| Springvale Foods Ltd | Wholesale & retail | 2014 |
| Sprinkles and Swirls Limited | Manufacturing | 2026 |
| Spriteshall Lane & Eastland Court Residents Association Limited | Households | 2020 |
| Sproughton Community Shop Community Interest Company | Wholesale & retail | 2009 |
| Sproughton Court Maintenance Company Limited | Households | 1977 |
| Sproughton Garden Machinery Ltd | Other services | 2024 |
| Sproughton Millennium Green Limited | Arts & recreation | 2011 |
| Sproughton Storage 1 Ltd | Administrative & support | 2025 |
| Sproughton Storage Ltd | Administrative & support | 2024 |
| SPS Technology Recruitment Limited | Information & communication | 2023 |
| Spurgeon Interiors Limited | Construction | 2016 |
| Spyral Software Ltd | Information & communication | 2024 |
| Square PEG Round Hole GML Ltd | Arts & recreation | 2025 |
| Squash & Stretch Animation Limited | Administrative & support | 2009 |
| Squeezle Ltd | Information & communication | 2012 |
| Squirrel Productions Limited | Information & communication | 2014 |
| Squirrell's Coaches Limited | Transport & logistics | 2003 |
| SR Medacs Limited | Health & social care | 2018 |
| Src-Hmo Ltd | Real estate | 2018 |
| Srdofresh Fish Limited | Hospitality | 2026 |
| SRI Industries Ltd | Manufacturing | 2024 |
| Srima Tech Limited | Information & communication | 2025 |
| SRM Groceries Ltd | Wholesale & retail | 2019 |
| SRP IT Support Ltd | Information & communication | 2024 |
| SS Legal Consulting Ltd | Professional & scientific | 2018 |
| SS Online Retail Ltd | Administrative & support | 2023 |
| Ssav Medigroww Limited | Professional & scientific | 2024 |
| SSD Associates Ltd | Transport & logistics | 2023 |
| Ssja Consultancy Ltd | Information & communication | 2019 |
| SSL Ventures Limited | Professional & scientific | 2025 |
| Ssmc Alumni UK Ltd | Other services | 2025 |
| Sssr Limited | Health & social care | 2019 |
| ST Accountancy Services Ltd | Professional & scientific | 2019 |
| ST Clements Golf Club Limited | Arts & recreation | 2013 |
| ST Cooker Services Ltd | Manufacturing | 1997 |
| ST David Healthcare Ltd | Health & social care | 2020 |
| ST Edmunds Gate (Bury ST Edmunds) Management Company Limited | Households | 2024 |
| ST Edmundsbury and Ipswich Academies Umbrella Trust | Education | 2013 |
| ST Edmundsbury and Ipswich Diocesan Multi-Academy Trust | Education | 2015 |
| ST Edmundsbury Chamber of Commerce and Industry Limited | Other services | 1995 |
| ST Elizabeth Care Agency Ltd | Health & social care | 2013 |
| ST Freight Solutions Ltd | Transport & logistics | 2026 |
| ST Future Ltd | Financial services | 2025 |
| ST George's Works Limited | Construction | 2015 |
| ST Georges Park (Needham Market) Management Company Limited | Households | 2018 |
| ST Helens Autism Support and Care Ltd | Health & social care | 2023 |
| ST Joseph's College Limited | Education | 1995 |
| ST Lukes Court (Ipswich) Management Company Limited | Real estate | 2007 |
| ST Mary's (Ipswich) Management Company Limited | Real estate | 2002 |
| ST Peter’S Place (Stutton) Management Company Limited | Households | 2020 |
| ST. Peter's by the Waterfront Limited | Administrative & support | 2007 |
| St.A+ Services Ltd | Construction | 2025 |
| St.Edmundsbury and Ipswich Diocesan Board of Finance | Other services | 1916 |
| ST4R Properties Ltd | Real estate | 2017 |
| Stace Provision Limited | Education | 2026 |
| Stacey Marie Estates Ltd | Real estate | 2025 |
| Stacey Marie Holdings Limited | Professional & scientific | 2024 |
| Stacey Marie Homes Ltd | Construction | 2023 |
| Stackyard Green Management Company Limited | Real estate | 2020 |
| Staffordshire Projects Ltd | Construction | 2024 |
| Stage Event Security Ltd | Administrative & support | 2013 |
| Stage Right Entertainments Ltd | Administrative & support | 2024 |
| Staines Real Estate Ltd | Real estate | 2023 |
| Stainless Cleaning Ltd | Wholesale & retail | 2025 |
| Stamford Appointments Limited | Extraterritorial | 2006 |
| Stamford Consumer Search Limited | Extraterritorial | 2007 |
| Stamford TMT Limited | Extraterritorial | 2008 |
| Stamina Holdings Ltd | Arts & recreation | 2020 |
| Standab UK Limited | Energy | 2025 |
| Standard Organics International (UK) Ltd | Wholesale & retail | 2006 |
| Standing Tall Group Ltd | Administrative & support | 2019 |
| Stanley & Buddy Enterprises Ltd | Hospitality | 2019 |
| Stansfields Transport Solutions Ltd | Transport & logistics | 2022 |
| Stanstead Ltd | Construction | 2020 |
| Stantech Development Group Limited | Construction | 2017 |
| Stanway Travel Ltd. | Real estate | 2001 |
| Stanwell Boston Limited | Wholesale & retail | 1986 |
| Star 76 Ltd | Transport & logistics | 2018 |
| Star Alteration Ltd | Other services | 2019 |
| Star Barber Ipswich Ltd | Other services | 2025 |
| Star Bright Catering Limited | Hospitality | 2021 |
| Star Editions Limited | Manufacturing | 2008 |
| Star Light Connect Limited | Transport & logistics | 2026 |
| Star Light Production Services Ltd | Professional & scientific | 2016 |
| STAR99 Limited | Administrative & support | 2024 |
| Starboard Bidco Limited | Financial services | 2024 |
| Starboard Finco Limited | Financial services | 2024 |
| Starboard Midco Limited | Financial services | 2024 |
| Starboard Topco Limited | Financial services | 2024 |
| Starco Invest Limited | Financial services | 2021 |
| Starcor Limited | Real estate | 2023 |
| Stardust Hadleigh Limited | Education | 2020 |
| Stardust Rentals Limited | Real estate | 2024 |
| Stargill Ltd | Real estate | 2025 |
| Stark Trading Limited | Wholesale & retail | 2024 |
| Starline Group Ltd | Real estate | 2021 |
| Starline Holidays & Travel Ltd | Administrative & support | 2022 |
| Starling Blue Ltd | Administrative & support | 2022 |
| Starling Equine Vets Ltd | Professional & scientific | 2024 |
| Starling Global Ltd | Construction | 2009 |