| Souvenir Edition Ltd | Administrative & support | 2026 |
| Sovereign Procurement Limited | Real estate | 2017 |
| Sovereign Sewing Machines Limited | Wholesale & retail | 1976 |
| SP Strategy Limited | Transport & logistics | 2016 |
| Spall Aesthetic Clinic Ltd | Health & social care | 2013 |
| Spanners Mobile Mechanics Ltd | Wholesale & retail | 2013 |
| Spark Edge Ltd | Construction | 2023 |
| Sparklingdesign Ltd | Professional & scientific | 2020 |
| Sparrow Capital Investments Limited | Real estate | 2013 |
| Spartan Group Ltd | Financial services | 2023 |
| Spartan Realty Ltd | Real estate | 2024 |
| Sparton Capital Holdings Ltd | Financial services | 2024 |
| Spatar Building Ltd | Construction | 2026 |
| SPD Wholesale Supplies Limited | Manufacturing | 2019 |
| Speakerbus Group PLC | Professional & scientific | 1997 |
| Specialist 4 Finance Ltd | Financial services | 2021 |
| Spik 'N' Span Ltd | Administrative & support | 2025 |
| Spindle Capital Limited | Financial services | 2017 |
| Spirited Thinking Limited | Administrative & support | 2016 |
| SPP Services (Enfield) Limited | Health & social care | 2013 |
| Spring Engineering Limited | Real estate | 2007 |
| Spring Steps Limited | Wholesale & retail | 2011 |
| Springfield Supported Living Ltd | Health & social care | 2024 |
| SPRINTERS4U Ltd | Wholesale & retail | 2024 |
| Spur Petroleum (London) Ltd. | Wholesale & retail | 1978 |
| Squires Property Investments Ltd | Real estate | 2022 |
| SRB UK Properties Limited | Real estate | 2025 |
| Sree Software Solutions Ltd | Information & communication | 2016 |
| SRK Shah Limited | Information & communication | 2026 |
| SRK Trading and Consultancy Ltd | Construction | 2020 |
| SRY Investments Ltd | Financial services | 2024 |
| SS Shipping Ltd | Wholesale & retail | 2022 |
| SSA North Ltd | Construction | 2020 |
| SSG Living LLP | | 2019 |
| SSSF1 Limited | Financial services | 2025 |
| ST Edward's Gate Management Company Limited | Households | 2020 |
| ST Margaret Healthcare Services Ltd | Manufacturing | 2021 |
| ST Paul's Way CHP Management Limited | Real estate | 2016 |
| ST Paul's Way Residential Management Limited | Real estate | 2017 |
| St'Reggies Limited | Health & social care | 2025 |
| ST. Leonards Developments LLP | | 2014 |
| Stack & Move Ltd | Transport & logistics | 2025 |
| Staff Tree Recruitment Limited | Administrative & support | 2024 |
| Staines Turkuaz Limited | Real estate | 2025 |
| Standon Holdings Limited | Hospitality | 2016 |
| Stansted Facility Services Ltd | Administrative & support | 2025 |
| Star 2 Share Ltd | Extraterritorial | 2023 |
| Star Express London Ltd | Wholesale & retail | 2021 |
| Star Kebab Fish and Chips Ltd | Hospitality | 2019 |
| Star Property Services Ltd | Real estate | 2017 |
| Star Records Ltd | Information & communication | 2024 |
| Stardust Face Painting and Glitter Bar Limited | Wholesale & retail | 2022 |
| Stardust Hair Braiding Limited | Other services | 2022 |
| Stargate Impex Ltd | Wholesale & retail | 2024 |
| START2CARE CIC | Education | 2024 |
| Station Cars (Cheshunt) Ltd | Transport & logistics | 2003 |
| Steel PAN in Motion | Arts & recreation | 2014 |
| Steel Subby Ltd | Manufacturing | 2022 |
| Stef Plastering Ltd | Construction | 2024 |
| Stellar Property Assets Limited | Real estate | 2026 |
| Stellos Limited | Wholesale & retail | 2022 |
| Step by ME Limited | Arts & recreation | 2017 |
| Steph Clip Factory Ltd | Professional & scientific | 2026 |
| Sterling Fire Services Limited | Construction | 2021 |
| Sterling Investments London Ltd | Real estate | 2019 |
| Sterling Outreach Services Limited | Health & social care | 2004 |
| Sterling Resourcing Ltd | Administrative & support | 2023 |
| Steve Anthony Ltd | Wholesale & retail | 2026 |
| Steve Emblen Holdings Limited | Financial services | 2026 |
| Stevenage Winter Wonderland Ltd | Arts & recreation | 2024 |
| Stewards Global Ltd | Wholesale & retail | 2023 |
| Stewarts Consultancy Limited | Professional & scientific | 2020 |
| STF Management Services Ltd | Real estate | 2024 |
| STN Cleaning Services Limited | Administrative & support | 2024 |
| Stone OVEN92 Ltd | Hospitality | 2026 |
| Stone Studios Management Limited | Households | 2017 |
| Stonehorse Finance Ltd | Financial services | 2015 |
| Stonehorse Land and Property Limited | Construction | 2025 |
| Stonemarblegranite Ltd | Manufacturing | 2022 |
| Stonewood Spaces Ltd | Construction | 2011 |
| Stortford Boats Ltd | Transport & logistics | 2018 |
| Story Consulting Ltd | Professional & scientific | 2023 |
| Storystone Ltd | Information & communication | 2025 |
| Strata Cost Consulting Limited | Professional & scientific | 2026 |
| Stratton Coachworks Ltd | Wholesale & retail | 2023 |
| Stratton Recruitment Services Ltd | Information & communication | 2019 |
| Stratton UK Property Ltd | Construction | 2020 |
| Street's Trading Limited | Wholesale & retail | 2014 |
| Stress 3 Recruitment Ltd | Administrative & support | 2026 |
| Strive Atlas Ltd | Wholesale & retail | 2022 |
| Stroe Haulage Ltd | Transport & logistics | 2025 |
| Stubbins Marketing Limited | Wholesale & retail | 1987 |
| Studio 27 Hair & Beauty Ltd | Other services | 2019 |
| Studio Cleaners Limited | Administrative & support | 2026 |
| Studio DAN Mumford Limited | Professional & scientific | 2018 |
| Studio Fogg Ltd | Arts & recreation | 2023 |
| Studio NEU Ltd | Manufacturing | 2025 |
| Studio Onur Ltd | Professional & scientific | 2022 |
| Style Concierge Ltd | Professional & scientific | 2026 |
| Style Slots Ltd | Information & communication | 2025 |