| Shirley Estates (Developments) Limited | Professional & scientific | 1990 |
| Shirley Home Learning Ltd | Education | 2021 |
| Shirley Kebab and Fish Ltd | Hospitality | 2024 |
| Shirley Mini Market Ltd | Wholesale & retail | 2026 |
| Shirley Old People's Welfare Committee Limited | Health & social care | 2014 |
| Shirley Postal Services Ltd | Transport & logistics | 2022 |
| Shirley Town Barbers Ltd | Other services | 2016 |
| Shiv Developers Ltd | Real estate | 2021 |
| Shiva Global Limited | Wholesale & retail | 2026 |
| Shivshakti Housing Limited | Real estate | 2022 |
| Shoaib Consultancy Ltd | Professional & scientific | 2022 |
| Shoestring Toys Ltd | Wholesale & retail | 2025 |
| Shoppertrak Limited | Other services | 1987 |
| Shore Rentals Ltd | Real estate | 2022 |
| Shorton Property LLP | | 2011 |
| Shots by Hanif Ltd | Information & communication | 2021 |
| SHR Locum Limited | Health & social care | 2025 |
| Shree DMS Limited | Health & social care | 2011 |
| Shree SDM Ltd | Health & social care | 2020 |
| Shree Siddhivinayak Ventures Ltd | Hospitality | 2025 |
| Shreejay Service Ltd | Wholesale & retail | 2025 |
| Shreeji Baps Limited | Wholesale & retail | 2025 |
| Shriguru Consulting Ltd. | Information & communication | 2016 |
| Shrunkies Ltd | Arts & recreation | 2010 |
| Shush (UK) Limited | Manufacturing | 2001 |
| Shuvo & Co Holdings Limited | Real estate | 2019 |
| Shuvo Developments Limited | Real estate | 2019 |
| SI Project Chambers Ltd | Real estate | 2023 |
| SI Project Pinnacles Ltd | Real estate | 2023 |
| Sibc Property Company Limited | Arts & recreation | 1996 |
| Sibc Trading Limited | Arts & recreation | 1996 |
| SIC Distribution Ltd | Wholesale & retail | 2021 |
| Side Hustle Together Limited | Information & communication | 2026 |
| Sideway Park Management Company Limited | Real estate | 2015 |
| Sidney James Limited | Professional & scientific | 2020 |
| SIG 21 Ltd | Real estate | 2021 |
| SIG 23 Ltd | Real estate | 2021 |
| SIG 25 Ltd | Real estate | 2022 |
| SIG 26 Ltd | Real estate | 2023 |
| SIG 27 Ltd | Real estate | 2023 |
| SIG 30 Ltd | Real estate | 2024 |
| SIG 40 Ltd | Real estate | 2023 |
| Sigma Innovations Ltd | Hospitality | 2024 |
| Sigma Shift Ltd | Professional & scientific | 2026 |
| Sigmaop Consulting Limited | Professional & scientific | 2025 |
| Sigmasis UK Limited | Wholesale & retail | 2023 |
| Sign Art Installations Ltd | Construction | 2023 |
| Signal Engineering Solutions UK Limited | Professional & scientific | 2010 |
| Signal Hayes (Walmley) Limited | Construction | 2024 |
| Signatura & Co. Limited | Wholesale & retail | 2025 |
| Signature Campers Ltd | Wholesale & retail | 2025 |
| Signature Hire Limited | Administrative & support | 2009 |
| Signature Limited | Extraterritorial | 1982 |
| Signpost Solutions Limited | Manufacturing | 1972 |
| Sigum Ltd | Construction | 2022 |
| Sihe Trading Ltd | Wholesale & retail | 2024 |
| Silent Wonders Ltd | Information & communication | 2026 |
| Silhill 17 Limited | Financial services | 2025 |
| Silhill Financial Services Limited | Administrative & support | 2010 |
| Silhill Medical Services Limited | Health & social care | 2014 |
| Silhill Resources Limited | Construction | 2020 |
| Silhillians Rugby Union Football Club | Arts & recreation | 2017 |
| Sillan Properties Ltd | Real estate | 2025 |
| Silplas Building Products Limited | Extraterritorial | 1996 |
| Silvafin Developments Ltd | Construction | 2023 |
| Silver Aero Limited | Financial services | 2019 |
| Silver Birch Carpentry & Joinery Ltd | Construction | 2022 |
| Silver Blakeman Events Limited | Financial services | 2018 |
| Silver Cherry Limited | Wholesale & retail | 2005 |
| Silver Innovation Ltd | Information & communication | 2009 |
| Silver Oak Enterprise Management Ltd | Wholesale & retail | 2025 |
| Silver Wolf Productions LLP | | 2025 |
| Silverline Landflight Limited | Transport & logistics | 1994 |
| Silverline Vending Ltd | Wholesale & retail | 2025 |
| Silversword Properties Limited | Construction | 2002 |
| SIM Game Umberslade Ltd | Arts & recreation | 2021 |
| Simbio Suit Ltd | Professional & scientific | 2023 |
| Simception Limited | Information & communication | 2015 |
| Simcoll Lmetd Limited | Construction | 2016 |
| Simlar 2 Cosmetics Limited | Wholesale & retail | 2022 |
| Simmonds Precision Limited | Manufacturing | 1988 |
| Simon C Evans Ltd | Health & social care | 2012 |
| Simon Featherstone Consulting Ltd | Professional & scientific | 2016 |
| Simon Parsons Executive Recruitment Limited | Administrative & support | 2017 |
| Simpkin James Developments Ltd | Real estate | 2024 |
| Simpkins Industry & Advisory Limited | Information & communication | 2024 |
| Simple Couriers Limited | Transport & logistics | 2016 |
| Simple Printing Ltd | Wholesale & retail | 2017 |
| Simplex Conduit Systems Limited | Extraterritorial | 2013 |
| Simplistik Ltd | Real estate | 2022 |
| Simply Allsorts Ltd | Wholesale & retail | 2014 |
| Simply Courchevel Limited | Administrative & support | 2016 |
| Simply Group NE Limited | Construction | 2019 |
| Simply Just Nutrition Limited | Health & social care | 2016 |
| Simply Tech Ltd | Wholesale & retail | 2017 |
| Simply Tignes Limited | Administrative & support | 2016 |
| Simply VAL D'Isere Limited | Administrative & support | 2016 |
| Simplyswimming Limited | Education | 2016 |
| Sinaiya Enterprises Limited | Real estate | 2025 |
| Sincere Homes (Kidderminster) Limited | Real estate | 2019 |