| South Eastern Carriage Company Limited | Extraterritorial | 2011 |
| Southeast and London Breast Care Limited | Health & social care | 2015 |
| Southern Tailoring Services Limited | Other services | 1998 |
| Southernwood Consultants Limited | Administrative & support | 2000 |
| Sovereign Court Residents Association Limited | Households | 1987 |
| Sparkle Catering Ltd | Financial services | 2024 |
| Spazio Interiors Limited | Construction | 2017 |
| Spencer & Associates Limited | Other services | 2017 |
| Spetacular Ltd | Wholesale & retail | 2024 |
| Spiller Electrical Services Ltd | Construction | 2021 |
| Spinnaker Trust Limited | Education | 2005 |
| Splash Attack Ltd | Other services | 2025 |
| Sports Focus Coaching Limited | Education | 2017 |
| Sports Management (UK) Limited | Administrative & support | 1998 |
| Spring Advisory Limited | Professional & scientific | 2006 |
| Springwood Norfolk Limited | Households | 2026 |
| Spry and Marshall Ltd | Construction | 2025 |
| Square Edge Developments Ltd | Real estate | 2026 |
| Square Edge Group Ltd | Financial services | 2026 |
| ST Michaels Facilities Management Limited | Households | 2017 |
| ST Peter's Green Estate Management Company Limited | Households | 2009 |
| ST Trading Asset Management Ltd | Other services | 2025 |
| Stacey Haynes MM Limited | Arts & recreation | 2024 |
| Standard Rack Limited | Wholesale & retail | 2026 |
| Standard Shelf Limited | Wholesale & retail | 2024 |
| Stanley Cool Mechanical Ltd | Construction | 2024 |
| Stansfield Family Limited | Financial services | 2026 |
| Stansfield Properties Ltd | Real estate | 2017 |
| Start-Driving Limited | Education | 2018 |
| Step Internet Limited | Administrative & support | 2011 |
| Steve Chamberlain Coaching Ltd | Professional & scientific | 2024 |
| Stevenage Conference Centre Limited | Hospitality | 2015 |
| STM Recruitment Limited | Administrative & support | 2021 |
| Stoneline Agencies Ltd | Wholesale & retail | 2003 |
| Stormless Limited | Administrative & support | 2023 |
| Storyforge Labs Ltd | Information & communication | 2026 |
| Storysearch Games Ltd | Information & communication | 2025 |
| Stratagem Tech Solutions Limited | Information & communication | 2018 |
| Strategy Feast Limited | Professional & scientific | 2017 |
| Stratton Gurney Estates Limited | Real estate | 2017 |
| Street Building Services Ltd | Construction | 2024 |
| Strengthening Minds Ltd | Other services | 2015 |
| Strengthening Minds UK C.I.C. | Education | 2019 |
| Struccrush Ltd | Construction | 2025 |
| Studio 212 Ltd | Professional & scientific | 2015 |
| Studioto Limited | Professional & scientific | 2013 |
| Sublime Beauty Limited | Other services | 2023 |
| Sully’S Properties Ltd | Real estate | 2025 |
| Summerhill Villas Limited | Real estate | 1992 |
| Sunridge Associates Limited | Education | 2014 |
| Sunspot App Ltd | Information & communication | 2025 |
| Supashine Valeting Retail Limited | Administrative & support | 2008 |
| Supergolden Media Ltd | Professional & scientific | 2022 |
| Supinie Solutions Ltd | Information & communication | 2023 |
| Supreme Cooling Services Limited | Construction | 2023 |
| Surface Designs London Limited | Construction | 2024 |
| Surge Homes Ltd | Construction | 2025 |
| Surrey & Sussex EYE Surgery Ltd | Health & social care | 2014 |
| SV Roofing & Renovation Limited | Administrative & support | 2016 |
| SW Global Solutions Ltd | Information & communication | 2018 |
| Swordsman Motors Ltd | Wholesale & retail | 2025 |
| SWS Investments Ltd | Other services | 2020 |
| SY Limited | Professional & scientific | 2002 |
| Symboli Ltd | Wholesale & retail | 2025 |
| Symmetry Studios Ltd | Professional & scientific | 2016 |
| Sync-Link Properties Ltd | Real estate | 2025 |
| Synergy Outsourcing Limited | Information & communication | 1999 |
| SYX Media Limited | Professional & scientific | 2025 |
| T&B Consulting Services Ltd | Professional & scientific | 2018 |
| T&M Commercial Services Ltd | Professional & scientific | 2023 |
| T. Walsh Investments Limited | Real estate | 1959 |
| T.D Home Services Ltd | Construction | 2020 |
| Taaj Family Limited | Wholesale & retail | 2021 |
| Tabletop Tea-W Limited | Hospitality | 2025 |
| Tacaro Limited | Professional & scientific | 2014 |
| Tadb Holdings Ltd | Professional & scientific | 2022 |
| Talent Storm Recruitment Ltd | Administrative & support | 2018 |
| Talentum Associates Ltd | Professional & scientific | 2021 |
| Tamsyn Clark Ltd | Administrative & support | 2011 |
| Tanners Training and Development Consultancy Limited | Education | 2014 |
| Tapmedia Ltd | Information & communication | 2010 |
| Taylor MAY Ltd. | Real estate | 2018 |
| Taylor MAY Property Ltd | Construction | 2020 |
| Tech 52 Limited | Information & communication | 2026 |
| Tech Hubble Ltd | Information & communication | 2022 |
| Tedbert Limited | Administrative & support | 2016 |
| Tekton Global Ltd | Wholesale & retail | 2024 |
| Templepark Limited | | 1983 |
| Temptis Consultancy Limited | Real estate | 2025 |
| Terry Benson Associates Limited | Information & communication | 2005 |
| Test Gear Limited | Construction | 2012 |
| Tethyan Global Resources Limited | Financial services | 2025 |
| Tetra RHO Ltd | Real estate | 2024 |
| Thai Today Limited | Hospitality | 2016 |
| Thakuria Investments Ltd | Real estate | 2022 |
| Thames GAS Heating Electrical Ltd | Construction | 2021 |
| Thanh's Properties LLP | | 2025 |
| That Watch Ltd | Wholesale & retail | 2019 |
| THE 5TH Emergency Service Ltd | Information & communication | 2025 |
| THE Beauty Rooms (Chislehurst) Ltd | Other services | 2012 |