| Srnfabrication Ltd | Manufacturing | 2017 |
| Sroka Ltd | Transport & logistics | 2011 |
| Srssl 06630307 Limited | Administrative & support | 2008 |
| Sruvik Solutions Limited | Information & communication | 2017 |
| SS & AA Limited | Wholesale & retail | 2015 |
| SS Dhillon Ltd | Construction | 2017 |
| SS International Ltd | Wholesale & retail | 2019 |
| SS Petroleum Limited | Wholesale & retail | 2018 |
| SS Prime Estates Ltd | Real estate | 2025 |
| SSB Wholesale Ltd | Wholesale & retail | 2024 |
| SSC Industrial Flooring Ltd | Construction | 2014 |
| SSG Care Services Ltd | Health & social care | 2022 |
| SSG Property Investments Ltd | Real estate | 2022 |
| Ssgda Limited | Hospitality | 2022 |
| SSH Transit Ltd | Transport & logistics | 2026 |
| SSJ Consulting Solutions Ltd | Professional & scientific | 2016 |
| SSL Design & Fabrication Limited | Manufacturing | 2005 |
| SSL Electrical Ltd | Construction | 2012 |
| Sssc Consulting Limited | Information & communication | 2026 |
| ST Antonio School of Music Ltd | Information & communication | 2024 |
| ST Blaize Court RTM Company Limited | Households | 2018 |
| ST Catherine's Catholic Primary School (Academy) Swindon | Education | 2012 |
| ST Catherine's Court (Wroughton) Management Company Limited | Households | 2005 |
| ST Consultancy Services Ltd | Professional & scientific | 2021 |
| ST Contracting Limited | Construction | 2010 |
| ST Edward's Press Ltd | Information & communication | 2000 |
| ST Georges Works Management Company Limited | Households | 2019 |
| ST Johns Court RTM Company Limited | Households | 2011 |
| ST Johns Fish and Chip Shop Limited | Hospitality | 2013 |
| ST Joseph's Catholic College | Education | 2011 |
| ST Joseph's Professional Services Ltd | Education | 2016 |
| ST Margarets Chase (Stratton ST Margaret) Management Company Limited | Households | 2002 |
| ST Mary's (Purton) Residents Management Company | Households | 2018 |
| ST Mary's Catholic Primary School (Academy Trust), Swindon | Education | 2011 |
| ST Michaels Close Lambourn Limited | Real estate | 2020 |
| ST Paul's Court (Swindon) Management Company Limited | Households | 2017 |
| ST Peter's Place (Swindon) Management Company Limited | Households | 2007 |
| ST Peters Cottages (Broad Hinton) Management Company Limited | Households | 1994 |
| ST Premier Limited | Transport & logistics | 2025 |
| ST Schrader Holding Company UK Limited | Financial services | 2014 |
| Stablecourt (Wootton Bassett) Management Company Limited | Households | 1983 |
| STACK300 Ltd | Information & communication | 2025 |
| Stackful Ltd | Information & communication | 2024 |
| Staffordshire Campus Living LLP | | 2023 |
| Stag Buying Group Limited | Wholesale & retail | 1991 |
| Stage Academy London LLP | | 2022 |
| Stage Gate Project Services Ltd | Other services | 2024 |
| Stagg Holdings Limited | Financial services | 2017 |
| Stainless Steel Fittings (UK) Ltd | Wholesale & retail | 2016 |
| Stainswick Farm OIL LLP | | 2010 |
| Stajuma Care Ltd | Health & social care | 2025 |
| Stake 3 Limited | Wholesale & retail | 2014 |
| Stalloni Campioni Racing Ltd | Education | 2026 |
| Stanbury Analytics Ltd | Professional & scientific | 2022 |
| Stans Vans Swindon Limited | Transport & logistics | 2025 |
| Stanton Court Management Services Limited | Real estate | 2004 |
| Stanton Management Ltd | Administrative & support | 2013 |
| Stanton Prop Co Limited | Real estate | 2025 |
| Staples FM Ltd | Administrative & support | 2025 |
| Star Baner Tech Ltd | Manufacturing | 2025 |
| Star Beautician Ltd | Other services | 2019 |
| Star Dreamer Ltd | Arts & recreation | 2025 |
| Star Groundwork's & Construction Ltd | Construction | 2017 |
| Star Taxis(Swindon) Ltd | Administrative & support | 2022 |
| Star Turkish Barber Ltd | Other services | 2018 |
| Star Turkish UK Barbers Ltd | Other services | 2025 |
| Star West Management Company Limited | Real estate | 2005 |
| Star World Convenience Ltd | Wholesale & retail | 2021 |
| Star World Convinience Limited | Wholesale & retail | 2025 |
| Starlet Dance School LLP | | 2017 |
| Starlight Path Ltd | Health & social care | 2025 |
| Starline Digital Solutions Ltd | Information & communication | 2026 |
| Starmore Property Ltd | Real estate | 2021 |
| Starpro Management Solutions Limited | Professional & scientific | 2010 |
| Stars Trans Ltd | Transport & logistics | 2026 |
| Start Right Construction Limited | Construction | 2022 |
| Statement Drives & Patios Limited | Construction | 2025 |
| Statement Home Improvements Ltd | Construction | 2018 |
| Static Airwaves Limited | Information & communication | 2012 |
| Station Approach (Swindon) Management Company Limited | Households | 2014 |
| Station Barber Chatham Ltd | Other services | 2025 |
| Station Shop Swindon Limited | Wholesale & retail | 2025 |
| Station Walk Station Road Swindon Management Company Limited | Households | 2003 |
| Status One Ltd | Other services | 1979 |
| Staunch Security Ltd | Administrative & support | 2014 |
| Stava Accountancy Limited | Professional & scientific | 2015 |
| Stay Lean Limited | Wholesale & retail | 2017 |
| Staybrook Asset Management Limited | Real estate | 2024 |
| Staybrook Capital Limited | Real estate | 2024 |
| Staybrook Properties LLP | | 2025 |
| Stays by JO Ltd | Hospitality | 2018 |
| Stays Online Ltd | Information & communication | 2024 |
| STC Forest School Ltd | Education | 2023 |
| STC Tuition Ltd | Education | 2022 |
| Steam (Museum of the Great Western Railway) Limited | Arts & recreation | 1998 |
| Steam Queens Limited | Households | 2006 |
| Steel Apex Ltd | Arts & recreation | 2023 |
| Steel Enterprises Limited | Administrative & support | 2019 |
| Steel Group Holdings Limited | Financial services | 2021 |
| Steel Vintage Limited | Wholesale & retail | 2011 |