| Sasuni Incorporated Limited | Professional & scientific | 1998 |
| Sat-Elite Limited | Manufacturing | 1995 |
| SAT. Comms. Limited | Manufacturing | 2005 |
| Satellite Recovery 24/7 Limited | Transport & logistics | 2023 |
| Savalan Construction Ltd | Construction | 2018 |
| Savvy Design Limited | Professional & scientific | 2005 |
| Saxon Coast Consultants Ltd | Professional & scientific | 2005 |
| Saxon Coast Services Ltd | Financial services | 2000 |
| Saxon Lodge Care Limited | Administrative & support | 2007 |
| Saxon Lodge Residential Home Limited | Health & social care | 1999 |
| SB Physio Limited | Health & social care | 2016 |
| SBM Engineering Limited | Administrative & support | 2005 |
| Sbrcom Ltd | Professional & scientific | 2014 |
| SC Johnson Ltd | Manufacturing | 2001 |
| Scanning Solutions Ltd | Professional & scientific | 2002 |
| SCB Computing (UK) Limited | Information & communication | 2004 |
| Scene Seven Film Services Ltd | Administrative & support | 1999 |
| Schiffer Europe Limited | Wholesale & retail | 1985 |
| Scholars Place (Iwade) Management Company Limited | Households | 2025 |
| Scholastic Life & Times Limited | Administrative & support | 2006 |
| School Life & Times Limited | Administrative & support | 2004 |
| Schools Newspaper Group Limited | Professional & scientific | 1986 |
| SCJ Eurafne Ltd | Administrative & support | 2001 |
| Scorewise Limited | Professional & scientific | 1988 |
| Scriptrose Limited | Real estate | 1981 |
| Scruttons Security Group Limited | Professional & scientific | 1965 |
| SDC Reprographics Limited | Manufacturing | 2002 |
| Sdsh Services Ltd | Administrative & support | 2021 |
| Sea Lipscombe Communications Limited | Professional & scientific | 2001 |
| Seamaxclean Limited | Other services | 2006 |
| Searchkeen Limited | | 1992 |
| Seaton House School Limited | Education | 1987 |
| Seaworld Services Limited | Information & communication | 2005 |
| Sebastian & Co Builders Ltd | Construction | 2006 |
| SEC Estates Limited | Real estate | 2007 |
| Second Life Longevity Ltd | Health & social care | 2026 |
| Secure Technical Solutions Limited | Manufacturing | 2007 |
| Secureside Residents Management Limited | Households | 1992 |
| Security FX Limited | Professional & scientific | 2003 |
| Securitytec Limited | Wholesale & retail | 2005 |
| Seddon Stores Limited | Wholesale & retail | 2023 |
| SEE Hear (2002) Limited | Information & communication | 2002 |
| Seed Surf Company Limited | Administrative & support | 2006 |
| Seedfit Limited | Wholesale & retail | 2025 |
| SEI Properties Limited | Households | 2007 |
| Selin Consultancy Limited | Professional & scientific | 2017 |
| Seline Properties Limited | Real estate | 1993 |
| Selvo Properties Ltd | Real estate | 2024 |
| Sendhurst Property Management Limited | Real estate | 2006 |
| Senior Serenity Healthcare Ltd | Public administration | 2023 |
| Sentastic Tutors Ltd | Education | 2021 |
| Senthu Ltd | Wholesale & retail | 2025 |
| Senyah Consulting Ltd | Professional & scientific | 2005 |
| SEO ANT Ltd | Professional & scientific | 2019 |
| SEP Heights Ltd | Real estate | 2023 |
| Serendata Ltd | Information & communication | 2026 |
| Serenity School Coulsdon Limited | Education | 2018 |
| Serpentine Developments Limited | Construction | 2005 |
| SES Business Water Limited | Water & waste | 2016 |
| Sesw Holding Company Limited. | Financial services | 2001 |
| Seventeen Management Limited | Real estate | 2004 |
| Seyoni Limited | Administrative & support | 2020 |
| SG Homes Limited | Construction | 2003 |
| SG Sports Coaching Limited | Education | 2007 |
| SGR Solar Ltd | Construction | 2025 |
| Shabizar Properties Limited | Real estate | 2007 |
| Shah Construction Limited | Construction | 2004 |
| Shakti Publishing Ltd | Information & communication | 2021 |
| Shamini Limited | Real estate | 2018 |
| Shamu&Narro Ltd | Real estate | 2024 |
| Shan Pharmacy Limited | Wholesale & retail | 1995 |
| Shan Tana & Co Ltd | Professional & scientific | 2007 |
| Shape London Architects Ltd | Construction | 2017 |
| Shaq Trading Limited | Wholesale & retail | 2024 |
| Sharif Sons Ltd | Real estate | 2018 |
| Shariscom Limited | Information & communication | 1998 |
| Sharkish Business Services Ltd | Professional & scientific | 2025 |
| Sharma + Sharma Properties Ltd | Real estate | 2003 |
| Sharper Homes Limited | Construction | 2006 |
| Sharris RAM Limited | Professional & scientific | 2005 |
| Shartimes Limited | Households | 1986 |
| Shaw's Electrical Limited | Construction | 1982 |
| Shawma Construction Services Limited | Construction | 2006 |
| Shawstart Learning Consultancy Ltd | Professional & scientific | 2006 |
| Shaymead Limited | Real estate | 2000 |
| Shayona Builders Limited | Construction | 2013 |
| Sheen Designs Limited | Wholesale & retail | 2003 |
| Sheen Kitchens Ltd | Real estate | 1992 |
| Shelian Contracts Limited | Professional & scientific | 1978 |
| Shell (Plastering) Limited | | 1973 |
| Shellpoint Trustees (Investments) Limited | Real estate | 1997 |
| Shepperton Developments Limited | Construction | 2006 |
| Sheridan Brooks Limited | Professional & scientific | 1995 |
| Sherlock and Neal Limited | Construction | 1976 |
| Sherrington, Ellis & Terry Limited | Arts & recreation | 1972 |
| Sherwood Interiors Limited | Construction | 1989 |
| Sherwoods Consultants Limited | Real estate | 1997 |
| Shield Thermal Insulation Limited | Construction | 2003 |
| Shieldasset Properties Limited | Real estate | 2023 |
| Shine IT Ltd | Information & communication | 2018 |