| Sharkey's Minibus Services Limited | Transport & logistics | 2023 |
| Sharp Electrical Contractors Limited | Wholesale & retail | 1989 |
| Sharp Research Ltd | Professional & scientific | 2010 |
| Sharp Trans Limited | Transport & logistics | 2012 |
| Shaw Associates (UK) Limited | Construction | 2006 |
| Shawn Wang Limited | Hospitality | 2013 |
| Sheila's Cake Creations Ltd | Manufacturing | 2020 |
| Shelagh Care Services Ltd | Health & social care | 2021 |
| Shellies Ltd | Wholesale & retail | 2023 |
| Shelterfirst Residentials Ltd | Health & social care | 2016 |
| Shepherd Assets Ltd | Real estate | 2024 |
| Shepherd Commercial Assets Ltd | Real estate | 2025 |
| Sherwood Mews Residents Association Limited | Households | 2003 |
| Shewit Investments Limited | Information & communication | 2012 |
| Shield Protection Ltd | Transport & logistics | 2024 |
| Shift UP NOW Ltd | Wholesale & retail | 2025 |
| Shiloh Supported Living Ltd | Health & social care | 2023 |
| Shina Studios Ltd | Information & communication | 2025 |
| Shinevantage Ltd | Wholesale & retail | 2025 |
| Shippii Holding Limited | Information & communication | 2018 |
| Shoggun Cleaning Ltd | Administrative & support | 2017 |
| Shoot for the Moon Education Ltd | Education | 2018 |
| Shop Fit Solutions Ltd | Construction | 2025 |
| SHOPFITTINGS2GO Ltd | Wholesale & retail | 2026 |
| Shopnsave.Amz Ltd | Wholesale & retail | 2023 |
| Short Producer Ltd | Information & communication | 2026 |
| Shoskycare Limited | Education | 2025 |
| Show Stars Theatre Company Limited | Arts & recreation | 2022 |
| Shrooq Healthcare Limited | Wholesale & retail | 2026 |
| Shumon Ahmed Ltd | Transport & logistics | 2024 |
| Shunem Care Limited | Hospitality | 2009 |
| SIA Optical Limited | Wholesale & retail | 2023 |
| Sia&Gi Services Ltd | Administrative & support | 2025 |
| Siaa Group Ltd | Real estate | 2025 |
| Siavs (UK) Ltd | Administrative & support | 2013 |
| Sicss Limited | Construction | 2019 |
| Sidhu & SON Residentials Limited | Real estate | 2026 |
| Sidney & SON Ltd | Construction | 2018 |
| Sidonia Bernardi Ltd | Professional & scientific | 2018 |
| Sierra Garage Limited | Wholesale & retail | 2019 |
| Sierra Vista Property Ltd | Real estate | 2024 |
| SIG Trans Ltd | Transport & logistics | 2019 |
| Sightworld Ltd | Health & social care | 2021 |
| Signal AI Ltd | Information & communication | 2025 |
| Signature Hall Limited | Real estate | 2026 |
| Signature Motor Works Ltd | Wholesale & retail | 2026 |
| Signature Plumbing Co Limited | Construction | 2026 |
| Signature Tanning Limited | Professional & scientific | 2019 |
| Signet Corporation Ltd | Wholesale & retail | 2012 |
| Signet Homes Limited | Real estate | 2016 |
| Signet Housing & Support Services Ltd | Hospitality | 2023 |
| Silent Italian Limited | Extraterritorial | 2014 |
| Siluan Ltd | Construction | 2019 |
| Silvan Transporter Ltd | Transport & logistics | 2024 |
| Silver House Construction Ltd | Construction | 2020 |
| Silverflair Holdings Limited | Financial services | 2024 |
| Silverton Limited | Hospitality | 2017 |
| SIM Cabs 24/7 Ltd | Transport & logistics | 2025 |
| Simadee Consultancy Limited | Information & communication | 2017 |
| Simaribeauty Ltd | Health & social care | 2019 |
| Simary Limited | Information & communication | 2008 |
| Simco Auto Ltd | Wholesale & retail | 2023 |
| Simo MAX Limited | Transport & logistics | 2026 |
| Simon Arthur Maintenance Ltd | Professional & scientific | 2025 |
| Simon Horner Consultancy Limited | Construction | 2015 |
| Simone Ethan Ltd | Households | 2025 |
| Simple Caring Solutions Limited | Health & social care | 2016 |
| Simply Property Lettings Ltd | Real estate | 2020 |
| Simply Property Services Ltd | Real estate | 2020 |
| Simplyjoy Ltd | Wholesale & retail | 2018 |
| Simsto Ltd | Hospitality | 2023 |
| Sinclair Electrical Contractors Limited | Construction | 2011 |
| Sinclair's Natural Hair Care Ltd | Manufacturing | 2025 |
| Singh Renewables Limited | Financial services | 2022 |
| Sirbu Civils Ltd | Construction | 2026 |
| Sirbutransport Ltd | Construction | 2020 |
| Sirocco Mechanical Limited | Extraterritorial | 2023 |
| Sirus Logistics UK Ltd | Transport & logistics | 2025 |
| Sisters&Co Events Ltd | Hospitality | 2022 |
| Site Contract Solutions Limited | Professional & scientific | 2019 |
| Sitra Building Services Limited | Construction | 2016 |
| Sitra Electrical Ltd | Construction | 2008 |
| SIV Prop Ltd | Real estate | 2019 |
| Sizewell Aggregates Limited | Extraterritorial | 2022 |
| Sizzled Lakeside Limited | Hospitality | 2014 |
| SJ Quality Construction Ltd | Construction | 2017 |
| SJA Services Ltd | Construction | 2017 |
| SK & TG Ltd | Real estate | 2025 |
| SK Advisory Services Ltd | Financial services | 2019 |
| Skay Limited | Information & communication | 2008 |
| SKC Radians Ltd | Administrative & support | 2020 |
| Skin SO Sweet Limited | Manufacturing | 2019 |
| Skinlab Medical Ltd | Wholesale & retail | 2018 |
| Skintility Ltd | Extraterritorial | 2024 |
| SKK Convenience Ltd | Wholesale & retail | 2026 |
| SKM & SON Haulage Limited | Transport & logistics | 2008 |
| Skma Business Services Ltd | Education | 2014 |
| Skma Group Ltd | Wholesale & retail | 2017 |
| Skoles Resources Limited | Information & communication | 2019 |
| Skorski Transport Ltd | Transport & logistics | 2018 |