| Statera Strategy Limited | Administrative & support | 2016 |
| STATESOFMIND3 Ltd | Health & social care | 2021 |
| Station Tech Solutions Ltd | Wholesale & retail | 2017 |
| Station Terrace Flats Management Limited | Households | 2022 |
| Status Restaurant Ltd | Hospitality | 2026 |
| Stay Covered Financial Services Ltd | Administrative & support | 2016 |
| Steadfast Holdings Limited | Real estate | 1995 |
| Steadihobshot Ltd | Information & communication | 2025 |
| Steelpark Trading Limited | Wholesale & retail | 2010 |
| Stella Sheriff Ltd | Wholesale & retail | 2020 |
| Stellar Coaching & Consulting Ltd | Professional & scientific | 2015 |
| Stemai III LLP | | 2025 |
| Step by Step Electrical Ltd | Construction | 2023 |
| Step by Step Property Management Ltd | Real estate | 2025 |
| Stephanie Belton Photography Ltd | Professional & scientific | 2009 |
| Stephen Archer Architects LLP | | 2004 |
| Stephen Ashford Associates Limited | Professional & scientific | 2017 |
| Stephen Goalby Ltd | Professional & scientific | 2024 |
| Stephen Hoffman Consulting Ltd | Other services | 2017 |
| Stephen Hurley Consulting Ltd | Information & communication | 2010 |
| Stephen Raymond Investments Limited | Financial services | 2023 |
| Stephens DCL Ltd | Real estate | 2016 |
| Sterling Music Limited | Information & communication | 2026 |
| Sterling Silva Ltd | Information & communication | 2022 |
| Steve Corcoran Limited | Professional & scientific | 2011 |
| Steve Davis Holdings Limited | Arts & recreation | 1987 |
| Stewart Superior Europe Limited | Manufacturing | 1994 |
| STK Technology Limited | Information & communication | 2024 |
| STL Medical Consulting Ltd | Health & social care | 2024 |
| Stock Property Investments Ltd | Real estate | 2005 |
| Stoic Renovations Ltd | Construction | 2024 |
| Stoked Developments Limited | Real estate | 2004 |
| Stone Green Homes Limited | Construction | 2020 |
| Stonefield Consulting Ltd | Other services | 2021 |
| Stonegate Homes (Pixham) Limited | Construction | 2021 |
| Stonehart Developments Ltd | Construction | 2019 |
| Stonewood Construction & Property Services Limited | Construction | 2011 |
| Store IT Solutions Ltd | Information & communication | 2016 |
| Storedaq (UK) Limited | Information & communication | 2018 |
| Storhaven Financial Services Ltd. | Financial services | 2011 |
| Storksak Limited | Manufacturing | 2003 |
| Stormont School | Education | 1962 |
| Stormseal Upvc Window Co Ltd | Extraterritorial | 2006 |
| Storytime Ltd | Administrative & support | 2018 |
| Stovold Construction Service Ltd | Wholesale & retail | 2008 |
| Stowstone Limited | Construction | 2017 |
| STR UK Distribution Ltd | Administrative & support | 2023 |
| Straightline Group Limited | Wholesale & retail | 2017 |
| Strategic Intent Consulting Ltd | Other services | 2018 |
| Stratstone Projects Limited | Construction | 2015 |
| Stratton & Hesler Limited | Construction | 2000 |
| Stratum Counsel Limited | Wholesale & retail | 2025 |
| Stratus Systems Ltd | Information & communication | 2018 |
| Stravik SVK Limited | Wholesale & retail | 2025 |
| Straw House Ventures Limited | Real estate | 2017 |
| Strictly Consulting Ltd | Information & communication | 2020 |
| Striking Places Limited | Professional & scientific | 2015 |
| Stripe Interiors Ltd | Manufacturing | 2021 |
| Stroheim Capital Holding Limited | Financial services | 2015 |
| Stroma Limited | Administrative & support | 1998 |
| Strong Roots Forest School Ltd | Education | 2025 |
| Strum and Drum Limited | Wholesale & retail | 2005 |
| Stryders Solicitors Limited | Professional & scientific | 2010 |
| Stuart Place (ST Albans) Management Company Limited | Households | 2017 |
| Stuart Vernon Consulting Limited | Professional & scientific | 2020 |
| Studio 10 Salon Ltd | Other services | 2022 |
| Studio Elms Ltd | Professional & scientific | 2022 |
| Studio GOH Limited | Professional & scientific | 2024 |
| Studio Jake LAI Limited | Professional & scientific | 2021 |
| Studio K8 Limited | Administrative & support | 2023 |
| Studio Kamini Ltd | Professional & scientific | 2009 |
| Studio Liminal Ltd | Information & communication | 2025 |
| Studio Sargent Limited | Professional & scientific | 2016 |
| Studio Torr Limited | Professional & scientific | 2026 |
| Study Advice Limited | Education | 2013 |
| Stumpy Oak Projects Ltd | Administrative & support | 2019 |
| Styfinity Limited | Other services | 2024 |
| Style IT Beautiful Limited | Wholesale & retail | 2018 |
| Style-Eyes Limited | Manufacturing | 2010 |
| Stylesnap Ltd | Professional & scientific | 2025 |
| SUB5 Ltd | Arts & recreation | 2022 |
| Subasm Limited | Information & communication | 2022 |
| Subnetic Solutions Limited | Information & communication | 1999 |
| Subud Publications International | Information & communication | 1975 |
| Success on Ltd | Information & communication | 2019 |
| Such & Lowe Limited | Construction | 1986 |
| Summerbee Home Solutions Ltd | Construction | 2025 |
| Summit Accounting Limited | Professional & scientific | 2025 |
| Summit Gardening and Landscaping Ltd | Administrative & support | 2021 |
| Summit Health ST Albans Ltd | Health & social care | 2026 |
| Summit Pest Control Ltd | Administrative & support | 2020 |
| Summit Support Ltd. | Health & social care | 2019 |
| Sundale Residents Company Limited | Real estate | 2008 |
| Sundial Marketing Limited | Professional & scientific | 2012 |
| Sunfacer Productions Limited | Information & communication | 2015 |
| Sunflower Sorters Limited | Other services | 2024 |
| Sunlight Roofing and Building Ltd | Construction | 2025 |
| Sunnydayz Properties Limited | Real estate | 2024 |
| Sunrise Education Limited | Education | 2010 |
| Sunrise Immigration Limited | Professional & scientific | 2010 |