| Smart Blends Limited | Manufacturing | 2019 |
| Smart Metering Online LLP | | 2011 |
| Smartshop Traders Ltd | Wholesale & retail | 2020 |
| Smashbang Media Limited | Information & communication | 2015 |
| SMH Investment Writing Limited | Professional & scientific | 2016 |
| Smiling Sunto Trading Limited | Manufacturing | 2023 |
| Smithcad Limited | Professional & scientific | 2016 |
| Smokey Oakey's Mother | Arts & recreation | 2009 |
| Smooth AS Silk Limited | Other services | 2014 |
| Smooth Rentals Ltd | Professional & scientific | 2020 |
| SMP Building Limited | Construction | 2005 |
| Sniff & Bark Limited | Wholesale & retail | 2017 |
| Snipe Bar Limited | Hospitality | 2004 |
| Snitterfield Cricket Club Limited | Arts & recreation | 2021 |
| Snitterfield Sports Club Limited | Arts & recreation | 2002 |
| Snowdens Investments Limited | Real estate | 2018 |
| Snowrise Management Company One Limited | Extraterritorial | 1975 |
| Snowtorn Bear Limited | Extraterritorial | 2025 |
| Soko International Ltd | Information & communication | 2024 |
| Solarvision Lighting Technologies Limited | Construction | 2021 |
| Solo Chair Ltd | Other services | 2025 |
| Solutions & Resource Ltd | Real estate | 2017 |
| Some Agency Ltd | Information & communication | 2020 |
| Sona Security Limited | Professional & scientific | 2020 |
| Sonia Saville Limited | Professional & scientific | 2020 |
| Sooper Books Ltd | Information & communication | 2020 |
| Sophie Oliver Jewellery Limited | Wholesale & retail | 2015 |
| Soprano Software Solutions Ltd | Information & communication | 2011 |
| Sorensons Motors Limited | Wholesale & retail | 1960 |
| Sorrento Holdings Ltd | Real estate | 2006 |
| Soulfire Media Ltd | Information & communication | 2024 |
| Source - Search Ltd | Administrative & support | 2019 |
| Source Design and Print Limited | Extraterritorial | 2012 |
| South West Chicken Sexers Limited | Agriculture & fishing | 2018 |
| Southam Composites Ltd | Manufacturing | 2016 |
| Sovereign AI Node Ltd | Information & communication | 2026 |
| Sovo Marketing Ltd | Information & communication | 2025 |
| Sozac Group Limited | Professional & scientific | 2019 |
| Spa Practice Ltd | Health & social care | 2015 |
| Space Housing Ltd | Real estate | 2023 |
| Spacetime Consulting Limited | Information & communication | 2018 |
| Sparcana Limited | Wholesale & retail | 2010 |
| Speare Consulting Ltd | Professional & scientific | 2024 |
| Specialised Logistics Limited | Information & communication | 2009 |
| SPECTRA365 Limited | Information & communication | 2019 |
| SPECTRA365 Medical Limited | Health & social care | 2024 |
| Spicer Properties Limited | Real estate | 2014 |
| Spiny's Stuff Ltd | Wholesale & retail | 2012 |
| Spires Music Ltd | Arts & recreation | 2005 |
| Spizz Media Ltd | Administrative & support | 2016 |
| Splimple Limited | Information & communication | 2002 |
| Split Tongue Productions Limited | Information & communication | 2026 |
| SPN Industries Company Ltd | Wholesale & retail | 2013 |
| Sports Investment Group Limited | Administrative & support | 2016 |
| Sportsmark Designs Limited | Manufacturing | 1949 |
| Spot on Idea Ltd | Professional & scientific | 2023 |
| SPR Technologies Limited | Information & communication | 2022 |
| Spuddy Software Ltd | Professional & scientific | 2018 |
| Square PEG Communications Ltd | Other services | 2007 |
| Square TEN Limited | Professional & scientific | 2005 |
| Squawkzone Ltd | Other services | 2025 |
| Squibblys Limited | Other services | 2019 |
| Squosh Software Limited | Extraterritorial | 2005 |
| SSD Event Services Ltd | Manufacturing | 2025 |
| ST Demetrios Catering Ltd | Hospitality | 2023 |
| ST Gregory's Pre-School Limited | Education | 2008 |
| ST. David's Terrace Management Limited | Other services | 2015 |
| Stage Audio Ltd | Arts & recreation | 2023 |
| Stalls Lifestyle Limited | Wholesale & retail | 2014 |
| Star Accounts Stratford Ltd | Professional & scientific | 2017 |
| Star Shine 2024 Limited | Other services | 2024 |
| Star Shop CV37 Ltd | Wholesale & retail | 2026 |
| Starc Consulting Limited | Construction | 2016 |
| Start Within Ltd | Health & social care | 2020 |
| Steami Products Ltd | Wholesale & retail | 2026 |
| Steering Care Limited | Transport & logistics | 2023 |
| Stellar Technology Consulting Ltd | Information & communication | 2024 |
| Stemvita Ltd | Professional & scientific | 2016 |
| Stephen Walton Limited | Other services | 2017 |
| Stephens Premier Meats Limited | Wholesale & retail | 2012 |
| Sterilizer Technical Services Limited | Other services | 1998 |
| Steve Adams Limited | Professional & scientific | 2007 |
| Steve Deeks Limited | Professional & scientific | 1999 |
| Steven Holloway Limited | Administrative & support | 2003 |
| Stewart Moore Property Investment Limited | Real estate | 2003 |
| Stirra Limited | Real estate | 1943 |
| Stockbud Ltd | Information & communication | 2025 |
| Stockwell Estates Ltd | Households | 2024 |
| Stoke Park Finance Limited | Financial services | 1992 |
| Stolen Moon Ltd | Wholesale & retail | 2025 |
| Stonehampton IP Law Limited | Professional & scientific | 2021 |
| Stoneleigh Process Plant Limited | Professional & scientific | 2012 |
| Stonewood Trading Ltd | Wholesale & retail | 2011 |
| Stoneycroft Limited | Real estate | 2020 |
| Storenation Self Storage Ltd | Transport & logistics | 2025 |
| Stormforce Alarm Distribution Ltd | Water & waste | 2025 |
| Stour Valley Properties Limited | Real estate | 2017 |
| Stourcroft Limited | Construction | 2025 |
| Strategic Business Development & Support Limited | Administrative & support | 2012 |
| Stratford 27 Storage Solutions UK Ltd | Other services | 2020 |