| SES Secure Limited | Information & communication | 1998 |
| Seth Catering Limited | Hospitality | 2025 |
| Setter Ventures Limited | Real estate | 2025 |
| Seven Hills Orthopaedics Limited | Health & social care | 2018 |
| Sevenpoynt Ltd | Wholesale & retail | 2024 |
| Sevenshoots Ltd | Arts & recreation | 2016 |
| Sevenwise Advisory Limited | Professional & scientific | 2026 |
| SEW Woolly Limited | Wholesale & retail | 2025 |
| SF and K Ltd | Real estate | 2020 |
| SFA Legacy Investments Ltd | Wholesale & retail | 2025 |
| SFR Medical Limited | Health & social care | 2014 |
| SG Healthcare Services Limited | Health & social care | 2017 |
| SH Legal Services Limited | Professional & scientific | 2013 |
| Shaan Consulting Services Ltd | Professional & scientific | 2025 |
| Shafam Investment Limited | Real estate | 2023 |
| Shake Clinical Ltd | Information & communication | 2024 |
| Shapwick House LLP | | 2006 |
| Shaqavelli Services Ltd | Transport & logistics | 2026 |
| Sharif Breast Services Limited | Health & social care | 2013 |
| Sharma Paediatric Ltd | Health & social care | 2019 |
| SHE Health Clinic Ltd | Health & social care | 2026 |
| Shelbourne Estates Management LLP | | 2008 |
| Shelf Properties Limited | Real estate | 2020 |
| Shepherds Fold (Management Company) Limited | Households | 2017 |
| Sherbrook Development Co Limited | Construction | 1987 |
| Sherrington Programme Consultants (SPC) Ltd | Professional & scientific | 2008 |
| Shianjoy Ltd | Real estate | 2023 |
| Shimmering Forest Ltd | Hospitality | 2023 |
| Shizl Limited | Professional & scientific | 2021 |
| Shopjoy Limited | Wholesale & retail | 2025 |
| Short Technical Services Ltd | Wholesale & retail | 2019 |
| Shoulderdoc Limited | Wholesale & retail | 2004 |
| Shout Financial Solutions Limited | Professional & scientific | 2009 |
| Sibs&Co Ltd | Other services | 2025 |
| Siddaway Clinical Psychology Services Ltd | Health & social care | 2021 |
| Siddy Motors Limited | Professional & scientific | 2025 |
| SIDINGS3 Limited | Administrative & support | 2021 |
| Siematic UK Limited | Manufacturing | 2024 |
| Sigma Analysis Limited | Professional & scientific | 1996 |
| Sigmadoc Ltd | Health & social care | 2023 |
| Signallingrailway Ltd | Construction | 2025 |
| Signature Consulting Limited | Information & communication | 2015 |
| Signed Sealed Delivered Gifts Limited | Wholesale & retail | 2021 |
| Silk Anaesthesia LLP | | 2026 |
| Simben Surgical Ltd | Health & social care | 2023 |
| Simillis Limited | Health & social care | 2025 |
| Simlai Developments Limited | Construction | 2025 |
| Simmonds Health Ltd | Health & social care | 2022 |
| Simnett Holdings Limited | Financial services | 2026 |
| Simnett Properties Limited | Real estate | 2026 |
| Simon Heppell Plastic Surgery Limited | Health & social care | 2020 |
| Simon Lloyd Consultancy Limited | Professional & scientific | 2024 |
| Simply Argan Limited | Wholesale & retail | 2010 |
| Simply Beauty by Dana Limited | Other services | 2021 |
| Simply Beauty Wilmslow Limited | Other services | 2018 |
| Simplymyhealth Limited | Health & social care | 2025 |
| Simpson Communications Ltd | Information & communication | 2025 |
| Simpson Health Ltd | Health & social care | 2013 |
| Sinclair Family Law Limited | Financial services | 2026 |
| Sinclair Hughes Ltd | Professional & scientific | 2011 |
| Sinclair Innovation Ltd | Administrative & support | 2017 |
| Sinfonia Asset Management Limited | Financial services | 2007 |
| Sinus and Skull Base Limited | Health & social care | 2022 |
| Sirenis Pathways Ltd | Health & social care | 2025 |
| Sirius Sourcing Ltd | Wholesale & retail | 2013 |
| Sisla Investments Ltd | Real estate | 2025 |
| Sisu Psychology Limited | Health & social care | 2016 |
| Sitb Limited | Health & social care | 2019 |
| Sitescan North West Ltd | Professional & scientific | 2014 |
| Sitescan Surveys Ltd | Professional & scientific | 2012 |
| SJ Audio Limited | Information & communication | 2021 |
| SJ Imaging Limited | Health & social care | 2019 |
| SJ Matthews Ltd | Other services | 2014 |
| SJ PAY Limited | Administrative & support | 2010 |
| Sjbjbb Limited | Information & communication | 2025 |
| SJF Gill Limited | Health & social care | 2026 |
| SJK Healthcare Recruitment Limited | Administrative & support | 2025 |
| SJT Procurement Consulting Limited | Professional & scientific | 2014 |
| SK Pro 1 Ltd | Real estate | 2025 |
| SK Surgery Ltd | Health & social care | 2016 |
| SK9N Ltd | Wholesale & retail | 2022 |
| SKA & BP Consulting Limited | Health & social care | 2025 |
| Skanda Viva Limited | Health & social care | 2022 |
| SKG Anaesthesia Ltd | Health & social care | 2021 |
| Skil Marketing Ltd | Extraterritorial | 2009 |
| Skin Esthetique Limited | Health & social care | 2022 |
| Skogstad Limited | Wholesale & retail | 2011 |
| Skpartybus Limited | Transport & logistics | 2026 |
| Sky Shots Surveys Ltd | Construction | 2016 |
| Skynet Consulting Ltd | Information & communication | 2014 |
| Skyward Properties Ltd | Real estate | 2024 |
| Slater Dermatology Ltd | Health & social care | 2021 |
| SLB Newco Limited | Information & communication | 2024 |
| Slickmove Limited | Real estate | 2005 |
| Sloan FUN Fest Limited | Arts & recreation | 2017 |
| SM Associates Ltd | Administrative & support | 2016 |
| SM Fortress Ltd | Financial services | 2023 |
| SM Legal Advisers Limited | Professional & scientific | 2025 |
| Smaart Commercial Limited | Real estate | 2021 |
| Smart Building Finance Ltd | Financial services | 2024 |