| Ssd-Help Limited | Professional & scientific | 1998 |
| Ssharan Properties Ltd | Real estate | 2020 |
| Ssrj Properties Ltd | Real estate | 2020 |
| SST Renewables Limited | Energy | 2014 |
| ST Catherine's Care Centre Limited | Health & social care | 2018 |
| ST Christopher's Residents Association Limited | Households | 1991 |
| ST Edward Homes Limited | Construction | 2006 |
| ST Edward Homes Number Three Limited | Extraterritorial | 2007 |
| ST James Homes Limited | Construction | 2000 |
| ST John Homes Limited | Extraterritorial | 2003 |
| ST Johns Nursing Home Limited | Health & social care | 1987 |
| ST Katharine Homes Limited | Extraterritorial | 2003 |
| ST Peters Gardens Residents Limited | Households | 2001 |
| ST Teresa's Enterprises Limited | Administrative & support | 1998 |
| ST. Andrews (Warren Road) Residents Company Limited | Real estate | 1989 |
| ST. Andrews Flats Limited | Households | 2004 |
| ST. Ann's Limited | Health & social care | 2003 |
| ST. George's Road (Mitcham) Management Company Limited | Households | 1995 |
| ST. James Mews RES. Assoc. (Weybridge) Limited | Households | 1993 |
| ST. Mary's Centre for Maths Ltd | Education | 2007 |
| ST. Mary's Properties (Brighton) Limited | Real estate | 1981 |
| ST. Paul's Tea Company Limited | Manufacturing | 1982 |
| Staines Glass (UK) Limited | Transport & logistics | 1977 |
| Stalker Property Ltd | Real estate | 2003 |
| Stamp Consultancy Ltd | Information & communication | 2022 |
| Stanley Court Management Company (Mitcham) Limited | Administrative & support | 2004 |
| Stanstead Corner Residents Association Limited | Real estate | 1989 |
| Stantaine Limited | Other services | 1965 |
| Stapeley Investments Ltd | Real estate | 1995 |
| Star Tuitions Limited | Education | 2005 |
| Stargazer Computing Limited | Information & communication | 2000 |
| Starlight Productions Limited | Information & communication | 1993 |
| Starnational Limited | Information & communication | 1987 |
| Startchance Property Management Limited | Households | 1991 |
| Startwrite Limited | Information & communication | 1997 |
| Station Court Management Limited | Professional & scientific | 1980 |
| Station Kebab House LDN Ltd | Hospitality | 2022 |
| Station Road Limited Partnership | | 1993 |
| Stay Wild Ltd | Administrative & support | 2017 |
| Staying at Home Care Ltd | Health & social care | 2025 |
| Stayton Construction Limited | | 1984 |
| Stealth Scaffolding Limited | Construction | 2023 |
| Steann Homes Limited | Professional & scientific | 1992 |
| Stearn Metal Work Limited | Manufacturing | 2006 |
| Steele Partnership Limited | Real estate | 2006 |
| Steg Developments Limited | Real estate | 2004 |
| Stegglos Properties Ltd | Real estate | 2007 |
| Stegold Limited | | 1981 |
| Stemar Signalling and HR Consultants Limited | Professional & scientific | 2006 |
| Stentaway Limited | Hospitality | 2006 |
| Stentor Music Company Limited | Wholesale & retail | 1962 |
| Stephen Mason Surveyors Limited | Professional & scientific | 2011 |
| Stephen Mcdonald Ltd | Construction | 2002 |
| Stephen Underwood & Company Limited | Real estate | 1989 |
| Sterling Elite Rentals Ltd | Administrative & support | 2026 |
| Steve Hughes Sports Physiotherapy Ltd | Other services | 2024 |
| STG Fabrications Ltd. | Manufacturing | 1991 |
| Stoa Investments Limited | Financial services | 2024 |
| Stochel Electrical Limited | Construction | 1999 |
| Stokecare Limited | Real estate | 1982 |
| Stonecot Homes Limited | Real estate | 1962 |
| Stonenet Limited | Households | 1989 |
| Stormplan Limited | Construction | 2007 |
| Stow Vehicle Movement Services Limited | Transport & logistics | 2004 |
| Straight Edge Fabrication Limited | Manufacturing | 2005 |
| Strategic Links LLP | | 2006 |
| Strawberries & Cream | | 2005 |
| Strawberries & Cream | | 2005 |
| Strawberriez & Cream | | 2005 |
| Streamshare Property Management Limited | Households | 1989 |
| Streatham and District Sports Club,Limited | Hospitality | 1920 |
| Street Repairs Inspection Ltd | Construction | 2001 |
| Strelitzia Network Limited | Professional & scientific | 2005 |
| Strictly Personnel Limited | Administrative & support | 2003 |
| Strictly Shirts Limited | Extraterritorial | 2004 |
| Strong Build Projects Ltd | Construction | 2026 |
| Strongbow Engineering Limited | Professional & scientific | 1991 |
| Strongboy Ltd. | Manufacturing | 1992 |
| Stroudweb.Com Limited | Information & communication | 2006 |
| Studio Alphonso Paszkowski Limited | Professional & scientific | 2007 |
| Studio Charlie Limited | Professional & scientific | 2007 |
| Studio DAR Limited | Professional & scientific | 2002 |
| Studio Seventy Seven Limited | Information & communication | 2025 |
| Study and Play America Soccer Ltd | Arts & recreation | 2023 |
| Stylist Music Limited | Arts & recreation | 1983 |
| Suasion Ltd | Wholesale & retail | 2006 |
| Subtime Ltd | Hospitality | 2003 |
| Sugar Crystals Ltd | Wholesale & retail | 2026 |
| Suhail Enterprises Ltd | Hospitality | 2007 |
| Sully Form Limited | Construction | 2003 |
| Sumtotal.Com Limited | Professional & scientific | 2004 |
| Sun DO (London) Ltd | Hospitality | 2011 |
| Sun Sound Limited | Wholesale & retail | 2006 |
| Sunflora Limited | Wholesale & retail | 2005 |
| Sunmit Homes Limited | Construction | 1999 |
| Sunnyside (Lightwater) Limited | Real estate | 2004 |
| SUNRISE43 Ltd | Hospitality | 2025 |
| Sunset Travel Limited | Administrative & support | 1981 |
| Sunsoft Ltd | Information & communication | 1995 |
| Super 8 Restaurants Limited | Hospitality | 2014 |