| SHL Design & Consultancy Ltd | Professional & scientific | 2021 |
| Shoebox Services Limited | Financial services | 2024 |
| SI Soft Ltd | Other services | 2012 |
| Sids News Limited | Wholesale & retail | 2012 |
| Sihotech Ltd. | Information & communication | 2012 |
| Simbiotec Limited | Information & communication | 2002 |
| Simon Smith Hairdressing Limited | Other services | 2014 |
| Simonds Mews Management Limited | Households | 2023 |
| Simonnet Sustainability Consultancy Ltd | Professional & scientific | 2024 |
| Simply ASK Ltd | Information & communication | 2020 |
| Singh Property Management Limited | Real estate | 2016 |
| Sippchoice Trustees Limited | Administrative & support | 2009 |
| SIX Hats Marketing Ltd | Professional & scientific | 2025 |
| SIX Heritage Ltd | Professional & scientific | 2023 |
| Sixten Contracting Services Ltd | Construction | 2009 |
| SJ Binnall Ltd | Arts & recreation | 2018 |
| SJC Armour Limited | Real estate | 2024 |
| Skapital Ltd | Professional & scientific | 2012 |
| Skeffs Ltd | Construction | 2019 |
| Skull Shaver EU Limited | Wholesale & retail | 2016 |
| Sky Blue Hospitality Ltd | Hospitality | 2018 |
| Sky East UK Ltd | Manufacturing | 2013 |
| Sky Full of Stars Limited | Education | 2024 |
| Skyhill Partners Ltd | Other services | 2021 |
| Skylark Business Services Ltd | Administrative & support | 2025 |
| Skylarke Ltd | Professional & scientific | 2025 |
| SLG 2026 Limited | Financial services | 2026 |
| Slink Supper Club Ltd | Arts & recreation | 2025 |
| SLM Advisory Ltd | Professional & scientific | 2026 |
| SLR Automotive Surrey Limited | Wholesale & retail | 2018 |
| Slumber Club Ltd | Education | 2023 |
| SMA Motors Ltd | Wholesale & retail | 2022 |
| Small & Mighty Play Hub Ltd | Arts & recreation | 2023 |
| Small Mouse Ltd | Professional & scientific | 2020 |
| Smart Electrons Ltd | Construction | 2017 |
| Smart FM Limited | Professional & scientific | 2007 |
| Smarter Sausages Ltd | Professional & scientific | 2018 |
| SME Assets Ltd | Financial services | 2025 |
| SME Development Ltd | Real estate | 2022 |
| SME General Building Ltd | Construction | 2019 |
| SME Portfolios Ltd | Real estate | 2025 |
| Smith & Young Ltd | Construction | 2015 |
| SN Godalming Ltd | Hospitality | 2026 |
| Snazzy Media Limited | Professional & scientific | 2011 |
| SNB Sachs Advisory Ltd | Professional & scientific | 2020 |
| Sneakybetts Ltd | Professional & scientific | 2018 |
| Snow Leopard Properties Ltd | Real estate | 2001 |
| Snow Peak London, Limited | Wholesale & retail | 2018 |
| Snuga Limited | Manufacturing | 2011 |
| Social Sequence Ltd | Information & communication | 2026 |
| SOCIAL42 Ltd | Professional & scientific | 2024 |
| Sofondem Ltd | Information & communication | 2021 |
| Solace Jewellery Ltd | Wholesale & retail | 2015 |
| Sole Systems Limited | Professional & scientific | 2004 |
| Solid INK Ltd | Other services | 2017 |
| Soska Ltd | Construction | 2017 |
| Source Auto Shipping Ltd | Wholesale & retail | 2026 |
| Sous LE Bois Ltd | Hospitality | 2021 |
| South Downs Campsite Limited | Hospitality | 2018 |
| South Downs Caravans Limited | Wholesale & retail | 2018 |
| South Downs Park Homes Limited | Hospitality | 2020 |
| Southern Area Roller Hockey Ltd | Arts & recreation | 1993 |
| Southern Education Associates Ltd | Education | 2013 |
| Southern Embers Ltd | Hospitality | 2026 |
| Southern Horizons Europe Limited | Administrative & support | 2005 |
| Southwell Compliance Limited | Professional & scientific | 2017 |
| SP HR Services Ltd | Administrative & support | 2017 |
| SP Watergate Limited | Real estate | 2012 |
| Spacemargin Residents Management Limited | Real estate | 1988 |
| Spark Innovative Ltd | Manufacturing | 2025 |
| Spartech Builds Limited | Manufacturing | 2024 |
| Special Needs Limited | Administrative & support | 2024 |
| Specialist Asset Finance Limited | Professional & scientific | 2017 |
| Specialist Firearms Consultancy Ltd | Professional & scientific | 2024 |
| Speech Therapy South London Ltd | Health & social care | 2017 |
| Speed 6 Consulting Ltd | Professional & scientific | 2024 |
| Spheresoft Ltd | Information & communication | 2014 |
| Spinning Poodle Limited | Manufacturing | 2019 |
| Spirit Consult Limited | Professional & scientific | 2009 |
| Splash Red Limited | Professional & scientific | 2023 |
| Spliced Media Limited | Information & communication | 2024 |
| Spontaneous Media Ltd | Information & communication | 2025 |
| Sport Exchange Limited | Arts & recreation | 2025 |
| Sport Media Information Limited | Education | 2019 |
| Sporting Phoenix Limited | Wholesale & retail | 2013 |
| SPR Labs Ltd | Information & communication | 2025 |
| Springhouse HR Limited | Professional & scientific | 2010 |
| Square 5 Square Ltd | Real estate | 2025 |
| Square Root Design Limited | Information & communication | 1990 |
| Squid Tech Ltd | Information & communication | 2025 |
| SS Offshore Tech Ltd | Professional & scientific | 2023 |
| Ssense Coaching Limited | Professional & scientific | 2020 |
| ST Extruded Products UK Ltd | Administrative & support | 2016 |
| ST James's Air Services Ltd | Transport & logistics | 2018 |
| ST Peter's Court Residents Company Limited | Households | 1993 |
| Stable Micro Systems (Holdings) Limited | Professional & scientific | 2015 |
| Stable Micro Systems Limited | Manufacturing | 1983 |
| Stagecoach Education Services Limited | Arts & recreation | 2016 |
| Stagecoach Performing Arts Limited | Administrative & support | 1994 |
| Stagedoor App UK Limited | Arts & recreation | 2016 |