| Solarbox London Ltd | Professional & scientific | 2014 |
| Sole Space Properties Limited | Real estate | 2024 |
| Solid Digital Marketing Ltd | Information & communication | 2015 |
| Solidrock Built Ltd | Real estate | 2025 |
| Sollers Solutions Ltd | Information & communication | 2025 |
| Sols Consulting Limited | Administrative & support | 2018 |
| Solstice Oncology UK Limited | Professional & scientific | 2026 |
| Solunexa Medispa & Clinic Limited | Real estate | 2022 |
| Solutions 365 Ltd | Information & communication | 2021 |
| Solutions POD Limited | Information & communication | 2020 |
| Solved Consultancy Group Limited | Professional & scientific | 2020 |
| Solvena Systems Ltd | Information & communication | 2026 |
| Solvents Industry Association Limited | Other services | 1973 |
| Somerford Booths Hall Management Limited | Real estate | 2020 |
| Something More Productive Ltd | Hospitality | 2023 |
| Somie Property Group Ltd | Real estate | 2020 |
| Somo Bridging Two Limited | Financial services | 2019 |
| Somo Credit Limited | Financial services | 2020 |
| Somo Holdings Limited | Financial services | 2020 |
| Song Consultant Limited | Professional & scientific | 2008 |
| Sonia Medics Limited | Health & social care | 2017 |
| Sonja Keselj Limited | Professional & scientific | 2026 |
| Sonnos Limited | Administrative & support | 2014 |
| Sonü Properties Holdings Limited | Financial services | 2023 |
| Sonü Properties Limited | Construction | 2022 |
| Soofi Investments Limited | Real estate | 2024 |
| Soon Xpress Logistics Ltd | Transport & logistics | 2025 |
| Sophbloss Ltd | Wholesale & retail | 2023 |
| Sophiah Edward Group Ltd | Professional & scientific | 2025 |
| Sophometrics Ltd | Administrative & support | 2021 |
| Sorted Accounting Limited | Professional & scientific | 2026 |
| SOT Capital Ltd | Wholesale & retail | 2017 |
| Soulsa Services & Productions Limited | Professional & scientific | 2018 |
| Soundtag Limited | Professional & scientific | 2025 |
| Source Genie Ltd | Professional & scientific | 2021 |
| Source of Inspiration Limited | Financial services | 1994 |
| Sourcing Matters Limited | Administrative & support | 2017 |
| South Bar Doctors Limited | Administrative & support | 2009 |
| South Manchester Synagogue Limited | Other services | 2008 |
| South West Joinery Ltd | Manufacturing | 2018 |
| Southbank (Altrincham) Management Company Limited | Households | 2022 |
| Southbourne Rose Limited | Real estate | 2020 |
| Southcharts Limited | Households | 1977 |
| Southend Estates Group Limited | Real estate | 1900 |
| Southend-On-Sea Estates Company Limited(The) | Professional & scientific | 1964 |
| Southerley Limited | Administrative & support | 2004 |
| Southern Green Properties Limited | Construction | 2019 |
| Southfields Management Co. Limited | Households | 1980 |
| Southi Investment Ltd | Real estate | 2022 |
| Southlawn Management Company Limited | Households | 1985 |
| Sovereign Clouds Limited | Hospitality | 2023 |
| Sovereign New House Ltd | Households | 2014 |
| SP Analytics Limited | Administrative & support | 2025 |
| SP Architects Limited | Professional & scientific | 2008 |
| SP Development Partners Limited | Construction | 2025 |
| SP Education Strategies Limited | Professional & scientific | 2025 |
| SP Landscapes Ltd | Administrative & support | 2017 |
| SP Property Consultants Ltd | Professional & scientific | 2021 |
| SP Realisations Limited | Hospitality | 2012 |
| Sp-Shah Limited | Hospitality | 2024 |
| Spa Pedicure Studio Ltd | Other services | 2026 |
| Spa Property Limited | Real estate | 2001 |
| Space to Live Limited | Real estate | 2024 |
| Spacefit UK Limited | Construction | 2016 |
| Spacescape Limited | Construction | 2001 |
| Spacing Guild UK Limited | Manufacturing | 2022 |
| Spakle Kleaning and Logistics Services Ltd | Transport & logistics | 2025 |
| Spaldwick Consulting Limited | Administrative & support | 2014 |
| Spark Commodities UK Ltd | Administrative & support | 2022 |
| Spark Digital Management Ltd | Financial services | 2023 |
| Spark Digital Trading (UK) LLP | | 2022 |
| Spark Engine Ltd | Information & communication | 2012 |
| Spark LED Lighting Ltd | Construction | 2013 |
| Spark Marketing & Design Ltd | Professional & scientific | 2020 |
| Spark Property Investments Limited | Real estate | 2012 |
| Sparklestreet HQ Limited | Real estate | 2004 |
| Sparklestreet Projects Limited | Professional & scientific | 2011 |
| Sparva Properties | | 1990 |
| Spatial Plus Ltd | Wholesale & retail | 2022 |
| Speakable Skills Limited | Education | 2025 |
| Speaklife Consulting Ltd | Information & communication | 2018 |
| Speaklife Properties Limited | Real estate | 2022 |
| Speaklive Consulting Ltd | Information & communication | 2025 |
| Speakwell Therapy Limited | Professional & scientific | 2026 |
| Spearhead IP Ltd | Arts & recreation | 2022 |
| Special Technology Limited | Wholesale & retail | 2024 |
| Specialist Chest Radiology Services Limited | Health & social care | 2022 |
| Specialist DOC Limited | Health & social care | 2025 |
| Specialist Group Limited | Wholesale & retail | 1970 |
| Specialist Operations Support Limited | Real estate | 2020 |
| Specifier Samples Limited | Construction | 2005 |
| Spectra Business Solutions Ltd | Administrative & support | 2011 |
| Spectra Compliance Limited | Professional & scientific | 2016 |
| Spectra Construction Management Limited | Professional & scientific | 2023 |
| Spectra HR Limited | Administrative & support | 2011 |
| Spectra Safety Limited | Administrative & support | 2013 |
| Spectra-Physics Holdings Limited | Financial services | 1987 |
| Spectre (Hayes) Limited | Construction | 2015 |
| Spectrum Apollo Limited | Administrative & support | 2024 |
| Spectrum Energy Limited | Financial services | 2024 |