| Stoney Court Management Limited | Households | 2019 |
| Stoney CT Limited | Households | 2022 |
| Stoney Enterprises Ltd | Wholesale & retail | 2023 |
| Stoney Mews (Winchester) Limited | Households | 2013 |
| Stories That Mean Business Limited | Information & communication | 2012 |
| Stormflame Limited | Administrative & support | 2001 |
| Story Social Ltd | Arts & recreation | 2022 |
| Storyboard Architects Ltd | Professional & scientific | 2016 |
| Stotfold Road Profits Ltd | Real estate | 2025 |
| Strait-Bd Ltd | Education | 2016 |
| Strata Design Associates Ltd | Professional & scientific | 2017 |
| Stratagem Worldwide Limited | Other services | 2015 |
| Strategen International Limited | Professional & scientific | 2001 |
| Strategic HR Transformations Ltd | Information & communication | 2022 |
| Strategic Technology Engineering and Manufacturing Limited | Administrative & support | 2023 |
| Stratnode Ltd | Professional & scientific | 2026 |
| Stratton Hill Limited | Administrative & support | 2021 |
| Stratton House (Winchester) Management Ltd | Households | 2019 |
| Stratton Technical Distribution Ltd | Financial services | 2025 |
| Stratus Accounting Limited | Professional & scientific | 2013 |
| Strawhouse Limited | Real estate | 2012 |
| Strenia Ltd | Professional & scientific | 2025 |
| Stretch Resources Ltd | Professional & scientific | 2022 |
| Stretch Trading Limited | Information & communication | 2023 |
| Stride Management Limited | Real estate | 2024 |
| Strive EP Limited | Wholesale & retail | 2022 |
| Strollon Limited | Extraterritorial | 2012 |
| Stroud Park Limited | Real estate | 2013 |
| Structured Software Design Consultants Limited | Information & communication | 1997 |
| Stuart Peach Consultancy Ltd | Professional & scientific | 2021 |
| Student Natives Limited | Real estate | 2018 |
| Studio O Architects Limited | Professional & scientific | 2015 |
| Studio Scott Design Ltd | Professional & scientific | 2025 |
| Studio Squeeze Ltd | Professional & scientific | 2021 |
| Studio Stellen Limited | Professional & scientific | 2025 |
| Studytech AI Ltd | Information & communication | 2026 |
| Stuga Ltd | Manufacturing | 2026 |
| SUE Mann Consultancy Limited | Administrative & support | 2010 |
| Sugar Healthcare Limited | Health & social care | 2015 |
| Sugar Supplies & Services International Ltd | Professional & scientific | 2014 |
| Sugar Vista Ltd | Professional & scientific | 2017 |
| Sulismart Ltd | Wholesale & retail | 2025 |
| Sullivan Harvey (2025) Limited | Construction | 2025 |
| Summersdale Court Management Company Limited | Households | 1976 |
| Summertree Architects Limited | Professional & scientific | 2018 |
| Summerway Consulting Limited | Professional & scientific | 2013 |
| Summit Estates Limited | Construction | 1958 |
| Summit Wellness Group Ltd | Arts & recreation | 2024 |
| Sumotronics Limited | Wholesale & retail | 2019 |
| Sunbean Roasters Ltd | Manufacturing | 2025 |
| Sunlight Assessments UK Limited | Professional & scientific | 2023 |
| Sunnyside Art Studio Ltd | Arts & recreation | 2020 |
| Sunstone Design Limited | Professional & scientific | 2009 |
| Suntrail Limited | Transport & logistics | 2025 |
| Supercar Scene Limited | Information & communication | 2012 |
| Superfuntastic Ltd | Wholesale & retail | 2023 |
| Superyacht Crew UK Ltd | Administrative & support | 2022 |
| Superyacht Interiors (UK) Ltd | Construction | 2026 |
| Superyacht Services Limited | Transport & logistics | 2015 |
| Support Ashore Limited | Transport & logistics | 2008 |
| Supremacy Park Home Renovations Limited | Construction | 2016 |
| Supreme Cabs Winchester Ltd | Transport & logistics | 2024 |
| Surespa Ltd | Wholesale & retail | 2014 |
| Surrey Investors Club Limited | Financial services | 2016 |
| Survilience International Limited | Information & communication | 2016 |
| Susie Atkinson Design Limited | Professional & scientific | 2013 |
| Suspect Packages Ltd | Wholesale & retail | 2003 |
| Sussex Close (Hursley) Management Company Limited | Extraterritorial | 2012 |
| Sustainable Enterprise Centre Ltd | Professional & scientific | 2022 |
| Sustainable Enterprise Partnership LLP | | 2022 |
| Sustainic Limited | Professional & scientific | 2025 |
| Sustenance Limited | Professional & scientific | 2009 |
| Sutch Consulting International Limited | Professional & scientific | 2006 |
| Svnd Ltd | Manufacturing | 2022 |
| SW Shoot Ltd | Arts & recreation | 2013 |
| Swallow Field (Sutton Scotney) Management Company Limited | Real estate | 1998 |
| Swarve Limited | Information & communication | 2012 |
| Sweet Italian Pizza Ltd | Hospitality | 2023 |
| Sweet Resource Ltd | Administrative & support | 2023 |
| Swift Golf Limited | Manufacturing | 2026 |
| Swim Racing Ltd | Information & communication | 2017 |
| Swimming Dogs Limited | Information & communication | 2022 |
| Swirly Peak Ltd | Professional & scientific | 2024 |
| Switch Accounting Limited | Professional & scientific | 2010 |
| Switchblade International Limited | Wholesale & retail | 2009 |
| Switchblade UK Limited | Wholesale & retail | 2018 |
| Swithuns View Limited | Hospitality | 1999 |
| Swtchup Ltd | Information & communication | 2026 |
| Sycamore Hill Ltd | Information & communication | 2022 |
| Sycamore House (Twyford) Management Company Limited | Extraterritorial | 2006 |
| Sydney's Services Ltd | Other services | 2023 |
| Syed Rosul Properties Limited | Real estate | 2023 |
| Sykes Construction and Development Services Ltd | Construction | 2018 |
| Sylvatica Consulting Services Ltd | Professional & scientific | 2025 |
| Symatrix Limited | Information & communication | 2000 |
| Symes Industrial Ltd | Manufacturing | 1999 |
| Symmetry Land Profits Ltd | Real estate | 2024 |
| Sympli Ltd | Other services | 2023 |
| Syna Development Limited | Real estate | 1986 |
| Synergy PMC Limited | Professional & scientific | 2002 |