| Stability Ltd | Information & communication | 2002 |
| Stable Close Wexham Limited | Households | 2026 |
| Stable Events Ltd | Administrative & support | 2021 |
| Stable Media Group Ltd | Administrative & support | 2022 |
| Stable Rise Limited | Professional & scientific | 2016 |
| Stable Rise Property Holdings Limited | Households | 2019 |
| Stag Leisure Ltd | Hospitality | 2018 |
| Stan Social Agncy Ltd | Professional & scientific | 2022 |
| Stand Investment Group Limited | Financial services | 2017 |
| Standon Place Management Limited | Households | 2007 |
| Standon Solutions Limited | Administrative & support | 2022 |
| Starflare LLP | | 2025 |
| Starlike Universe Ltd | Information & communication | 2021 |
| Starpark Solutions Limited | Construction | 2011 |
| Starspice Ingredients Limited | Wholesale & retail | 2008 |
| Start Right Montessori Limited | Education | 2017 |
| Station Gate Management Company Limited | Households | 2018 |
| Statistix Marketing Limited | Other services | 2022 |
| Staz Consulting Limited | Administrative & support | 2021 |
| Steel Veteran Sentinels Limited | Administrative & support | 2024 |
| Stelios Real Estate Ltd | Real estate | 2024 |
| Step by Step Fitness Limited | Arts & recreation | 2023 |
| Stephen Austin & Sons Limited | Manufacturing | 2002 |
| Stephen Austin (Holdings) Limited | Financial services | 2001 |
| Stephen Gallagher Surveyors Limited | Professional & scientific | 2021 |
| Sterling Marketing Group LLP | | 2025 |
| Steve Baldwin Photography Limited | Professional & scientific | 2015 |
| Steve Burges Investments Limited | Professional & scientific | 2025 |
| Steve Coleman (Timber Erectors) Limited | Construction | 2007 |
| Steve Gant Consulting Ltd | Professional & scientific | 2020 |
| Steven Oates Limited | Real estate | 2004 |
| Steven Oates Property Management Limited | Administrative & support | 2015 |
| Stevenson Engineering Research Limited | Professional & scientific | 1999 |
| Stewarts Auto Solutions Limited | Wholesale & retail | 2021 |
| Stewarts Tail-Lift Limited | Wholesale & retail | 1998 |
| STG Herts Limited | Financial services | 2023 |
| Sticky Crayons Limited | Construction | 2019 |
| Still Scaffolding Limited | Construction | 2010 |
| Still Tanning Ltd | Other services | 2024 |
| Stoneblue Durham Limited | Real estate | 2020 |
| Stonyhills Property Management Limited | Real estate | 2020 |
| Storage Equipment Experts Limited | Professional & scientific | 2014 |
| Stormx Recruitment Limited | Administrative & support | 2017 |
| Stortford Kitchens Limited | Wholesale & retail | 2016 |
| Stow Sparks Co Ltd | Construction | 2025 |
| Strategically Tactically Limited | Information & communication | 2014 |
| Strawhors Limited | Manufacturing | 2018 |
| Streamline Your Print Limited | Manufacturing | 2012 |
| Stroie Limited | Transport & logistics | 2022 |
| Strom Vision Express (UK) Ltd | Wholesale & retail | 2026 |
| Strongbox Computers Ltd | Manufacturing | 2015 |
| Stuart & Denise Ross Limited | Professional & scientific | 2008 |
| Stuart Burford Trading Limited | Professional & scientific | 2025 |
| Studio 116 Training Limited | Administrative & support | 2018 |
| Studio C Architects Limited | Professional & scientific | 2010 |
| Studio Cornell Ltd | Arts & recreation | 2018 |
| Studio Displays Limited | Administrative & support | 2025 |
| Studio Joma Ltd | Professional & scientific | 2020 |
| Studio Moya Interiors Limited | Real estate | 2025 |
| Studio on Limited | Professional & scientific | 2025 |
| Studio One Projects Limited | Construction | 2011 |
| STX-A10 Limited | Construction | 2017 |
| Sublime AV & Security Limited | Information & communication | 2005 |
| Suite Properties and Loans Ltd | Professional & scientific | 2013 |
| Summerhill Court Association (ST. Albans) Limited | Households | 1988 |
| Summit Construction (Herts) Ltd | Construction | 2025 |
| Sun Street Creative Ltd | Arts & recreation | 2011 |
| Sunflower Management Services Limited | Professional & scientific | 2023 |
| Sunningdale Mews Management Company Limited | Households | 1991 |
| Sunsets and Marshmallows Limited | Hospitality | 2018 |
| Supreme Athletics Ltd | Arts & recreation | 2026 |
| Supreme Self Storage Limited | Transport & logistics | 1995 |
| Surety Financial Planning Limited | Professional & scientific | 2010 |
| Surety Ltd | Information & communication | 2022 |
| Surrogacy Lawyers Limited | Professional & scientific | 2012 |
| Susa Roberts Bookkeeping Ltd | Professional & scientific | 2016 |
| Sustain Abilities Limited | Construction | 2013 |
| Svtw Holdings Ltd | Other services | 2025 |
| Swallow Court Management Company (Hertford) Limited | Households | 1985 |
| Swallow Management Company Limited | Households | 1995 |
| Sweeney Rodd's Ltd | Other services | 2024 |
| Sweeps Management Company Limited | Households | 2005 |
| Sweetcorn Limited | Information & communication | 2026 |
| Swift Biotech Consultancy Ltd | Professional & scientific | 2023 |
| Swift Irrigation Ltd | Administrative & support | 2024 |
| Swim Plus Ltd | Education | 2017 |
| Swim Plus Management Limited | Education | 2023 |
| Swiss Brand Partners (UK) Limited | Wholesale & retail | 2020 |
| Swiss Organic Solutions Limited | Wholesale & retail | 2014 |
| Symphony Court (Edgware) Management Company Limited | Households | 2003 |
| Sync Community UK Limited | Arts & recreation | 2022 |
| Syncratec Limited | Information & communication | 2024 |
| Synergy Music Limited | Wholesale & retail | 2005 |
| Synergy Service Solutions Limited | Professional & scientific | 2020 |
| T Development Group Limited | Real estate | 2026 |
| T Faulkner Consulting Limited | Extraterritorial | 2012 |
| T P Autos Ltd | Wholesale & retail | 2016 |
| T W Property Services Limited | Construction | 2004 |
| T. E. D. Business Solutions Limited | Administrative & support | 2023 |
| T.G.I.Buildings Ltd | Water & waste | 2018 |