial | 2020 |
| Suffolk Timber Gates Limited | Extraterritorial | 2020 |
| Suffolk Timber Group Limited | Extraterritorial | 2020 |
| Suffolk Timber Products Limited | Manufacturing | 2016 |
| Suffolk Timber Supplies Limited | Extraterritorial | 2020 |
| Suffolk Vista Ltd | Real estate | 2025 |
| Suffolks Motor Group Ltd | Wholesale & retail | 2026 |
| Suituk Limited | Manufacturing | 2014 |
| Sun Environmental Services Ltd | Financial services | 2020 |
| Sun Skips Ltd | Extraterritorial | 2021 |
| Suncrest Rise (Creeting) Management Company Ltd | Households | 2009 |
| Super Assist Solutions Ltd | Professional & scientific | 2021 |
| Super Shine Car Valeting Ltd | Other services | 2021 |
| Superb Airport Transfers Limited | Transport & logistics | 2014 |
| Supercharged Performance Ltd | Wholesale & retail | 2016 |
| Superhero Fitness Ltd. | Arts & recreation | 2015 |
| Superior Driveways Limited | Construction | 2019 |
| Supersips Limited | Manufacturing | 2011 |
| Supersips LOW Carbon Panels Limited | Extraterritorial | 2015 |
| Supersips Transport Limited | Transport & logistics | 2020 |