| Smith Homes 1 Consultancy Limited | Professional & scientific | 2017 |
| Smith Homes 1 Limited | Construction | 2014 |
| Smith Homes 10 Limited | Construction | 2016 |
| Smith Homes 11 Limited | Construction | 2016 |
| Smith Homes 12 Limited | Construction | 2017 |
| Smith Homes 13 Limited | Real estate | 2019 |
| Smith Homes 14 Limited | Real estate | 2020 |
| Smith Homes 2 Limited | Construction | 2014 |
| Smith Homes 3 Limited | Construction | 2015 |
| Smith Homes 4 Limited | Construction | 2015 |
| Smith Homes 5 Limited | Construction | 2015 |
| Smith Homes 6 Limited | Construction | 2015 |
| Smith Homes 7 Limited | Construction | 2015 |
| Smith Homes 9 Limited | Construction | 2016 |
| Smith Homes Construction 1 Limited | Construction | 2018 |
| Smith Homes Construction 3 Limited | Construction | 2021 |
| Smith Homes Construction Ltd | Construction | 2014 |
| Smith Homes Consultancy Limited | Professional & scientific | 2017 |
| Smith Homes Ground Rent Ltd | Real estate | 2019 |
| Smith Homes Holdings Limited | Financial services | 2022 |
| Smith Homes Limited | Construction | 2013 |
| Smith Homes Plant Hire Limited | Administrative & support | 2021 |
| Smith Homes Rentals Limited | Real estate | 2022 |
| Smith Taylormade (Trade) Limited | Manufacturing | 2002 |
| Snkrehab Limited | Other services | 2024 |
| SNX Services Limited | Information & communication | 2015 |
| Soane Architects Limited | Construction | 2020 |
| SOC of Assoc Management Limited | Other services | 2023 |
| Social Strength Limited | Professional & scientific | 2026 |
| Soft Pebble Limited | Information & communication | 2020 |
| Solarplicity UK Holdings Limited | Energy | 2015 |
| Sole Bay Estates Limited | Real estate | 2018 |
| Solid Web Solutions Limited | Information & communication | 2020 |
| Soljol Consultants Limited | Professional & scientific | 2017 |
| Solomon Lettings Ltd | Real estate | 2025 |
| Solutionlaw Limited | Professional & scientific | 2014 |
| Somnia London Ltd | Wholesale & retail | 2024 |
| Soopa Toobs (Tyres) Limited | Wholesale & retail | 1983 |
| Sooty Chimney Ltd | Administrative & support | 2016 |
| Sophie Bowyer Hair Limited | Other services | 2022 |
| Sorelle Equity Limited | Financial services | 2026 |
| Sound Guidance Ltd | Professional & scientific | 2018 |
| Sound INSUL8ION Limited | Professional & scientific | 2004 |
| South East Eco Systems Limited | Construction | 2022 |
| South East Inspection Services Ltd | Professional & scientific | 2026 |
| Southwood Property Development Ltd | Real estate | 2020 |
| Southyboy Ltd | Professional & scientific | 2014 |
| Sovereign Alteration & Laundry Ltd | Other services | 2019 |
| Sovereign DRY Cleaners (Ware) Ltd | Other services | 2018 |
| Sovereign Financial Management (Berkhamsted) Limited | Professional & scientific | 2004 |
| SP Auto Performance Ltd | Wholesale & retail | 2024 |
| Space Services (Herts) Ltd | Education | 2023 |
| Sparkle Rain Limited | Information & communication | 2019 |
| Spds Care Limited | Health & social care | 2017 |
| Specialist Roofers Ltd | Construction | 2014 |
| Spence Holdings Ltd | Hospitality | 2017 |
| Spence's Plumbing & Mechanical Consultancy Ltd | Administrative & support | 2018 |
| SPK Eco Solutions Limited | Construction | 2025 |
| Springfield Lodge (Hertford) Management Limited | Households | 2001 |
| Springfit Installations Ltd | Construction | 2020 |
| Square the Circle Consultants Ltd | Professional & scientific | 2024 |
| Squee Holdings Limited | Financial services | 2023 |
| SRH Props Limited | Other services | 2014 |
| SRJ Vaughan Consultancy Services Limited | Professional & scientific | 2022 |
| SRU Estates Ltd | Real estate | 2022 |
| SSM Fabrication & Powder Coating Limited | Manufacturing | 2021 |
| SSS Coaching Ltd | Education | 2025 |
| SSS Education Group Ltd | Education | 2020 |
| SSS Leapfrog Ltd | Education | 2026 |
| Sstc Services Ltd | Construction | 2026 |
| ST Andrew Bespoke Ltd | Construction | 2019 |
| ST Andrew Holdings Ltd | Financial services | 2019 |
| ST Edmund's College | Education | 2016 |
| ST. Evroul Court Management Company Limited | Extraterritorial | 1986 |
| ST. Margaretsbury Management Co. Limited | Households | 1994 |
| ST. Ronans (Finchley) Management Limited | Households | 1993 |
| Stabilis Health and Fitness Limited | Other services | 2026 |
| Stag Eight Ltd | Real estate | 2019 |
| Stag Five Ltd | Real estate | 2019 |
| Stag Four Ltd | Real estate | 2019 |
| Stag Nine Ltd | Real estate | 2019 |
| Stag One Ltd | Real estate | 2019 |
| Stag Seven Ltd | Real estate | 2019 |
| Stag SIX Ltd | Real estate | 2019 |
| Stag TEN Ltd | Real estate | 2019 |
| Stag Three Ltd | Real estate | 2019 |
| Stag Two Ltd | Real estate | 2019 |
| Stairart Limited | Manufacturing | 2015 |
| Stan Homes Limited | Construction | 2005 |
| Standon Motor Cars Ltd | Wholesale & retail | 2026 |
| Stanley Hershey Limited | Real estate | 2017 |
| Stanstead Mill Day Nursery Limited | Health & social care | 2018 |
| Stansted Prestige Ltd | Wholesale & retail | 2008 |
| Stapleton Plant Hire Ltd | Wholesale & retail | 2018 |
| Stargard Ltd | Administrative & support | 2025 |
| Starz SFC Limited | Professional & scientific | 2019 |
| Steadfast Contracts Limited | Professional & scientific | 2012 |
| Steed Media Limited | Arts & recreation | 2024 |
| Steel Co Signs Ltd | Manufacturing | 2014 |
| Steelofitness Ltd | Health & social care | 2021 |