| Soleasy Ltd | Construction | 2020 |
| Solid Roofing Services Ltd | Construction | 2012 |
| Solidscope Ltd | Professional & scientific | 2018 |
| Solis UK Consultants Limited | Professional & scientific | 2025 |
| Sollitt Legal Solutions Ltd | Professional & scientific | 2023 |
| Soloman Charles Contracting Ltd | Construction | 2018 |
| Soltierra UK Limited | Wholesale & retail | 2019 |
| Solutions Dbase Ltd | Real estate | 2012 |
| Solvend Group Limited | Wholesale & retail | 2024 |
| Solway House Limited | Health & social care | 2002 |
| Somemightsay (London) Limited | Arts & recreation | 2017 |
| Sonder Consultants Ltd | Administrative & support | 2018 |
| Soni Capital Ltd | Professional & scientific | 2023 |
| Sood Family Estates Ltd | Real estate | 2026 |
| Sophie Grey Ltd | Hospitality | 2010 |
| Sophie's Site Admin Limited | Administrative & support | 2022 |
| Sorba UK Limited | Construction | 1985 |
| Sorin Iobagi Ltd | Water & waste | 2025 |
| Sorustyc Ltd | Information & communication | 2026 |
| Soteria Insurance Limited | Financial services | 2020 |
| Soul 2 Care Ltd | Public administration | 2020 |
| Sound Choice Hire Limited | Professional & scientific | 2008 |
| Soundmind Therapy Limited | Health & social care | 2020 |
| Sounds and Scenes Ltd | Professional & scientific | 2020 |
| Sourced Digital Ltd | Information & communication | 2020 |
| Sourgrape London Limited | Manufacturing | 2018 |
| South Africa Supplies Ltd | Wholesale & retail | 2026 |
| South Coast Anodising Limited | Manufacturing | 2022 |
| South Coast Roast Coffee Limited | Hospitality | 2018 |
| South East Ballet Scholars Limited | Education | 2014 |
| South East Ducting Solutions Ltd | Construction | 2021 |
| South East Metals Ltd | Wholesale & retail | 2021 |
| South East Services Ltd | Administrative & support | 2017 |
| South Eastern Financial Services Ltd | Financial services | 2002 |
| South Eastern Solar Electrical Limited | Other services | 2010 |
| South Essex Plumbing and Heating Limited | Construction | 2022 |
| South Essex Primary Care Support Services Ltd. | Administrative & support | 2014 |
| South House Group Limited | Financial services | 2018 |
| South Street Romford (Block C) Management Company Limited | Households | 1989 |
| South Street Romford (Block F) Management Company Limited | Households | 1989 |
| South Street Romford (Block G) Management Company Limited | Households | 1989 |
| Southan Financials Ltd | Professional & scientific | 2019 |
| Southeast Electrical Construction Ltd | Construction | 2021 |
| Southeast Electrical Contractors Group Ltd | Construction | 2015 |
| Southeast Electrical Services Ltd | Wholesale & retail | 2015 |
| Southern (West) Padel Ltd | Other services | 2025 |
| Southern Optical Limited | Administrative & support | 2017 |
| Southfields Village Development Company Limited | Extraterritorial | 1996 |
| Southgreen Care Limited | Health & social care | 2007 |
| Sowas Consultancy Services Ltd | Professional & scientific | 2025 |
| Sozehikizer Limited | Information & communication | 2019 |
| SP Indago LLP | | 2008 |
| Spanish Education Ltd | Wholesale & retail | 2026 |
| Spark International Limited | Professional & scientific | 2015 |
| Sparrow Project Management Ltd | Administrative & support | 2007 |
| Spartans Agency Ltd | Information & communication | 2025 |
| Speak Property Consultancy Limited | Real estate | 2004 |
| Spearhavoc Fintech Limited | Information & communication | 2021 |
| Special Needs and Parents Limited | Health & social care | 1999 |
| Specialist Contracts Limited | Professional & scientific | 2003 |
| Specialist Freight Networks Ltd | Administrative & support | 2011 |
| Specialist Handrail Systems Ltd | Manufacturing | 2018 |
| Specialist Security Network Ltd | Other services | 2025 |
| Speech and Drama Academy Limited | Arts & recreation | 2020 |
| Speed Tapers UK Ltd | Construction | 2009 |
| Speedtime Limited | Real estate | 2015 |
| Speedy Banners Ltd | Manufacturing | 2020 |
| Spellbrook Driveways Ltd | Administrative & support | 2021 |
| Spellicious Ltd | Wholesale & retail | 2025 |
| Spence & Sawyer Properties Limited | Construction | 1997 |
| Spencer Court (Flats) Management Company Limited | Households | 1993 |
| Spencer Place Management Company Limited | Households | 1993 |
| Speywood Limited | Agriculture & fishing | 1993 |
| Sphere Constructions Ltd | Construction | 2016 |
| Spi-Des-Ign Web & Graphic Solutions Limited | Information & communication | 2012 |
| Spice Knight Ltd | Hospitality | 2011 |
| Spice Station Brentwood Ltd | Hospitality | 2018 |
| Spice Xpress Essex Ltd | Hospitality | 2026 |
| Spicy Pickleball Academy Ltd | Arts & recreation | 2025 |
| Spike Properties Limited | Real estate | 2012 |
| Spinal Care Building Limited | Real estate | 2023 |
| Spinal Care Clinics Holdings Limited | Financial services | 2022 |
| Spinal Care Clinics Limited | Health & social care | 2010 |
| Spiralis Limited | Other services | 2009 |
| Spires Consultancy Limited | Manufacturing | 1999 |
| Spiritual Hot Mess Express Ltd | Arts & recreation | 2026 |
| Spitfire Heating Ltd | Construction | 2019 |
| SPN Corporate Displays Ltd | Professional & scientific | 2018 |
| Spomb Fishing Limited | Wholesale & retail | 2013 |
| Spomb International Limited | Wholesale & retail | 2014 |
| Spomb Limited | Wholesale & retail | 2008 |
| Sports Media International Limited | Professional & scientific | 2001 |
| Spray'N'Cloth Ltd | Administrative & support | 2026 |
| Springate Barns (RMC) Ltd | Real estate | 2025 |
| Springhead Resident Management Company Limited | Households | 2016 |
| Springwood Court Limited | Construction | 2018 |
| Spritz Bar Italiano Ltd | Hospitality | 2024 |
| Sprizzato Ltd | Other services | 2011 |
| SPS Electrical Services Limited | Construction | 2016 |
| SPU Consultants Ltd | Professional & scientific | 2015 |