| Surreal Tech Limited | Information & communication | 2013 |
| Susan Ellis Limited | Professional & scientific | 2013 |
| Susanna Warren Consultancy Limited | Professional & scientific | 2022 |
| Susbde Finance Ltd | Administrative & support | 2021 |
| Sushi TEN Ltd | Hospitality | 2019 |
| Susrusha Limited | Health & social care | 2015 |
| Sussex Place Management Company Limited | Households | 1984 |
| Sustainable Environmental Services Ltd | Other services | 2026 |
| Sustainable Himalayan Ltd | Wholesale & retail | 2024 |
| Sustainable Solar Ltd | Energy | 2011 |
| Sustainconnect CIC | Public administration | 2017 |
| Sutherland IT Solutions Limited | Information & communication | 2025 |
| Sutton Old Station LLP | | 2013 |
| Suvana Cohousing Limited | Households | 2019 |
| Suwa Ltd | Other services | 2021 |
| Svasti Homes Ltd | Real estate | 2026 |
| Svictorykr Co., Ltd | Wholesale & retail | 2023 |
| Svkn Consultants Ltd | Professional & scientific | 2025 |
| Svnpt Piping Systems (UK) Ltd. | Extraterritorial | 2024 |
| Svram Limited | Professional & scientific | 2016 |
| SVS Creations Ltd | Professional & scientific | 2025 |
| SVS Partnership Limited | Professional & scientific | 2022 |
| SW Fish Ltd | Hospitality | 2026 |
| SW Gardens and Landscapes Ltd | Administrative & support | 2021 |
| SW15 Partners Limited | Real estate | 2009 |
| Swaddesh Limited | Hospitality | 2018 |
| Swaffham Prior Community Land Trust | Construction | 2013 |
| Swallow Gardens Property Management Company Limited | Real estate | 2014 |
| Swan Equities Limited | Administrative & support | 2008 |
| Swan Place (Cippenham) Management Limited | Households | 2014 |
| Swangap Flat Management Limited | Extraterritorial | 1991 |
| Swanholme Limited | Wholesale & retail | 2021 |
| Swanky Pads Limited | Real estate | 2004 |
| Swanscaped Ltd | Administrative & support | 2024 |
| Swarm Studio Ltd | Professional & scientific | 2015 |
| Swavesey Community Pavilion Limited | Arts & recreation | 2011 |
| Swavesey Festival Limited | Arts & recreation | 2007 |
| Swavesey Garage Ltd | Wholesale & retail | 2025 |
| Swavesey Windmill Ltd | Hospitality | 2024 |
| Sway Design Ltd | Wholesale & retail | 2019 |
| Sways Abode Limited | Real estate | 2024 |
| SWC Management Company Limited | Households | 1996 |
| Sweatdrop Studios Ltd. | Information & communication | 2009 |
| Swedish Orphan Biovitrum Ltd | Manufacturing | 2002 |
| Sweet Influence Consultancy (SIC) Ltd. | Professional & scientific | 2017 |
| Sweet Stay Limited | Real estate | 2022 |
| Sweetalicious Limited | Wholesale & retail | 2023 |
| Sweetie Factory Ltd. | Hospitality | 2022 |
| Sweetpea Market Garden CIC | Agriculture & fishing | 2026 |
| Sweettalk &Yordan Constructors Limited | Construction | 2019 |
| Sweven Design Ltd | Information & communication | 2014 |
| Swift Kitchen Ltd | Hospitality | 2015 |
| Swift Planning Ltd | Professional & scientific | 2023 |
| Swifts Close (DRY Drayton) Management Company Limited | Households | 2021 |
| Swim Boost for Kids Ltd | Education | 2017 |
| Swim Boost Ltd | Education | 2018 |
| Swinchatt DEV Ltd | Information & communication | 2022 |
| Swing Fitness Limited | Professional & scientific | 2021 |
| Swisstaps Ltd | Manufacturing | 2021 |
| Switch Vision Ltd | Information & communication | 2025 |
| SWK Park Housing Ltd | Real estate | 2025 |
| Sword Lowco Limited | Financial services | 2022 |
| Sword Midco Limited | Financial services | 2022 |
| Sword Topco Limited | Financial services | 2022 |
| SWT Estate Management Ltd | Households | 2023 |
| SWT Estates Consultancy Ltd | Professional & scientific | 2025 |
| SY Aviation Ltd | Manufacturing | 2025 |
| Syai UK Ltd | Extraterritorial | 2023 |
| SYB Home Partners Ltd | Construction | 2025 |
| Sycamore House HR Solutions Limited | Administrative & support | 2003 |
| Sycamore Properties (Cambs) Ltd | Real estate | 2022 |
| Sycamore View Management Company Limited | Real estate | 2020 |
| SYI Marine Service Co., Ltd | Extraterritorial | 2023 |
| Sylhut Ltd | Hospitality | 2023 |
| Syllatutors Limited | Education | 2023 |
| Sylva Vale Ltd | Agriculture & fishing | 2025 |
| Sylvan Hill Management Company Limited | Real estate | 2017 |
| Sylvia Newman Garden Design Limited | Administrative & support | 1995 |
| SYM Events Limited | Hospitality | 2022 |
| Symbiotic Tax Consulting Ltd | Professional & scientific | 2012 |
| Symmetry Lead Work Limited | Construction | 2017 |
| Symorphic Medical Technologies Ltd | Wholesale & retail | 2026 |
| Symphorna Limited | Professional & scientific | 2025 |
| Symptiq Ltd | Information & communication | 2026 |
| SYN3RGY Aviation Services Ltd | Manufacturing | 2025 |
| Synapcon UK Ltd | Information & communication | 2026 |
| Synapsework Ltd | Information & communication | 2012 |
| Synapture Limited | Information & communication | 2015 |
| Sync Inspire CIC | Professional & scientific | 2019 |
| Synchronicity Capital Limited | Professional & scientific | 2011 |
| Syndex BIO Ltd | Professional & scientific | 2022 |
| Syndicate Room BBI Nominees Ltd | Professional & scientific | 2020 |
| Syndicate Room Group Ltd | Financial services | 2016 |
| Syndicate Room Ltd | Financial services | 2011 |
| Syndicate Room Nominees Ltd | Professional & scientific | 2017 |
| Syndicateroom (TT) Nominees Ltd | Professional & scientific | 2015 |
| Syndicateroom TWENTY8 Nominees (TT) Limited | Professional & scientific | 2016 |
| Synergispace Ltd | Construction | 2025 |
| Synerglow Co., Ltd | Wholesale & retail | 2025 |
| Synergy Film Ltd | Information & communication | 2024 |