| Streamline Hospitality Limited | Hospitality | 2016 |
| Streatham Clinic Limited | Health & social care | 2008 |
| Streatham Management Company Limited | Households | 2013 |
| Streatham Manor Gardens Limited | Households | 1907 |
| Street Caffe Abbey Park Ltd | Hospitality | 2018 |
| Streeter Marshall LLP | | 2017 |
| Streets Ahead Estate Agents LLP | | 2009 |
| Streets Ahead Financial Consultants Limited | Financial services | 1994 |
| Streets Ahead Real Estate Group Limited | Real estate | 2003 |
| Streetwise Couriers Same Day Ltd | Transport & logistics | 2026 |
| Streetwise Holdings Limited | Financial services | 2024 |
| Strega Deli Ltd | Hospitality | 2026 |
| Stretton Green Management Company Limited | Households | 2013 |
| Strictly Roots Ltd | Wholesale & retail | 2025 |
| Strictly Vintage Ltd | Wholesale & retail | 2014 |
| Stride Group IO Ltd | Information & communication | 2025 |
| Strikemeapose Ltd | Professional & scientific | 2022 |
| Strikepro Security Services Limited | Administrative & support | 2025 |
| Strings on Fire Records Ltd | Information & communication | 2017 |
| Strong Group Holdings UK Limited | Financial services | 2019 |
| Strong Recruitment Group Limited | Administrative & support | 2011 |
| Strong Tower Consulting Ltd | Professional & scientific | 2007 |
| Strong Tower Property Ground Rent Ltd | Real estate | 2019 |
| Stroud House (Hook) M.C. Limited | Households | 2017 |
| Stroyco UK Limited | Construction | 2025 |
| STS Property Ltd | Real estate | 2021 |
| Stucco Studio London Ltd | Construction | 2024 |
| Student Success Formula Ltd | Education | 2015 |
| Students Achieve Ltd | Education | 2014 |
| Studio 357 Ltd | Professional & scientific | 2012 |
| Studio 55 Group Limited | Information & communication | 2025 |
| Studio B01 Limited | Information & communication | 2022 |
| Studio DPA Ltd | Other services | 2018 |
| Studio JKL Ltd | Professional & scientific | 2021 |
| Studio Kaape Ltd | Professional & scientific | 2021 |
| Studio KRU Ltd | Arts & recreation | 2026 |
| Studio Perfect Limited | Other services | 2017 |
| Studio Petak Ltd | Construction | 2018 |
| Studio Scarlet Ltd | Professional & scientific | 2018 |
| Studio Upstairs | Wholesale & retail | 1996 |
| Studio Weller Limited | Professional & scientific | 2026 |
| Studioserve.Uk Limited | Information & communication | 2008 |
| Study Abroad Consultants Ltd | Professional & scientific | 2018 |
| Study Hacks Limited | Education | 2019 |
| Study Skills Limited | Wholesale & retail | 2011 |
| STUDY2WORLD Ltd | Education | 2019 |
| Stump Zone Limited | Administrative & support | 2024 |
| STY Croydon Ltd | Hospitality | 2019 |
| Style Aura Limited | Wholesale & retail | 2026 |
| Style Events Decor Limited | Hospitality | 2020 |
| Stylecard Ltd | Administrative & support | 2025 |
| Styled by AMA Hair Salon Ltd | Other services | 2024 |
| Styledbyhabi Ltd | Wholesale & retail | 2025 |
| Stylelement Limited | Other services | 2012 |
| Stylezy Ltd | Information & communication | 2026 |
| Stylish Interiors Ltd | Construction | 2017 |
| Suban Cleaning Service Ltd | Administrative & support | 2025 |
| Subh Laabh Limited | Administrative & support | 2025 |
| Subhashini Properties Ltd | Real estate | 2024 |
| Subject: Education Limited | Education | 2014 |
| Subrot Healthcare Services Ltd | Health & social care | 2015 |
| Subs & Sweets Ltd | Hospitality | 2025 |
| Sucafina UK Ltd | Wholesale & retail | 1929 |
| Succeessify Limited | Information & communication | 2025 |
| Success and Growths Ltd | Wholesale & retail | 2025 |
| Successful Young People Ltd | Arts & recreation | 2022 |
| Sucofocus Limited | Information & communication | 2003 |
| SUD Italia 10 Limited | Hospitality | 2018 |
| Sudeco International Limited | Manufacturing | 1985 |
| Suds Laundrette Ltd | Other services | 2025 |
| SUE Shop Limited | Wholesale & retail | 2012 |
| Sueta's Restland Africa Ltd | Health & social care | 2024 |
| Suffi Travel Ltd | Administrative & support | 2025 |
| Sufi Travel and Tour Worldwide Ltd | Information & communication | 2025 |
| Sugan Ltd | Construction | 2025 |
| Sugaplum Limited | Wholesale & retail | 2021 |
| Suite Home Estates Limited | Real estate | 2025 |
| Sulfonyl Limited | Households | 2004 |
| Suli Asset Management Ltd | Professional & scientific | 2024 |
| Sully Bands Limited | Information & communication | 2023 |
| Sulzdorf Company Ltd | Health & social care | 2025 |
| Suma Digital Limited | Professional & scientific | 2025 |
| Suma Properties Ltd | Real estate | 2019 |
| Sumglory Ltd | Wholesale & retail | 2023 |
| Summerfields (Farnworth) Management Company Limited | Households | 2004 |
| Summerview Court Flat Management Limited | Households | 2003 |
| Summerville Court (Croydon) Management Company Limited | Households | 1980 |
| Summerwood (Sunningdale) Management Company Limited | Households | 2012 |
| Summit Capital Developments Ltd | Real estate | 2025 |
| Summit Elevators Installations Ltd | Manufacturing | 2010 |
| Summit Elevators Limited | Manufacturing | 1997 |
| Summit Elevators Repairs Ltd | Manufacturing | 2018 |
| Summit Landscaping Co Limited | Administrative & support | 2025 |
| Sums House Management Limited | Households | 1986 |
| Sun Collaboration Ltd | Arts & recreation | 2022 |
| Sun Island Tanning Ltd | Other services | 2023 |
| Sun Life Cruise Travels Ltd | Administrative & support | 2025 |
| Sun Power Limited | Other services | 2018 |
| Sun Properties Management Ltd | Real estate | 2026 |
| Sun Recruitment Agency Ltd | Administrative & support | 2018 |