| Snowy Midco 2 Limited | Financial services | 2022 |
| Snowy Topco Limited | Financial services | 2022 |
| SNP Group Ltd | Real estate | 2025 |
| SO Car Limited | Wholesale & retail | 2016 |
| SO Holdings Ltd | Real estate | 2024 |
| SO Impressed! Corporate & Retail Services Ltd | Other services | 2012 |
| Soccer Coaching Limited | Administrative & support | 2000 |
| Societas Consult Ltd | Professional & scientific | 2024 |
| Socolov Build Ltd | Manufacturing | 2024 |
| Sofil Logistics Limited | Transport & logistics | 2017 |
| Softech Global Limited | Information & communication | 2025 |
| Softtalk Consultancy Limited | Professional & scientific | 2002 |
| Sohni Home Ltd | Other services | 2023 |
| Solando Ltd | Wholesale & retail | 2025 |
| Solar Leisure Vehicles Ltd | Wholesale & retail | 2013 |
| Solasta Dynamic Ltd | Information & communication | 2012 |
| Solaston Limited | Other services | 2022 |
| Solgrow Ltd | Wholesale & retail | 2007 |
| Solomon Associates Limited | Professional & scientific | 1990 |
| Solomon Beck Limited | Hospitality | 2020 |
| SOM SAA Ltd | Hospitality | 2014 |
| Somerset & Dorset Railway Trading Company Limited | Wholesale & retail | 2022 |
| Somerville Ascend Limited | Professional & scientific | 2025 |
| Somewhen Ltd | Hospitality | 2024 |
| Sondex Limited | Professional & scientific | 2002 |
| Sondex Wireline Limited | Mining & quarrying | 1998 |
| Sonic Swan Limited | Information & communication | 2014 |
| Sonticus Limited | Administrative & support | 2013 |
| Sonu Kang Limited | Construction | 2025 |
| Sonuus Limited | Manufacturing | 2009 |
| Sorted Sales Solutions Ltd | Administrative & support | 2026 |
| Sound Control Technologies UK Limited | Manufacturing | 2021 |
| Source UPS Ltd | Information & communication | 2008 |
| South East Scaffold Limited | Construction | 2023 |
| South Farnborough Working Mens Club Limited | Other services | 2012 |
| South London Electrical Ltd | Construction | 2023 |
| Southampton Property Limited | Wholesale & retail | 2003 |
| Southern Counties Building Solutions Ltd | Construction | 2012 |
| Southern Domestic Services Ltd | Other services | 2018 |
| Southern Star Research (UK) Ltd | Extraterritorial | 2014 |
| Southern Voices for Global Development | Health & social care | 2007 |
| Souvenir London Ltd | Wholesale & retail | 2023 |
| Souvenir Tattoo Ltd | Arts & recreation | 2025 |
| Sovereign Aliance Limited | Financial services | 2026 |
| Sovereign Snooker Ltd | Other services | 2000 |
| Sovos Compliance Limited | Professional & scientific | 2003 |
| Sovos Compliance UK Holding Limited | Financial services | 2017 |
| SP23 Limited | Hospitality | 2023 |
| Space and Time Reclaimed Ltd | Other services | 2025 |
| Sparrow Health Care Ltd | Administrative & support | 2019 |
| Spartan Energy Limited | Wholesale & retail | 2025 |
| Spartan Landscapes Ltd | Professional & scientific | 2025 |
| SPB BIA and Care Consultancy Ltd | Health & social care | 2025 |
| Specbud Limited | Construction | 2022 |
| Speed Dryline Ltd | Construction | 2020 |
| Speedlink Transport Limited | Transport & logistics | 2006 |
| Spencer Frames and Structures Ltd | Manufacturing | 2024 |
| Spenley Limited | Professional & scientific | 2016 |
| Spira Films Limited | Information & communication | 2024 |
| Split Screen Systems Limited | Information & communication | 2004 |
| Sportsmans Court Management Co Ltd | Households | 1998 |
| Spraytech Accident Repairs Ltd | Wholesale & retail | 2018 |
| Spring Financial Services Limited | Professional & scientific | 2001 |
| Square Mile Wellbeing Ltd | Health & social care | 2016 |
| Squarezone Limited | Information & communication | 1985 |
| Squirrel Accountancy Limited | Professional & scientific | 2011 |
| Squirrels Educare Limited | Education | 2009 |
| SR Digital Management Limited | Administrative & support | 2018 |
| SR20 Ltd | Hospitality | 2023 |
| SR23 Limited | Financial services | 2023 |
| SR73 Ltd | Hospitality | 2018 |
| Sree SAI PVT Ltd | Hospitality | 2024 |
| SS Exterior Cleaning Ltd | Administrative & support | 2024 |
| SSBM23 Ltd | Hospitality | 2022 |
| Ssbs London Ltd | Manufacturing | 2018 |
| Ssbs Property Management Ltd | Real estate | 2025 |
| ST George Electrical Limited | Construction | 2016 |
| ST John's and Spring Grove Community Association Limited | Other services | 1997 |
| ST. George Facilities Limited | Construction | 2008 |
| ST. John's Court Management Company NO. 2 Limited | Households | 2011 |
| Staffordshire & Midlands Time Recorders Limited | Extraterritorial | 2002 |
| Stakhanov Industries Ltd | Information & communication | 2014 |
| Stamford Estate Planning Ltd | Professional & scientific | 2009 |
| Stamford Storage Services Ltd | Professional & scientific | 2009 |
| Standswell Ltd | Professional & scientific | 2018 |
| Starflight Aviation Holdings Limited | Transport & logistics | 2010 |
| Starflight Aviation International Limited | Transport & logistics | 1998 |
| Starflight Aviation Limited | Transport & logistics | 1989 |
| Stark Consultants Limited | Information & communication | 2018 |
| Starkwood Media Group Limited | Information & communication | 2000 |
| Starlane Insurance Services Limited | Financial services | 2002 |
| Starlight Courier Ltd | Transport & logistics | 2019 |
| Starting Line Solutions Ltd | Professional & scientific | 2010 |
| Starvector Limited | Professional & scientific | 2019 |
| Stay Apartments & Lodges LLP | | 2020 |
| Steadman Machine Tools Services Limited | Manufacturing | 2002 |
| Steamy Business Ltd | Other services | 2024 |
| Steelbeam Installers Limited | Construction | 2022 |
| Stefy Cleaning Ltd | Construction | 2020 |
| Stelson Limited | Households | 1983 |