| SO Bright, SO Loud Limited | Professional & scientific | 2013 |
| SO Cabelo Limited | Other services | 2008 |
| SO Technologies Limited | Information & communication | 2012 |
| Soares and White Ltd | Administrative & support | 2024 |
| Soars Performance Ltd | Wholesale & retail | 2021 |
| Social Butterfly Digital Ltd | Professional & scientific | 2023 |
| Social Care Practice Consultants (Scpc) Ltd | Health & social care | 2014 |
| Social Value 4 Real Limited | Professional & scientific | 2025 |
| Social Work Consultant Ltd | Health & social care | 2015 |
| Sofia Car Wash Ltd | Administrative & support | 2024 |
| Sofia Offshore Wind Farm Holdings Limited | Financial services | 2011 |
| Sofia Offshore Wind Farm Limited | Construction | 2011 |
| Sofol Ltd | Information & communication | 2014 |
| Sofra Plant Limited | Administrative & support | 2025 |
| Softestsols Ltd | Information & communication | 2017 |
| Softix Consulting Ltd | Information & communication | 2010 |
| Software Evolution Limited | Information & communication | 2012 |
| Sogesta Worldwide Ltd | Other services | 2011 |
| Soho Black Limited | Financial services | 2015 |
| Soigne Ltd | Wholesale & retail | 2020 |
| Soina Limited | Health & social care | 2019 |
| Soisun Ltd | Transport & logistics | 2019 |
| Soko PVT Limited | Health & social care | 2011 |
| Solace UNO Ltd | Information & communication | 2024 |
| Solana LLP | | 2020 |
| Solar Graphics & Exhibitions Ltd | Construction | 2020 |
| Solarnet Communications Limited | Information & communication | 2006 |
| Solatek Ltd | Wholesale & retail | 2017 |
| Solatek Renew Ltd | Wholesale & retail | 2024 |
| Solavia Group Ltd | Education | 2025 |
| Soldbysax Ltd | Wholesale & retail | 2025 |
| Soldev Trans Ltd | Transport & logistics | 2023 |
| Sole Mate Foot Care Ltd | Health & social care | 2018 |
| Sole Trader Courses Ltd | Education | 2025 |
| Soleluna Pizza 3 Ltd | Hospitality | 2022 |
| Solent Project Services Ltd | Information & communication | 2021 |
| Solent Village Management Company Limited | Real estate | 1990 |
| Solera Industries Ltd | Professional & scientific | 2022 |
| Solid Ground Real Estate Ltd | Real estate | 2022 |
| Soligo Lima Consultancy Ltd | Professional & scientific | 2026 |
| Solitaire Enterprises Limited | Real estate | 2003 |
| SOLITAIRE1066 LLP | | 2021 |
| SOLO16 Ltd | Information & communication | 2017 |
| Soloh Hair Ltd | Other services | 2023 |
| Solomon Training Limited | Administrative & support | 2003 |
| Solsey Waste and Environmental Limited | Water & waste | 2011 |
| Soltan Logistics Limited | Transport & logistics | 2025 |
| Soluna Consulting Ltd | Professional & scientific | 2024 |
| Solution Made Easy [SME] Limited | Extraterritorial | 2014 |
| SOM Foods Limited | Wholesale & retail | 2024 |
| SOM Services Limited | Transport & logistics | 2024 |
| Some 1 Limited | Construction | 2005 |
| Some Carrots Ltd | Information & communication | 2025 |
| Somerford Associates Limited | Administrative & support | 2001 |
| Somerford Geospatial Limited | Professional & scientific | 2025 |
| Somser Ltd | Financial services | 2019 |
| Sonicscan Limited | Information & communication | 1998 |
| Sonus Construction Ltd | Construction | 2026 |
| Sonus Structural Engineering Ltd | Professional & scientific | 2016 |
| Sorella Spa Ltd | Other services | 2010 |
| Soric Developments Limited | Hospitality | 1997 |
| SOT Transport Ltd | Transport & logistics | 2022 |
| Soter Compliance Ltd | Construction | 2025 |
| Soul Sister Property Ltd | Real estate | 2022 |
| Soul Sounds Collection Ltd | Health & social care | 2024 |
| Soul Therapy 1111 Ltd | Other services | 2022 |
| Soule Exterior Cleaning Ltd | Administrative & support | 2024 |
| Soulflava Ltd | Hospitality | 2025 |
| Soulventure Ltd | Wholesale & retail | 2024 |
| Sounds Like Women Community Interest Company | Information & communication | 2019 |
| Sounds Visual Music Ltd | Other services | 1993 |
| Sour Cream and Chive Ltd. | Wholesale & retail | 2015 |
| Source Energie Limited | Professional & scientific | 2020 |
| Source Energie Services Limited | Professional & scientific | 2012 |
| Source Galileo Development Services UK Ltd | Professional & scientific | 2023 |
| Source Galileo Limited | Professional & scientific | 2021 |
| Source Solutions London Ltd | Construction | 2022 |
| Sousa Cleaning Service Ltd | Administrative & support | 2022 |
| South Central Engineering Limited | Professional & scientific | 2016 |
| South Coast PMO Ltd | Professional & scientific | 2025 |
| South East Trans Co Ltd | Transport & logistics | 2019 |
| South West Car Buyers Ltd | Wholesale & retail | 2020 |
| South West Construction Management Ltd | Professional & scientific | 2020 |
| South West Electrical & Eco Tech Ltd | Other services | 2017 |
| South West Food Group (Wiltshire) Ltd | Wholesale & retail | 2025 |
| South West Groundwork’S & Civil Engineering Ltd | Construction | 2024 |
| South West Mortgage Solutions Limited | Financial services | 2002 |
| South West Plumbing and Heating Limited | Construction | 2021 |
| South West Properties (Swindon) Ltd. | Real estate | 2021 |
| South West Roofing Consultant's Ltd | Construction | 2022 |
| South West Swim Ltd | Arts & recreation | 2015 |
| South West Vauxhall Spares Ltd | Wholesale & retail | 2011 |
| South-Western Drivers Ltd | Administrative & support | 2011 |
| Southern Counties Civils Limited | Administrative & support | 2021 |
| Southernwood Solutions Limited | Information & communication | 2019 |
| Southleaze Xmas Trees Limited | Agriculture & fishing | 2003 |
| Southpaw Consulting Ltd | Professional & scientific | 2012 |
| Southpaw CX Ltd | Professional & scientific | 2018 |
| Southview Trading Limited | Wholesale & retail | 2024 |
| Southwest Healthcare Ltd | Health & social care | 2026 |