| Show Sport Entertainment Limited | Arts & recreation | 2012 |
| Showbiz Entertainment Limited | Professional & scientific | 2005 |
| SI Chamberlain Limited | Other services | 2020 |
| SI Electrical & Security Ltd | Construction | 2023 |
| Siam Control and Automation Limited | Manufacturing | 2008 |
| Signature Scapes Limited | Administrative & support | 2022 |
| Signzworld Ltd | Administrative & support | 2011 |
| Silhill Consulting Limited | Professional & scientific | 2024 |
| Silvaque Holdings Limited | Professional & scientific | 2016 |
| Silver Birches Home Boarding Ltd | Other services | 2025 |
| Silver Swan Beds Limited | Wholesale & retail | 2016 |
| Silverline Property Management Limited | Real estate | 2024 |
| Silverstone Mortgages Ltd | Financial services | 2020 |
| Silverstone Wealth Management Limited | Financial services | 2020 |
| Sima Service Ltd | Administrative & support | 2018 |
| Simon Brew Limited | Information & communication | 2011 |
| Simon Peaford Limited | Administrative & support | 2008 |
| Simple Psychiatry Solutions Ltd | Health & social care | 2021 |
| Simply Dataworks Ltd | Information & communication | 2024 |
| Simportal AS a Service Limited | Information & communication | 2022 |
| Siobhan Mcdermott Ltd | Information & communication | 2023 |
| Sipm Services Limited | Professional & scientific | 2009 |
| Sirius Facades Limited | Construction | 2013 |
| Siro Training and Consultancy Solutions Limited | Professional & scientific | 2023 |
| Siros Design Ltd | Wholesale & retail | 2017 |
| Site Management Services (Central) Ltd. | Construction | 2000 |
| Site Safe Security Ltd | Administrative & support | 2026 |
| Sitewatch Security Limited | Extraterritorial | 2010 |
| Sivic Investments Limited | Professional & scientific | 2008 |
| SIX Wands Aspects Limited | Professional & scientific | 2017 |
| SIX Wands Ltd | Extraterritorial | 2025 |
| Sixth Workwear Limited | Wholesale & retail | 2021 |
| SJ Cars and Recovery Ltd | Wholesale & retail | 2025 |
| SJ Corp Ltd | Wholesale & retail | 2026 |
| SJ Properties (Midlands) Limited | Real estate | 2018 |
| Sjrc Investments | Professional & scientific | 2016 |
| Sjrc Partners | Professional & scientific | 2016 |
| Sjrp Holdings Limited | Financial services | 2025 |
| Sjrp Investments 2023 Limited | Financial services | 2023 |
| Sjrp Investments Ltd | Financial services | 2013 |
| SJW Services Ltd | Professional & scientific | 2025 |
| Skelly's Rules Ltd | Administrative & support | 2024 |
| SKG Interiors Ltd | Manufacturing | 2023 |
| SKH Express Limited | Wholesale & retail | 2023 |
| Skil Builders Limited | Construction | 2008 |
| Skilled Properties Limited | Real estate | 2014 |
| Skillvator Ltd | Education | 2021 |
| SKS Decorating Solutions Ltd | Construction | 2016 |
| Skum Town Records Ltd | Information & communication | 2024 |
| Sky Blue Purchasing, Developments and Design Limited | Information & communication | 1999 |
| Sky House Restaurant Limited | Hospitality | 2022 |
| Skyarna Limited | Professional & scientific | 2010 |
| Skymingo Ltd | Administrative & support | 2024 |
| Skyplus Travels and Tours Limited | Administrative & support | 2020 |
| Skyrai Consulting Ltd | Professional & scientific | 2025 |
| Skånsom Limited | Construction | 2025 |
| SL17 Solutions Limited | Information & communication | 2014 |
| Slemcka (DMS) Holdings Limited | Financial services | 2024 |
| Slice of America Limited | Hospitality | 2022 |
| Slss Group Holdings Ltd | Financial services | 2025 |
| Slss Leisure Ltd | Financial services | 2024 |
| SM Khaula Consultancy Limited | Professional & scientific | 2025 |
| SM Retail Online Ltd | Manufacturing | 2018 |
| Small Cars R US Limited | Wholesale & retail | 2017 |
| Smart Hygiene Solutions Ltd | Construction | 2021 |
| Smart Tech Trade Ltd | Wholesale & retail | 2020 |
| Smart Temps Limited | Administrative & support | 2016 |
| Smartech Installations Ltd | Construction | 2024 |
| Smartlead Marketing Limited | Professional & scientific | 2022 |
| Smartwares Safety & Lighting Limited | Wholesale & retail | 1949 |
| Smbs Healthcare Ltd | Administrative & support | 2017 |
| SMH Resale Ltd | Wholesale & retail | 2023 |
| Smith & FOX Building and Landscaping Solutions Ltd | Construction | 2025 |
| SMJ National Ltd | Construction | 2026 |
| Smokeduk Ltd | Wholesale & retail | 2025 |
| SMT (Midlands) Limited | Manufacturing | 2009 |
| Snowball Smith Medical Services Ltd | Health & social care | 2020 |
| Snugglepets & Co Ltd | Wholesale & retail | 2022 |
| Social Arch Ltd | Information & communication | 2023 |
| Social Rivals Ltd | Information & communication | 2023 |
| Socotrans Ltd | Transport & logistics | 2016 |
| Softlife Kitchen Limited | Hospitality | 2026 |
| Sofwan Ltd | Professional & scientific | 2025 |
| Sole Sanctuary Ltd | Health & social care | 2022 |
| Soley Cleans Ltd | Other services | 2023 |
| Solid Rock Properties Oxford Limited | Construction | 2015 |
| Solid Stone Works Ltd | Manufacturing | 2025 |
| Solihull Windows and Conservatories Limited | Wholesale & retail | 2008 |
| Solihull Windows and Doors Limited | Extraterritorial | 2013 |
| Solihull Windows Limited | Extraterritorial | 2013 |
| Solo Home Care Ltd | Health & social care | 2026 |
| Solon Systems Limited | Manufacturing | 2006 |
| Solutions 4 IT Limited | Information & communication | 1998 |
| Solutions 4 Wifi Limited | Information & communication | 2014 |
| Solutions Digital Ltd | Extraterritorial | 2009 |
| Solutions Retail Displays Ltd | Extraterritorial | 2019 |
| Solutions Retail Ltd | Extraterritorial | 2019 |
| Somerleyton Court Residents' Management Limited | Households | 1997 |
| Somers Forge Limited | Manufacturing | 1949 |
| Somers Square Dental Laboratory Limited | Manufacturing | 2025 |