| Seymours Walton-On-Thames Ltd | Real estate | 2022 |
| SF & Co Ltd | Wholesale & retail | 2014 |
| SG Learning Ltd | Education | 2026 |
| Sgdt Limited | Financial services | 2024 |
| SGM Medical Ltd | Health & social care | 2014 |
| SGP Assets Ltd | Real estate | 2026 |
| Shacklady Limited | Households | 2010 |
| Shahab Optical Ltd | Health & social care | 2020 |
| Shaji Limited | Health & social care | 2017 |
| Shala Property Investments Limited | Real estate | 2023 |
| Shalko Enterprise Limited | Wholesale & retail | 2025 |
| Shan Trading Company Limited | Wholesale & retail | 2025 |
| Shanghai Hospitality Limited | Hospitality | 2017 |
| Sharma Ventures Ltd | Health & social care | 2025 |
| Sharn Panesar Ltd | Hospitality | 2011 |
| Sharp & Flask Limited | Other services | 2015 |
| Sharp & Flask Westbourne Park Ltd | Other services | 2019 |
| Sharp Clean Limited | Administrative & support | 2020 |
| Sharpfilms Limited | Information & communication | 2018 |
| Shaun Brackenbury Limited | Transport & logistics | 2009 |
| Shay Communications Ltd | Information & communication | 2009 |
| Shbc Camberley Limited | Real estate | 2016 |
| SHE Sparkles Ltd | Professional & scientific | 2015 |
| Sheffbuild Ltd | Construction | 2013 |
| Shels Commercial Limited | Real estate | 2019 |
| Shels Investments Ltd | Administrative & support | 2017 |
| Shemey Stays Ltd | Real estate | 2025 |
| Shenzhen Trade Ltd | Wholesale & retail | 2024 |
| Shepley Property Developments Ltd | Construction | 2025 |
| Sherfield Road (Bramley) Management Company Limited | Households | 2018 |
| Sherlock Investment Group Limited | Financial services | 2026 |
| Sherwood Fire Ltd | Administrative & support | 2003 |
| Shift Perception Ltd | Professional & scientific | 2025 |
| Shiney Tees Ltd | Administrative & support | 2024 |
| Shingler Property Development Limited | Construction | 2012 |
| Shiny for YOU Ltd | Other services | 2019 |
| Shipton Protection Ltd | Financial services | 2025 |
| Shirefox Limited | Information & communication | 2024 |
| Shirol & Co Ltd | Real estate | 2025 |
| Shiv Kashi Ltd | Real estate | 2023 |
| Shligo Signalling Ltd | Construction | 2023 |
| Shoker Legal Services Ltd | Professional & scientific | 2017 |
| Shoma Crane Hire Limited | Administrative & support | 2023 |
| Shop Vera Limited | Wholesale & retail | 2026 |
| Shortland Builders Limited | Construction | 2023 |
| Shotang Limited | Households | 1982 |
| Shrees Food Limited | Hospitality | 2024 |
| Shreyansh and Shaan Limited | Real estate | 2025 |
| Shutterwild Expeditions Ltd | Professional & scientific | 2026 |
| Siarcotech Limited | Information & communication | 1999 |
| Sidewalk Management Limited | Households | 2000 |
| Siemens Healthcare Diagnostics Ltd | Manufacturing | 1995 |
| Siemens Healthcare Diagnostics Manufacturing Ltd | Manufacturing | 1985 |
| Siemens Healthcare Diagnostics Products Ltd | Manufacturing | 1986 |
| Siemens Healthcare Limited | Manufacturing | 2015 |
| Sigma Lance Corporation Limited | Health & social care | 2013 |
| Signal Group Limited | Manufacturing | 1978 |
| Signal Spud Ltd | Information & communication | 2026 |
| Signature Finance Services Ltd | Financial services | 2019 |
| Signmaking Developments Limited | Extraterritorial | 1987 |
| Signpost PM Solutions Limited | Information & communication | 2009 |
| Sigwood Carpentry Ltd | Construction | 2015 |
| SIK Properties Ltd | Real estate | 2022 |
| Silk Infinity Flowers Limited | Wholesale & retail | 2021 |
| Silva Associates LLP | | 2012 |
| Silver FIR Carpentry Limited | Manufacturing | 2019 |
| Silver Moon Estates Ltd | Real estate | 2016 |
| Silver Spoon PVT Ltd | Hospitality | 2026 |
| Silvera Property Management Ltd | Other services | 2024 |
| Silverline Accounting Services Ltd | Professional & scientific | 2026 |
| Silverstar Estates Limited | Real estate | 1999 |
| Silvester Crash Repair (Fairland) Ltd | Wholesale & retail | 2025 |
| Sily Travel-Chauffeur Ltd | Administrative & support | 2024 |
| Sim-Avionics Limited | Information & communication | 2011 |
| Simflex Consultancy Limited | Professional & scientific | 2017 |
| Simm Strategic Land Ltd | Professional & scientific | 2026 |
| Simon Dickens Ltd | Professional & scientific | 2021 |
| Simon Friend Retouching Ltd | Professional & scientific | 2014 |
| Simon Grove Travel Ltd | Extraterritorial | 2024 |
| Simon West Films Limited | Information & communication | 2016 |
| Simonprop Ltd | Arts & recreation | 2025 |
| Simplicity Healthcare Recruitment Limited | Administrative & support | 2022 |
| Simply Lets Limited | Extraterritorial | 1992 |
| Sing Wing Ltd | Real estate | 2024 |
| Sirch Ltd | Professional & scientific | 2021 |
| Sitol Tiling Contractors Limited | Construction | 2019 |
| Sixth Sense Resources Title Limited | Professional & scientific | 1996 |
| Sixtysixtyfour Limited | Manufacturing | 2012 |
| SJ2 Consulting Limited | Professional & scientific | 2009 |
| SJA Comms Ltd | Real estate | 2018 |
| SJB Autotech Limited | Wholesale & retail | 2010 |
| SJC Accounting Ltd. | Professional & scientific | 2018 |
| Skalsi Ltd | Health & social care | 2022 |
| Skdl Ltd | Manufacturing | 2021 |
| Skerryvore Hold Co Ltd | Financial services | 2019 |
| Skiextra Limited | Arts & recreation | 2007 |
| Skin Research Ltd | Wholesale & retail | 2011 |
| Skin Two Limited | Professional & scientific | 1986 |
| Skintuition Limited | Health & social care | 2015 |
| Skopic Limited | Real estate | 2020 |