| Shelley Estates Limited | Real estate | 2019 |
| Shelly Academy of Dance Limited | Education | 2002 |
| Shenton Woodcraft Limited | Wholesale & retail | 2022 |
| Shergill Productions Limited | Extraterritorial | 2012 |
| Sherwins Transport Limited | Manufacturing | 2016 |
| Shidaa Limited | Health & social care | 2025 |
| Shiltonarms Limited | Hospitality | 2026 |
| Shiv IT Ltd | Information & communication | 2013 |
| Shivam Computer Services Limited | Information & communication | 2014 |
| SHM Holidays Ltd | Real estate | 2021 |
| Shodu Property Ltd | Real estate | 2020 |
| Shoolin Group Limited | Professional & scientific | 2017 |
| Shop and Save Coventry Ltd | Wholesale & retail | 2024 |
| Show Jumping UK Limited | Arts & recreation | 2014 |
| Shree Infotech Ltd | Information & communication | 2020 |
| Shree Krishna Stores Limited | Wholesale & retail | 2021 |
| Shreeji Homes Ltd | Real estate | 2019 |
| Shreeji Property Services Ltd | Real estate | 2021 |
| Shrewd Global Consultancy Ltd | Transport & logistics | 2023 |
| Shreyas Homes Ltd | Real estate | 2017 |
| Shubhra Medical Services Limited | Health & social care | 2010 |
| Shumk Limited | Health & social care | 2022 |
| Shytec Fleet Maintenance and Services Ltd | Wholesale & retail | 2016 |
| SI Optical Ltd | Health & social care | 2016 |
| SI Plan Electronics Limited | Manufacturing | 1974 |
| Siana Limited | Transport & logistics | 2017 |
| Siara Catering Ltd | Hospitality | 2025 |
| Siddhvin Ltd | Construction | 2020 |
| Sidhom Consultancy Ltd | Information & communication | 2010 |
| Siemag Tecberg UK Limited | Professional & scientific | 2014 |
| Sifab Limited | Manufacturing | 2015 |
| Sigline Logistics Ltd | Transport & logistics | 2018 |
| Signature Property Services UK Limited | Construction | 2018 |
| Signpost Brewery Ltd | Manufacturing | 2018 |
| Siim Ltd | Information & communication | 2004 |
| Silkroute Developments Limited | Construction | 2026 |
| Silver Joy Healthcare Limited | Health & social care | 2022 |
| Silver Lobster Limited | Professional & scientific | 2011 |
| Silver Tree Books Limited | Wholesale & retail | 2010 |
| Silverage Professionals Ltd | Information & communication | 2023 |
| Silverdale Gardens Management Company Limited | Real estate | 2014 |
| Silverleaf Accountants Limited | Extraterritorial | 2020 |
| Silverleaf Advisory Limited | Professional & scientific | 2018 |
| Silverleaf Group Limited | Financial services | 2020 |
| Silverleaf Tax Limited | Professional & scientific | 2020 |
| Sim-Tech Solutions Ltd | Professional & scientific | 2010 |
| Sime Trans Limited | Transport & logistics | 2016 |
| Simha Properties Limited | Real estate | 2025 |
| Simon Coates Photography Ltd | Professional & scientific | 2008 |
| Simon Galt Limited | Administrative & support | 2003 |
| Simon Price Consulting Ltd | Professional & scientific | 2018 |
| Simple Facilities Management Limited | Other services | 2019 |
| Simplicity Tanning Studio Ltd | Other services | 2025 |
| Simplify Electrification Limited | Information & communication | 2024 |
| Simply Essentials Ltd | Wholesale & retail | 2011 |
| Simply Food Deli Limited | Wholesale & retail | 2023 |
| Simplywise Ltd | Financial services | 2021 |
| Simprit Healthcare Limited | Health & social care | 2022 |
| Simpson and Haig Homes Limited | Construction | 2023 |
| Sims Haulage Limited | Transport & logistics | 2014 |
| Simtech Engineering & Safety Services Ltd | Professional & scientific | 2012 |
| Simulario Ltd | Information & communication | 2024 |
| Simutec Ltd | Manufacturing | 2012 |
| Singleton Consulting Ltd | Administrative & support | 2009 |
| Singotarma RPA Ltd | Information & communication | 2025 |
| Sinis Transport Ltd | Transport & logistics | 2019 |
| Sintech Ltd | Professional & scientific | 2005 |
| Sirius a Corporation Limited | Professional & scientific | 2018 |
| Sirius Aerospace Manufacturing Limited | Manufacturing | 1994 |
| Sirius Manufacturing Group Holdings Limited | Professional & scientific | 1998 |
| Sirius Manufacturing Group Limited | Wholesale & retail | 2021 |
| Sirius Project Engineering Limited | Manufacturing | 1979 |
| Sirius Recruitment Services Limited | Administrative & support | 2023 |
| Sirontech Limited | Information & communication | 1992 |
| Sisho Decoration Ltd | Manufacturing | 2020 |
| Sislin IT Consulting Limited | Information & communication | 2018 |
| Sister ACT Limited | Other services | 2005 |
| Site Mapping Ltd | Professional & scientific | 2017 |
| Site Vision Surveys Limited | Administrative & support | 2003 |
| Sitesafetyservices.Com Ltd | Administrative & support | 2014 |
| Sivaamathi Ltd | Hospitality | 2024 |
| Sizzle BUN Ltd | Hospitality | 2026 |
| SJ Equity (UK) Limited | Financial services | 2025 |
| SJ Rentals Ltd | Administrative & support | 2025 |
| SJB Plant Limited | Construction | 2016 |
| SJB Plastering and Rendering Ltd | Construction | 2021 |
| SJE Corporate Events (UK) Limited | Professional & scientific | 2012 |
| SJG Consultancy Services Limited | Professional & scientific | 2009 |
| Skeet HR Consultancy Ltd | Administrative & support | 2025 |
| Ski-Ibo Ltd | Information & communication | 2023 |
| Skill Matrix Solutions Limited | Information & communication | 2017 |
| Skillforge Solutions Ltd | Administrative & support | 2024 |
| SKIN2U Ltd | Health & social care | 2025 |
| Skinsation Aesthetics Limited | Health & social care | 2024 |
| Skippys Plumbing and Handyman Ltd | Construction | 2021 |
| Skoon Beauty Ltd | Wholesale & retail | 2026 |
| Skrg Consultants Limited | Professional & scientific | 2016 |
| SKS Trading Ltd | Wholesale & retail | 2018 |
| Sks&S Ltd | Administrative & support | 2023 |
| Sky Blue Labour Limited | Construction | 2016 |