| Scaleup Partners Limited | Professional & scientific | 2021 |
| Scarson Computing Limited | Information & communication | 2012 |
| Schermo LED Ltd | Information & communication | 2020 |
| Schindele Maintenance Ltd | Real estate | 2024 |
| Schools Management Support Ltd | Professional & scientific | 2016 |
| Scorpion Professional Pathways Ltd | Administrative & support | 2025 |
| Scott Robbins Consulting Ltd | Professional & scientific | 2020 |
| Sculpt Studio Sevenoaks Limited | Other services | 2026 |
| SDS Housing Ltd | Financial services | 2024 |
| SE Metal Fabrications Ltd | Manufacturing | 2021 |
| Sea Sky House Management Limited | Households | 2021 |
| Seaton Property Management Limited | Real estate | 2016 |
| Security INS Broking Limited | Financial services | 2018 |
| Sedulity Consulting Ltd | Professional & scientific | 2024 |
| Seekout Holdings Ltd | Arts & recreation | 2022 |
| SEF Hands Limited | Construction | 2025 |
| Selber Records Limited | Arts & recreation | 2022 |
| Select Equipment (London) Limited | Wholesale & retail | 1970 |
| Self-Care and Health Education Ltd | Education | 2018 |
| Selida Consulting Limited | Professional & scientific | 2020 |
| Sellman Conservation Ltd | Construction | 2025 |
| Seta London Ltd | Wholesale & retail | 2024 |
| Severn Bridging Ltd | Financial services | 2015 |
| Sewbizz Limited | Manufacturing | 2014 |
| Seymour Distillery Ltd | Manufacturing | 2023 |
| SF Cooper Ltd | Professional & scientific | 2025 |
| SG Path Limited | Health & social care | 2016 |
| SG Works Ltd | Health & social care | 2024 |
| SGM Accountants Limited | Professional & scientific | 2022 |
| SH London Limited | Other services | 2025 |
| Shampooches Ltd | Other services | 2022 |
| Sharper Practice Ltd | Professional & scientific | 2011 |
| Shaw Associates Limited | Professional & scientific | 1987 |
| Shearman Properties Ltd | Real estate | 2023 |
| Shebah Nazir Ltd | Administrative & support | 2016 |
| Sheltirx (UK) Ltd | Wholesale & retail | 2023 |
| Sheltirx Group Ltd | Professional & scientific | 2024 |
| Sheridan's Home Improvements Ltd | Other services | 2023 |
| Sherpet Installations Limited | | 1984 |
| Shields Premises Personnel Ltd | Other services | 2011 |
| Shires Partnership Limited | Financial services | 2006 |
| Shivshakti Property Ltd | Real estate | 2025 |
| Shola Fashola Ltd | Other services | 2018 |
| Shopod Ltd | Wholesale & retail | 2021 |
| Shortfilms.London Limited | Arts & recreation | 2019 |
| SHP Enterprises Limited | Professional & scientific | 2019 |
| Sidhu Ventures Ltd | Real estate | 2018 |
| Signage Media UK Ltd | Professional & scientific | 2018 |
| Signature Dental Ltd | Health & social care | 2007 |
| Silk & Steel Ltd | Health & social care | 2015 |
| Silver Blue Services Ltd | Other services | 2018 |
| Silverbox Solutions Ltd | Information & communication | 2012 |
| Silvermere RTM Company Limited | Real estate | 2014 |
| Silverpoint Limited | Professional & scientific | 2020 |
| Simha Ltd | Information & communication | 2014 |
| Simon Kielty Electrical Ltd | Construction | 2006 |
| Simon Morris Associates Limited | Professional & scientific | 2003 |
| Simplicity Services London Limited | Administrative & support | 2014 |
| Simply FUN Childcare Ltd | Education | 2024 |
| Sinic Propco Ltd | Real estate | 2026 |
| SIO Properties Limited | Real estate | 2022 |
| Sister & Co Estates Ltd | Hospitality | 2026 |
| Sister Estates Ltd | Real estate | 2026 |
| SJ Assets & Finance Ltd | Financial services | 2022 |
| SJD Construction Solutions Ltd | Professional & scientific | 2024 |
| SJL Electrical Contractors Limited | Manufacturing | 2009 |
| SJT Consulting Group Ltd | Information & communication | 2020 |
| Skarch Limited | Administrative & support | 2017 |
| SKD Tyre Ltd | Wholesale & retail | 2019 |
| Skope Medical Limited | Health & social care | 2011 |
| SKP Accountancy Services Ltd | Professional & scientific | 2009 |
| SKP Building Contractors Ltd | Construction | 2023 |
| Skymmers Limited | Professional & scientific | 2018 |
| Slade Ventures Ltd | Financial services | 2018 |
| SLC Homes (UK) Limited | Real estate | 2020 |
| SLC Management (UK) Limited | Real estate | 2011 |
| Sleep Apnea Clinic Limited | Real estate | 2014 |
| Sleeptwitch Limited | Information & communication | 2011 |
| SLF Car Sales Ltd | Wholesale & retail | 2018 |
| SM Art Advisory Ltd | Arts & recreation | 2025 |
| SM2.A Holdings Limited | Real estate | 2023 |
| Small Press Music Ltd | Information & communication | 2012 |
| Smile 4 Kids Ltd | Other services | 2018 |
| Smile 4 U Limited | Health & social care | 2003 |
| Smile 4 U Shirley Limited | Health & social care | 2017 |
| SMJ Brands Ltd | Wholesale & retail | 2019 |
| Snake Skills Ltd | Real estate | 2018 |
| SNK Properties Ltd | Real estate | 2011 |
| Socs Gokson Capital Limited | Information & communication | 2011 |
| Sofia Thomas Ltd | Professional & scientific | 2017 |
| Sogo Properties Ltd | Real estate | 2026 |
| Solar Serve South East Ltd | Construction | 2022 |
| Solerox Holdings Limited | Real estate | 2017 |
| Solvance Consulting Ltd | Professional & scientific | 2025 |
| Sone CD Ltd | Information & communication | 2017 |
| Sophman Solutions Ltd | Information & communication | 2013 |
| Sospropinvest Ltd | Real estate | 2025 |
| Sourced Time Ltd | Wholesale & retail | 2022 |
| Sourcex Ltd | Wholesale & retail | 2022 |
| South East Advisory Ltd | Professional & scientific | 2026 |