| Serene Faith Ltd | Wholesale & retail | 2021 |
| Service Developments Investments Limited | Real estate | 2008 |
| Seven Clean Seas UK Limited | Professional & scientific | 2024 |
| SG Venues Ltd | Administrative & support | 2019 |
| SGA Management Consultancy Ltd | Professional & scientific | 2021 |
| Shakain Ltd | Other services | 2010 |
| Shakespeare & George Limited | Administrative & support | 2004 |
| Shan LIU Design Limited | Professional & scientific | 2023 |
| Shanly Homes (Beaconsfield) Limited | Construction | 2002 |
| Shanly Homes (Leatherhead) Limited | Construction | 2002 |
| Shanly Homes (South East) Limited | Construction | 2021 |
| Shanly Homes (Staines) Limited | Extraterritorial | 1971 |
| Shanly Homes Construction Limited | Construction | 2001 |
| Shanly Homes Limited | Construction | 1993 |
| Shanly Residential Limited | Construction | 2000 |
| Sharose Limited | Real estate | 2014 |
| Shaw Developments Ltd | Real estate | 2020 |
| Sheetal Kalsi Limited | Information & communication | 2010 |
| Shepherd Invest Limited | Administrative & support | 2007 |
| Sherborne Solutions Limited | Professional & scientific | 2009 |
| Sherfos Limited | Professional & scientific | 2020 |
| Sherley Estate Management Company Limited | Households | 2014 |
| Sherwood Securities Limited | Financial services | 2021 |
| Sherwood Technology Ventures Limited | Information & communication | 2023 |
| Shihn & Company LLP | | 2025 |
| Shire House Properties Limited | Real estate | 1985 |
| Shirlo Limited | Real estate | 1958 |
| Shorestorm Limited | Hospitality | 2020 |
| Shousugiban Ltd | Manufacturing | 2018 |
| Show ME Technologies Ltd | Information & communication | 2026 |
| Shreeg Enterprise Ltd | Professional & scientific | 2015 |
| Shreya SAI Estates Limited | Real estate | 2020 |
| Sidak Estates Ltd | Real estate | 2025 |
| Sierra FX Limited | Financial services | 2023 |
| Signature of Hertford (Operations) Limited | Health & social care | 2013 |
| Signature of Reigate (Operations) Limited | Health & social care | 2014 |
| Signature Senior Lifestyle Developments Limited | Real estate | 2005 |
| Signature Senior Lifestyle Finance Limited | Real estate | 2005 |
| Signature Senior Lifestyle GP III LLP | | 2013 |
| Signature Senior Lifestyle GP IV LLP | | 2019 |
| Signature Senior Lifestyle Holdings Limited | Real estate | 2005 |
| Signature Senior Lifestyle Investment Management Limited | Financial services | 2008 |
| Signature Senior Lifestyle Investments III Ltd | Financial services | 2013 |
| Signature Senior Lifestyle Investments IV Limited | Financial services | 2019 |
| Signature Senior Lifestyle Investments V Limited | Financial services | 2019 |
| Signature Senior Lifestyle Limited | Professional & scientific | 2005 |
| Signature Senior Lifestyle Nominee III Ltd | Financial services | 2013 |
| Signature Senior Lifestyle Operations Ltd | Health & social care | 2009 |
| Silvey-Buckingham Properties Ltd | Real estate | 2008 |
| Simko Ventures Limited | Financial services | 2021 |
| Simon Green Consulting Limited | Information & communication | 2008 |
| Simon Wagner Photography Limited | Professional & scientific | 2007 |
| Siren Holdings International Limited | Financial services | 2020 |
| Sirial Limited | Real estate | 2018 |
| Siyan Group Limited | Arts & recreation | 2019 |
| Siyan Limited | Arts & recreation | 2001 |
| Siyaran Ltd | Financial services | 2019 |
| Sjcconsulting Ltd | Professional & scientific | 2025 |
| SK Properties Group Ltd | Real estate | 2021 |
| Skill SET Recruitment Ltd | Administrative & support | 2025 |
| Skin Glow Studio Ltd | Other services | 2025 |
| Skinners Strolls Limited | Other services | 2021 |
| Skotch Consulting Ltd | Professional & scientific | 2013 |
| SKS Estates Ltd | Real estate | 2026 |
| Skyinfinity Ltd | Administrative & support | 2026 |
| Skylight Capital Ltd | Construction | 2021 |
| Skylight Enterprise Ltd | Construction | 2021 |
| Skyrock Ventures Limited | Other services | 2023 |
| Skywet Global Ltd | Wholesale & retail | 2020 |
| Slab Tiles and Stone Limited | Wholesale & retail | 2013 |
| SLE Builder Ltd | Construction | 2026 |
| Smart Concepts Global Ltd | Professional & scientific | 2026 |
| Smash Pro Limited | Real estate | 2022 |
| SMD Property Management Limited | Real estate | 1995 |
| Smiths Holdings Limited | Financial services | 2015 |
| Smiths Nurseries Limited | Wholesale & retail | 1998 |
| Smudgoff Cleaning Services Limited | Administrative & support | 2011 |
| Snowdrop Stud Co. Limited | Agriculture & fishing | 1989 |
| Snuggy Buggy Limited | Extraterritorial | 2000 |
| SO BE IT UN Limited | Education | 2025 |
| SO What Solutions Ltd | Professional & scientific | 2015 |
| Social Studio and Co Group Limited | Professional & scientific | 2025 |
| Soil Nurture Limited | Agriculture & fishing | 2022 |
| SOL6 Limited | Information & communication | 2022 |
| Somerford Place Management Ltd | Households | 1996 |
| Sommelier CRU Limited | Other services | 2005 |
| Sophie Bertrand Ltd | Health & social care | 2025 |
| Sopro Partners Ltd | Real estate | 2025 |
| Sorbon Developments Limited | Extraterritorial | 2001 |
| Sorbon Estates Limited | Construction | 1973 |
| Sorbon Finance Limited | Financial services | 2015 |
| Sorbon Properties Limited | Real estate | 2015 |
| Sound Curation Records Limited | Information & communication | 2017 |
| Sound Masking Limited | Extraterritorial | 2004 |
| Soundspace Ltd | Construction | 2019 |
| Soundview Limited | Construction | 2020 |
| Source Communications Limited | Professional & scientific | 1989 |
| South Bucks Animal Health Partners Limited | Other services | 2023 |
| South Bucks Electrical Ltd | Construction | 2024 |
| South London Prison Service LLP | | 2015 |