| Scott Design Solutions Limited | Administrative & support | 2011 |
| Scoundrel Films Ltd | Information & communication | 2018 |
| Scout Digital Limited | Information & communication | 2014 |
| Scratch Made Ltd | Hospitality | 2018 |
| Screen Options Limited | Arts & recreation | 1999 |
| Screen Settings Ltd | Information & communication | 2021 |
| Sculptart Ltd | Arts & recreation | 2023 |
| SD Films Ltd | Arts & recreation | 2025 |
| SD SET Works Limited | Construction | 2013 |
| SD14 Limited | Other services | 2014 |
| Sdamji Investments Limited | Health & social care | 2025 |
| SDF FAS 1 Holdco Limited | Real estate | 2021 |
| SDR Estates Limited | Real estate | 2018 |
| SE CHL Ltd | Real estate | 2026 |
| SE Colney Heath Lane Ltd | Real estate | 2026 |
| Sea and Land Investments Limited | Real estate | 2024 |
| Sea Gypsy Limited | Wholesale & retail | 2016 |
| Seabridge Properties Limited | Real estate | 1995 |
| Seak Limited | Administrative & support | 2025 |
| Seal Entertainments Limited | Arts & recreation | 2012 |
| Sean Claudia Limited | Other services | 2016 |
| Search Capital Limited | Financial services | 2023 |
| Seat Loader Group Limited | Wholesale & retail | 2023 |
| Seat Loader Ltd | Wholesale & retail | 2023 |
| Secateur Ltd | Extraterritorial | 2020 |
| Secomak Manufacturing Limited | Manufacturing | 2018 |
| Sector Support Services Ltd | Administrative & support | 2020 |
| Secure A-Build Limited | Administrative & support | 2024 |
| Securestyle Windows Trade Limited | Construction | 2009 |
| Securitas Bidco Limited | Administrative & support | 2021 |
| Securitas Midco Limited | Administrative & support | 2021 |
| Securitas Topco Limited | Administrative & support | 2021 |
| Security & Alarms Ltd | Administrative & support | 2021 |
| Security Elite Limited | Administrative & support | 2020 |
| Security Software Solutions Ltd | Information & communication | 2010 |
| Sedanca Limited | Real estate | 2023 |
| Sedem Care Limited | Health & social care | 2013 |
| Sekura Mobile Intelligence Ltd | Information & communication | 2019 |
| SEL Constructions (AL) Ltd | Construction | 2014 |
| Sela Shalom Limited | Real estate | 2025 |
| Selaco Ltd | Professional & scientific | 2016 |
| Selamor Ltd | Hospitality | 2020 |
| SEN Saturdays Ltd | Health & social care | 2023 |
| Send Parents Help CIC | Information & communication | 2026 |
| Sendadventure Ltd | Public administration | 2025 |
| Sendit Express Limited | Transport & logistics | 2017 |
| Senior DEV Time Ltd | Professional & scientific | 2022 |
| Senior King Communications Group Limited | Professional & scientific | 1982 |
| Senior King Interactive Limited | Professional & scientific | 1998 |
| Senior King Limited | Professional & scientific | 1977 |
| Senior King Print & Design Limited | Professional & scientific | 1999 |
| Senior King Solutions Limited | Professional & scientific | 1991 |
| Sennet & Meyers Limited | Wholesale & retail | 2025 |
| Sense AM Ltd | Information & communication | 2024 |
| Sensify (UK) Limited | Information & communication | 2014 |
| Sensify Solutions Limited | Information & communication | 2014 |
| Sentinel Management Limited | Real estate | 2019 |
| Sepaad Limited | Other services | 2012 |
| Sepeo Ltd | Health & social care | 2024 |
| Serene Stays London Ltd | Real estate | 2026 |
| Sergios (London) Limited | Hospitality | 2006 |
| Servas Court Management Limited | Households | 2013 |
| Serveaiq Limited | Information & communication | 2025 |
| SET Action Hire Ltd | Transport & logistics | 2022 |
| SET Colours Limited | Information & communication | 2014 |
| Settlers (2NK) Ltd | Real estate | 2024 |
| Seven Graphics Limited | Manufacturing | 2018 |
| Seven Singer Productions Limited | Information & communication | 2017 |
| Seventeen Grosvenor Square Limited | Households | 1960 |
| Seventy Nine Camden Limited | Real estate | 2023 |
| Sexual Health in Practice Community Interest Company | Education | 2017 |
| Seymour and Otto Ltd | Arts & recreation | 2019 |
| Seymours Estate Agents Limited | Real estate | 2007 |
| SF Furlong Roofing & Building Maintenance Ltd | Construction | 2020 |
| SF Group Holdings Limited | Professional & scientific | 2025 |
| SF Investment Properties Limited | Real estate | 2017 |
| SF Stefan Civil Engineering and Utility Contractors Ltd | Construction | 2009 |
| SFR Construction Limited | Other services | 2010 |
| Sfzi Ltd | Wholesale & retail | 2023 |
| SG GAS Services Ltd | Construction | 2020 |
| SG Propco Limited | Extraterritorial | 2022 |
| SG UK Events Limited | Arts & recreation | 2015 |
| SGN Healthcare Limited | Health & social care | 2013 |
| Sgsl Holding Limited | Financial services | 2024 |
| Sgsl Limited | Health & social care | 2008 |
| SH Business Consultancy LLP | | 2018 |
| SH Healthcare Management Ltd | Professional & scientific | 2023 |
| Shaare Zedek UK | Health & social care | 2010 |
| Shadow Artist Ltd | Information & communication | 2024 |
| Shadrac Consulting Ltd | Other services | 2018 |
| Shake Station Ltd | Wholesale & retail | 2026 |
| Shaktipeeth Digital Ltd | Manufacturing | 2022 |
| Shalimar Estates Ltd | Real estate | 2017 |
| Shamena Food Ltd | Hospitality | 2018 |
| Shandel Fashion Accessories Limited | Wholesale & retail | 2002 |
| Shannon Childcare Limited | Real estate | 2013 |
| Shannon Construction Training Ltd | Construction | 2024 |
| Shannon Investments Ltd | Real estate | 2022 |
| Shannon Site Services Limited | Construction | 2017 |
| Shannon Survey Limited | Administrative & support | 2010 |