| Software Universe Limited | Information & communication | 1997 |
| Solar Beach Limited | Professional & scientific | 2025 |
| Solar Experts Energy Solutions Ltd | Administrative & support | 2018 |
| Something Else to EAT Limited | Hospitality | 2014 |
| Sonning Developments Limited | Real estate | 1996 |
| Sophia Breath Ltd | Other services | 2024 |
| Sophus Limited | Professional & scientific | 2001 |
| Soulful Equity Holdings Ltd | Real estate | 2024 |
| Sound Solutions London Ltd | Construction | 2016 |
| Sound Stop Solutions Residential Limited | Construction | 2013 |
| South East Property Lets Limited | Real estate | 2003 |
| Southern Spares and Shells Ltd | Wholesale & retail | 2024 |
| Southgate Advisors Ltd | Financial services | 2025 |
| Sovereign Gate Residents Company Limited | Households | 2002 |
| Spaininvest Limited | Financial services | 2022 |
| Spare Crib Global Limited | Hospitality | 2024 |
| Spare Crib Limited | Hospitality | 2020 |
| Spark Emotions Limited | Professional & scientific | 2003 |
| SPE Engineering Services Ltd | Professional & scientific | 2022 |
| Specialist PR & Advisory Services Limited | Professional & scientific | 2023 |
| Spectrum Entertainment Services Ltd | Administrative & support | 2022 |
| Spiral Consultancy (Ascot) Limited | Construction | 2018 |
| Spoolup Consulting Limited | Professional & scientific | 2021 |
| Sporting Rifle Club Limited | Education | 2020 |
| Sports Physios Limited | Health & social care | 2001 |
| Spring Books Limited | Professional & scientific | 2025 |
| Spring Yoga Ltd | Arts & recreation | 2025 |
| Squawk Ltd | Information & communication | 2008 |
| SR Legal Consultancy Limited | Professional & scientific | 2016 |
| Sree Five Nine Limited | Administrative & support | 2011 |
| SS Law Consultancy Limited | Professional & scientific | 2025 |
| Sstnt Ltd | Real estate | 2025 |
| ST George's Ascot Enterprises Limited | Education | 2015 |
| ST James and Country Estates Limited | Extraterritorial | 2001 |
| ST. Bruno Flats Limited | Hospitality | 1995 |
| ST. Mary's Ascot Trading Company Limited | Education | 1991 |
| ST7 Consulting Ltd | Professional & scientific | 2022 |
| Staddon Floors Ltd | Construction | 2025 |
| Stadium Street Property Limited | Professional & scientific | 2015 |
| Stain-Shield Limited | Manufacturing | 1995 |
| Stakes Capital Limited | Professional & scientific | 2015 |
| Starlite International Trading Limited | Wholesale & retail | 1973 |
| State Mode Limited | Professional & scientific | 2022 |
| Stately Affair Exclusive Ltd | Professional & scientific | 2008 |
| Statlog Pro Limited | Information & communication | 2019 |
| Stay on Target Ltd | Arts & recreation | 2018 |
| Steadfast Autos Limited | Wholesale & retail | 2013 |
| Stepping Stones (Surrey) Ltd | Education | 2012 |
| Steps for Life Limited | Wholesale & retail | 2000 |
| Steps International Limited | Wholesale & retail | 1999 |
| Steven Mufti & Associates Limited | Financial services | 2013 |
| Sticks & Stones Driveway and Paving Ltd | Administrative & support | 2025 |
| Stockbourne (WEM) Ltd | Real estate | 2022 |
| Stockbourne Developments Limited | Real estate | 1989 |
| Stockbourne Group Limited | Real estate | 2001 |
| Stockbourne Limited | Real estate | 2002 |
| Stockbourne Management (Winkfield) Limited | Real estate | 2000 |
| Stockbourne Management Limited | Real estate | 1990 |
| Stoneguard Limited | Construction | 1966 |
| Stoneguard Technologies Limited | Water & waste | 2012 |
| STOREG8 Limited | Information & communication | 2024 |
| Storybook Asset Management Limited | Administrative & support | 2021 |
| Storybook Montessori Ascot Limited | Education | 2014 |
| Storybook Sunningdale Limited | Education | 2011 |
| Strata Supplies Shop Limited | Energy | 2022 |
| Stratamore Ltd | Professional & scientific | 2020 |
| Strategic Consultation Limited | Professional & scientific | 2024 |
| Strickland Green Limited | Professional & scientific | 2017 |
| Structural Design Associates Ltd | Professional & scientific | 2001 |
| Stuart Hill PGA Professional Limited | Wholesale & retail | 2002 |
| Student & Affordable Property Limited | Professional & scientific | 2013 |
| Studio Bamrah Ltd | Professional & scientific | 2020 |
| Studio Hanel Ltd | Manufacturing | 2014 |
| Styles (Sunningdale) Management Limited | Households | 1984 |
| Subhire Ltd | Administrative & support | 2020 |
| Subterranea Britannica | Other services | 2007 |
| SUM Skate Ltd | Wholesale & retail | 2021 |
| Sunning Property Maintenance Limited | Households | 2026 |
| Sunningdale MEP Design Ltd | Manufacturing | 2020 |
| Sunningdale Motors Limited | Wholesale & retail | 1978 |
| Sunningdale Solar & Battery Ltd. | Construction | 2022 |
| Sunninghill & Ascot Property Company Limited | Real estate | 2016 |
| Sunninghill & Ascot Property Services Limited | Real estate | 2017 |
| Sunninghill Carpets and Flooring Limited | Wholesale & retail | 1987 |
| Sunninghill Comrades Limited(The) | Real estate | 1920 |
| Sunninghill Cuisine Ltd | Hospitality | 2026 |
| Sunninghill Food Limited | Hospitality | 2017 |
| Sunninghill Play Centre Ltd | Education | 2010 |
| Sunninghill Restaurant Ltd | Hospitality | 2019 |
| Sunningpop Holding Limited | Real estate | 2025 |
| Sunningpop Limited | Hospitality | 2025 |
| Supermetal Consultancies Ltd | Professional & scientific | 2026 |
| Supervettura Sales Limited | Wholesale & retail | 2010 |
| Surebyte Limited | Information & communication | 1990 |
| Surestay Limited | Hospitality | 2025 |
| Surrey Basements Limited | Construction | 2008 |
| Surrey Clean Energy Ltd | Professional & scientific | 2020 |
| Surrey County Basements Limited | Extraterritorial | 2012 |
| Surrey Hi-Tech Design & Build Limited | Construction | 2021 |
| Surrey Hi-Tech Electrics Ltd | Construction | 2009 |