| SLC Site Support & Transport Ltd | Transport & logistics | 2016 |
| SLC Surrey Limited | Real estate | 2019 |
| Sleek Sheen Services Ltd | Wholesale & retail | 2025 |
| Slinky Pinks Limited | Wholesale & retail | 2018 |
| SLJ Records Ltd | Information & communication | 2025 |
| SLP Data Consulting Ltd | Information & communication | 2026 |
| Slumpi Ltd | Hospitality | 2018 |
| SM at Pleas Properties Ltd | Real estate | 2012 |
| SM Beardmore Ltd | Professional & scientific | 2018 |
| SM Interiors Limited | Other services | 2017 |
| Smag International Limited | Administrative & support | 2017 |
| Small Packages Property Ltd | Real estate | 2020 |
| Smallboy Consulting Limited | Professional & scientific | 2024 |
| Smart Automotive Specialists Ltd | Wholesale & retail | 2013 |
| Smart Build Interiors Ltd | Construction | 2026 |
| Smart Care Giver Limited | Health & social care | 2022 |
| Smart Fabric Maintenance (FM) Limited | Construction | 2024 |
| Smart Relocation Group Ltd | Real estate | 2018 |
| Smartech Trades Ltd | Wholesale & retail | 2026 |
| Smartkey Apartments Ltd | Real estate | 2022 |
| Smartly Build Limited | Real estate | 2023 |
| Smarttech Construction Ltd | Construction | 2022 |
| Smartway Cleaning Services Limited | Administrative & support | 2024 |
| Smash Entertainment Limited | Arts & recreation | 2024 |
| SMB Sport and Exercise Medicine Limited | Health & social care | 2013 |
| SMC Advisory Limited | Professional & scientific | 2025 |
| Smci Pharma Ltd | Public administration | 2013 |
| SME Evolutions Limited | Professional & scientific | 2019 |
| SME VC Limited | Financial services | 2002 |
| Smetco Ltd | Information & communication | 2025 |
| SMH Windows Ltd | Construction | 2020 |
| Smile Optics Limited | Health & social care | 2015 |
| Smith Pearman Holdings Limited | Professional & scientific | 2016 |
| SMN Distribution Ltd | Wholesale & retail | 2025 |
| SMOOTHBARGAIN4U Ltd | Wholesale & retail | 2022 |
| SMP Portfolio Limited | Real estate | 2026 |
| Smuve Limited | Wholesale & retail | 2020 |
| SN & Edgware LLP | | 2015 |
| Snack Press Ltd | Professional & scientific | 2021 |
| Snapgrc Limited | Information & communication | 2025 |
| Snappi Cart Ltd | Wholesale & retail | 2025 |
| Snayyar Properties Limited | Real estate | 2022 |
| Sndbx UK Limited | Administrative & support | 2025 |
| Snowburner Consultants Ltd | Other services | 2013 |
| Snug Services Ltd | Construction | 2022 |
| SO Consulting International Ltd | Professional & scientific | 2023 |
| SO Granola Co. Limited | Manufacturing | 2019 |
| SO WOT? Ltd | Wholesale & retail | 2025 |
| Soaphouse Ltd | Construction | 2021 |
| Socalled Ltd | Professional & scientific | 2010 |
| Socalm Hair Studio Ltd | Other services | 2025 |
| Socare Innovation Limited | Administrative & support | 2024 |
| Social Infrastructure Capital Limited | Financial services | 2025 |
| Social Pack Ltd | Professional & scientific | 2020 |
| Socialprotein Ltd | Wholesale & retail | 2026 |
| Sociavox Ltd | Information & communication | 2025 |
| Socket Electrical Ltd | Construction | 2021 |
| Soda Property Investments Ltd | Real estate | 2022 |
| Sodatch Ltd | Wholesale & retail | 2020 |
| Sofia Construction Services Ltd | Construction | 2025 |
| Sofl Funding III Limited | Financial services | 2017 |
| Sofl Funding IV Limited | Financial services | 2017 |
| Sofl Funding V Limited | Financial services | 2019 |
| Sofl Funding VI Limited | Financial services | 2023 |
| Softloud Limited | Information & communication | 2021 |
| Softronic Systems Limited | Information & communication | 2017 |
| Softronix Systems Limited | Information & communication | 1998 |
| Software Alliance Services Limited | Administrative & support | 2019 |
| Software Artists Ltd | Information & communication | 2018 |
| Software Consultancy Service Limited | Information & communication | 1986 |
| SOH Media (EU) Ltd | Professional & scientific | 2025 |
| Soirée Ltd | Hospitality | 2023 |
| Soledo Holdings Limited | Financial services | 2009 |
| Soledo Properties (UK) Limited | Real estate | 2010 |
| Soledo Properties Limited | Real estate | 1985 |
| Solestyle Wholesale Limited | Wholesale & retail | 2023 |
| Solid Associates Ltd | Wholesale & retail | 2018 |
| Solosound Ltd | Manufacturing | 2010 |
| Solou's Bakery Ltd | Manufacturing | 2023 |
| Something Big EOT Limited | Administrative & support | 2021 |
| Something Labs Ltd | Information & communication | 2026 |
| Sonia Friedman Productions Limited | Arts & recreation | 2001 |
| Sonia's Gardens Ltd | Construction | 2017 |
| Sonic Rentals Ltd | Real estate | 2025 |
| Sonic Sound Services Ltd | Information & communication | 2016 |
| Soniti Ltd | Information & communication | 2019 |
| Sonys Construction Ltd | Construction | 2015 |
| Sopheon Limited | Information & communication | 1996 |
| Sophie Sews Ltd | Manufacturing | 2018 |
| Sopra Business Consulting Limited | Information & communication | 2017 |
| Sopranos Ltd | Other services | 2023 |
| Sorella Hair & Beauty Ltd | Other services | 2016 |
| Sorted Life Ltd | Professional & scientific | 2020 |
| Sortplan Limited | Financial services | 1980 |
| Souches Logic Limited | Professional & scientific | 2011 |
| Sound Analysts Ltd | Information & communication | 2013 |
| Sound by Design Limited | Information & communication | 2019 |
| Souterpix Ltd | Professional & scientific | 2007 |
| South Coast Trading Group Ltd | Wholesale & retail | 2024 |
| South Downs Estimating Consultants Limited | Professional & scientific | 2013 |