| Sherbourne Mattingley Ltd | Construction | 2020 |
| Sherbourne Sennington Ltd | Construction | 2023 |
| Sherbourne ST Peter's Ltd | Construction | 2019 |
| Sherbourne Tailormade Ltd | Construction | 2021 |
| Sherbourne Wexcombe Ltd | Construction | 2022 |
| Shipton Limited | Mining & quarrying | 2011 |
| Shire Ventilation Limited | Construction | 2013 |
| Shopfit 24 Limited | Construction | 2022 |
| Signature Floors Ltd | Other services | 2010 |
| Silbury Shooting Limited | Agriculture & fishing | 2019 |
| Silhouette House Ltd | Professional & scientific | 2018 |
| Silver Office Recruitment Limited | Administrative & support | 2019 |
| Silver Screen Postproduction Limited | Information & communication | 1973 |
| Silverback Consulting Limited | Professional & scientific | 2024 |
| Silverless Limited | Professional & scientific | 2013 |
| Silverton Investments Limited | Wholesale & retail | 1997 |
| Simon Johnson Architects Ltd | Administrative & support | 2013 |
| Sing Space CIC | Arts & recreation | 2025 |
| SJ Stephens Associates Limited | Administrative & support | 2004 |
| SJS Land Capital Ltd | Real estate | 2025 |
| SKS Brickwork Limited | Construction | 2016 |
| Skylark Aeronautical Limited | Manufacturing | 2025 |
| Skyley Photonics Limited | Professional & scientific | 2024 |
| Slca Limited | Real estate | 2013 |
| Slmg Consulting Ltd | Information & communication | 2006 |
| Smart Thinking Consultancy Limited | Professional & scientific | 2012 |
| Smartmaven Limited | Information & communication | 2021 |
| Smartwater Testing Limited | Water & waste | 2016 |
| Smith Data Science Ltd | Information & communication | 2021 |
| Smitten Property Ltd | Real estate | 2025 |
| Soft Options Water Softeners Limited | Wholesale & retail | 2012 |
| Solent Investments Holdings Limited | Financial services | 2021 |
| Solent Investments Limited | Construction | 1959 |
| Solid State (Easton) Ltd | Real estate | 2017 |
| Sollis Property Finance Consultants Limited | Financial services | 2009 |
| Solutions Swim School LLP | | 2022 |
| Sommelier Fine Wine Limited | Wholesale & retail | 2009 |
| Sonakora Ltd | Information & communication | 2026 |
| South West Foot Surgery Ltd | Health & social care | 2018 |
| Southern Counties Leisure Ltd | Arts & recreation | 2020 |
| Southill Events Ltd | Arts & recreation | 2021 |
| Sovereign Test Ltd | Professional & scientific | 2026 |
| Sovereign Titan Storage Ltd | Transport & logistics | 2026 |
| Space Overflow Storage Limited | Wholesale & retail | 2016 |
| SPARE1 Ltd | Real estate | 2019 |
| Spatial Silicon Limited | Information & communication | 2023 |
| SPC Construction (Swindon) Limited | Construction | 2023 |
| Spica Consultants Limited | Professional & scientific | 1993 |
| Sporting Tactics Limited | Administrative & support | 1989 |
| ST James CZ Limited | Financial services | 2014 |
| ST James Nominees Limited | Financial services | 2013 |
| ST. Mary's Field (Management) Company Limited | Real estate | 1996 |
| ST. Peter's & ST. Paul's Marlborough Trust Limited | Education | 1978 |
| Stadium Artists Ltd | Arts & recreation | 2013 |
| Stairway to Nowhere Ltd | Administrative & support | 2026 |
| Standard Triumph Motor Company Ltd | Wholesale & retail | 2023 |
| Standing Tall Consulting Limited | Other services | 2026 |
| Stanley Moffat Limited | Construction | 2010 |
| Stanley's Day Care Limited | Other services | 2021 |
| Stanton Catering LLP | | 2020 |
| Starcus Ltd | Information & communication | 2023 |
| Starveall Ltd | Arts & recreation | 2017 |
| Stellaris Trade Limited | Wholesale & retail | 2026 |
| Stevson Developments Ltd | Real estate | 2020 |
| Stewart-Fosh Consulting Ltd | Professional & scientific | 2025 |
| Stockdale and Wilson Ltd | Real estate | 2022 |
| Stoic Clothing Limited | Extraterritorial | 2025 |
| Stokesay Limited | Information & communication | 2018 |
| Stokke Consulting Limited | Professional & scientific | 2024 |
| Stone & Silver Limited | Wholesale & retail | 2012 |
| Stoneking Management Limited | Households | 2001 |
| Stonevole Ltd | Information & communication | 2026 |
| Stor Limited | Transport & logistics | 2001 |
| Stowell Farms Limited | Agriculture & fishing | 2022 |
| Stream Hygiene Limited | Wholesale & retail | 2010 |
| STRETCH-2-FIT Ltd | Arts & recreation | 2012 |
| Strictly Organised Solutions Ltd | Other services | 2010 |
| Striped Horse Construction Ltd | Construction | 2020 |
| Strong Decorating Ltd | Extraterritorial | 2012 |
| Strongmanrequired.Com Ltd | Information & communication | 2026 |
| STS Invest Limited | Households | 2011 |
| Stuart Hall Cycling Limited | Administrative & support | 2018 |
| Studio Ginkgo Ltd | Real estate | 2025 |
| SUB Retro Ltd | Wholesale & retail | 2018 |
| Suddene Park Ltd | Agriculture & fishing | 2016 |
| SUE Brady Catering Limited | Hospitality | 2004 |
| Suffolk Associates Limited | Construction | 2006 |
| Sugarway Limited | Information & communication | 2002 |
| Sugden & Sugden Ltd | Households | 2023 |
| Summerdown and Partners Limited | Real estate | 1994 |
| Summit Integrated Facilities Ltd | Administrative & support | 2026 |
| Sunflowers at Grafton | Education | 2012 |
| Sunnyhill Dairy Limited | Agriculture & fishing | 2013 |
| Superconscious Child Productions Ltd | Information & communication | 2024 |
| Susie Watson Designs Ltd | Wholesale & retail | 1999 |
| Swann Solutions Ltd | Administrative & support | 2024 |
| Swindon Electrical Contractors Limited | Construction | 2018 |
| Sxybtch Wines Limited | Wholesale & retail | 2026 |
| Sycamore Seed Limited | Information & communication | 2018 |
| Symmetricity Limited | Information & communication | 2010 |