| Smet Limited | Manufacturing | 2008 |
| Smile Smart Technology Ltd | Manufacturing | 2009 |
| Smiles & Spaces Limited | Real estate | 2025 |
| Smit Marketing Ltd | Professional & scientific | 2025 |
| Smith & Gilmour Limited | Information & communication | 1997 |
| Smith Brickwork Limited | Construction | 2012 |
| SMJ (UK) Ltd | Extraterritorial | 2001 |
| SMK International Properties Ltd | Real estate | 2016 |
| SMW Financial Limited | Administrative & support | 2012 |
| SNAP-25 Marketing Ltd | Professional & scientific | 2014 |
| Snatig UK Limited | Wholesale & retail | 2019 |
| SNC Utilities Ltd | Construction | 2020 |
| Snelsmore Estates Limited | Hospitality | 1988 |
| SNJ Property LLP | | 2008 |
| Snowfox Management Limited | Real estate | 2023 |
| Snsdp Limited | Health & social care | 2023 |
| Snug Kitchen Design Limited | Construction | 2012 |
| Social Rebel Ltd | Professional & scientific | 2018 |
| Software Enterprises (UK) Limited | Information & communication | 1995 |
| Soho Showjumping Limited | Agriculture & fishing | 2024 |
| Solar Carparks Limited | Manufacturing | 2015 |
| Solar Energy Installers LLP | | 2010 |
| Solar Frame Solutions Limited | Professional & scientific | 2016 |
| Solareight Ltd | Construction | 2023 |
| Solareleven Ltd | Construction | 2024 |
| Solarnine Ltd | Construction | 2023 |
| Solarone Ltd | Construction | 2020 |
| Solarretail Ltd | Energy | 2023 |
| Solarseven Ltd | Construction | 2020 |
| Solarsix Ltd | Construction | 2023 |
| Solarten Ltd | Construction | 2023 |
| Solarthree Ltd | Construction | 2020 |
| Solartwelve Ltd | Construction | 2024 |
| Solarwinds Software UK Limited | Information & communication | 2015 |
| Solo Electrics Limited | Construction | 2004 |
| Solo Express Ltd | Professional & scientific | 2019 |
| Solomon Jacob Limited | Information & communication | 2006 |
| Solutionwright Ltd | Professional & scientific | 2018 |
| Solving Limited | Administrative & support | 1998 |
| SON Francisco Limited | Extraterritorial | 1981 |
| Song Division UK PTE Ltd | Other services | 2016 |
| Sonia Youd Associates Limited | Professional & scientific | 2011 |
| Sonic Laboratories Limited | Health & social care | 2007 |
| Sonning Flowers Ltd | Wholesale & retail | 2008 |
| Sonora Analytic Solutions Ltd | Information & communication | 2025 |
| Sonosine Limited | Professional & scientific | 2015 |
| Sootspasta Limited | Hospitality | 2025 |
| Sophie Patrikios Consulting Limited | Professional & scientific | 2017 |
| Sorce Limited | Information & communication | 2001 |
| Souqbox Limited | Information & communication | 2017 |
| South Bucks Windows Ltd | Construction | 2018 |
| South Central Conversions Ltd | Manufacturing | 2026 |
| South Central Hockey Limited | Arts & recreation | 2021 |
| South England Solar and Electrical Ltd | Construction | 2022 |
| Southern Counties Marble and Granite Limited | Manufacturing | 1986 |
| Southern Ductwork Services Limited | Other services | 2014 |
| Southern Energy Consultants Ltd | Professional & scientific | 2009 |
| Southern Hub Ltd | Wholesale & retail | 2023 |
| Southern Maintenance Solutions (UK) Limited | Construction | 1994 |
| Southfould Limited | Households | 2001 |
| Southview Gardens Freehold Ltd | Households | 2012 |
| Southview Gardens Management Limited | Households | 1989 |
| Souzou Enterprises Ltd | Other services | 2021 |
| SP Sharma Limited | Information & communication | 2018 |
| Space Panda Holdings Ltd | Wholesale & retail | 2023 |
| Space Solar Engineering Limited | Manufacturing | 2023 |
| Space Solar Group Holdings Limited | Financial services | 2022 |
| Space Solar Group Services Limited | Professional & scientific | 2023 |
| Space Solar Innovations Limited | Professional & scientific | 2022 |
| Spaces for Youth Ltd | Arts & recreation | 2025 |
| Sparhawke Ltd | Construction | 2011 |
| Sparrow House Consulting Ltd | Information & communication | 2019 |
| Spatial Days Limited | Information & communication | 2010 |
| Spattered Ltd | Professional & scientific | 2020 |
| SPD Design & Engineering Ltd | Professional & scientific | 2015 |
| Spearman Limited | Professional & scientific | 2012 |
| Specialist Auctions Ltd | Wholesale & retail | 2006 |
| Specialist Veterinary Cardiology Consultancy Ltd | Professional & scientific | 2010 |
| Specialized Concept Store (Newbury) Ltd | Wholesale & retail | 2012 |
| Spectroma Limited | Professional & scientific | 2020 |
| Speed 2911 Limited | Administrative & support | 1992 |
| Speedwell Automation Ltd | Manufacturing | 1996 |
| Spellers Accountancy Services Limited | Professional & scientific | 2005 |
| Spinestar Limited | Extraterritorial | 2022 |
| SPM Property Services Ltd | Real estate | 2018 |
| Sprayitrite UK Limited | Wholesale & retail | 2022 |
| Spriggs Chiropractic Limited | Health & social care | 2014 |
| Spriggs Nutrition Limited | Health & social care | 2016 |
| Spring Homes (UK) Limited | Construction | 2001 |
| Spring Time Catering Ltd | Hospitality | 2023 |
| Spring Ventures LLP | | 2010 |
| Spring Ventures Nominees Limited | Financial services | 2010 |
| Spry FOX Networks Limited | Information & communication | 2014 |
| Spurfect Fencing Solutions Ltd | Administrative & support | 2025 |
| Squadron Web Limited | Information & communication | 2013 |
| Square Mile Connections Limited | Professional & scientific | 2005 |
| Square Properties (Newbury) Limited | Households | 1958 |
| Squeegee & INK Ltd | Manufacturing | 2020 |
| Squeeze the Lemon Ltd | Information & communication | 2025 |
| Squinch Investments Limited | Real estate | 2025 |