| Safe Haven Dementia Centre Limited | Health & social care | 2014 |
| Safe on Site Limited | Professional & scientific | 2020 |
| Safehaven Roofing Company Ltd | Construction | 2025 |
| Saffron Stone Investments Ltd | Real estate | 2019 |
| Saffron Stone Private Limited | Other services | 2017 |
| Sage Repair Solutions Ltd | Manufacturing | 2025 |
| SAI Adhish Limited | Administrative & support | 2022 |
| SAI Sharan Consultancy Limited | Professional & scientific | 2014 |
| SAI Sharan Investments Limited | Real estate | 2020 |
| Saibaba Solutions Limited | Wholesale & retail | 2022 |
| Sailaboat Limited | Information & communication | 2009 |
| SAK Primehome Management Ltd | Real estate | 2026 |
| Salsac Limited | Administrative & support | 2021 |
| SAM Warren Ltd | Administrative & support | 2024 |
| Samagra Developments Ltd | Construction | 2026 |
| Samot Construction Co Ltd | Construction | 2020 |
| Samy Express Ltd | Hospitality | 2025 |
| Sandalston Limited | Real estate | 2024 |
| Sandkot Limited | Construction | 1984 |
| Sarah Skepper Ltd | Arts & recreation | 2024 |
| Sarock Ltd | Real estate | 2021 |
| Saronoma Limited | Financial services | 2013 |
| Satnam (UK) Ltd | Hospitality | 2012 |
| Savvy Managers Ltd | Professional & scientific | 2015 |
| SAX Roofing Ltd | Construction | 2003 |
| SB Amersham Limited | Hospitality | 2016 |
| SB Dental Ltd | Health & social care | 2012 |
| Scaffitalia Ltd | Manufacturing | 2022 |
| Scenic Retreats Ltd | Hospitality | 2026 |
| Science: Gamed Ltd | Information & communication | 2015 |
| Scientific Home USE Products Limited | Wholesale & retail | 2017 |
| Scmr Ltd | Information & communication | 2024 |
| Scuderia Select Limited | Information & communication | 2026 |
| Scuderiaselect Holdings Limited | Financial services | 2026 |
| SDA Reward Ltd | Administrative & support | 2017 |
| SDE (West Herts) LLP | | 2013 |
| SDE House (Amersham) Limited | Real estate | 2025 |
| Seasons Catering Company Limited | Hospitality | 2005 |
| Sebelle Holdings Ltd | Real estate | 2020 |
| Securon Holdings Limited | Financial services | 2017 |
| Securon Manufacturing Limited | Professional & scientific | 1947 |
| Securon Property Holdings Limited | Real estate | 2007 |
| Sehweni Enterprise Ltd | Wholesale & retail | 2015 |
| Selectstaff Recruitment Limited | Administrative & support | 2023 |
| Selene Enterprises Limited | Construction | 2014 |
| Selkie Hair Limited | Wholesale & retail | 2021 |
| Selling Savvy PVT Ltd | Wholesale & retail | 2025 |
| Sempare Limited | Administrative & support | 2018 |
| Service Support Solutions Ltd | Information & communication | 2025 |
| Seven Horses Limited | Construction | 2023 |
| Seventh Sense Theatre Ltd | Arts & recreation | 2019 |
| SG Eaton & Co Ltd | Professional & scientific | 2011 |
| Sg&Uk Properties Limited | Real estate | 2024 |
| SG80 Ltd | Information & communication | 2023 |
| Shake Content Ltd | Information & communication | 2014 |
| Shakya Consulting Ltd. | Information & communication | 2018 |
| Shalin Ltd | Other services | 2018 |
| Shapeimage Limited | Financial services | 1999 |
| Shardeloes Farm Limited | Administrative & support | 1999 |
| Sharp Sell Productions London Limited | Arts & recreation | 1996 |
| Shayko Limited | Real estate | 2015 |
| Shazrin Consulting Limited | Professional & scientific | 2021 |
| Shazrin Estates Limited | Real estate | 2020 |
| Shearer Developments Limited | Professional & scientific | 1995 |
| Shearer Estates Limited | Extraterritorial | 1995 |
| Shearer Property Associates Limited | Professional & scientific | 2007 |
| Shearer Property Brooklands Ltd | Professional & scientific | 2016 |
| Shearer Property C Limited | Real estate | 2014 |
| Shearer Property Developments Limited | Professional & scientific | 1997 |
| Shearer Property Group Limited | Professional & scientific | 1996 |
| Shearer Property Holdings Limited | Professional & scientific | 1995 |
| Shearer Property Investments a Limited | Real estate | 1996 |
| Shearer Property Investments B Limited | Extraterritorial | 1996 |
| Shearer Property L Ltd | Real estate | 2016 |
| Shearer Property LLP | | 2007 |
| Shearer Property O Ltd | Professional & scientific | 2016 |
| Shearer Property Partners Ltd | Real estate | 2018 |
| Shearer Property X Ltd | Construction | 2016 |
| Shelf Help Ltd | Professional & scientific | 2026 |
| Shemmings Consultancy Limited | Professional & scientific | 2018 |
| Shihan Contracts Services Limited | Administrative & support | 2005 |
| Shining Life Children's Trust | Health & social care | 1997 |
| Shiona Limited | Other services | 2019 |
| Ship Shape Cleaning (London) Ltd | Administrative & support | 2021 |
| Shirdisai Innovations Limited | Real estate | 2015 |
| Shofiz Limited | Wholesale & retail | 2021 |
| Shri Condiments Ltd | Wholesale & retail | 2022 |
| Shwan Data Solutions Ltd | Information & communication | 2019 |
| Shyam Homes Ltd | Real estate | 2020 |
| Sidetip Limited | Financial services | 2000 |
| Sidney Santiago Ltd | Arts & recreation | 2024 |
| Sieg Consultancy Ltd | Information & communication | 2008 |
| Sieger Systems Limited | Manufacturing | 2007 |
| Sierra Software Solutions Limited | Information & communication | 2023 |
| Signeyes Limited | Other services | 2014 |
| Signx Limited | Manufacturing | 2014 |
| Silent Disco 4 Hire Limited | Arts & recreation | 2026 |
| Silk Touch Laser Ltd | Administrative & support | 2017 |
| Silva Legal Services Limited | Professional & scientific | 2013 |
| Silver Editions Limited | Wholesale & retail | 1997 |