| Student Urban Living Bermondsey Limited | Construction | 2016 |
| Student Urban Living Edinburgh Limited | Construction | 2024 |
| Student Urban Living Guildford Limited | Real estate | 2020 |
| Student Urban Living Ilderton Limited | Construction | 2025 |
| Student Urban Living Leicester Limited | Construction | 2016 |
| Student Urban Living Lewisham Limited | Construction | 2021 |
| Studio 520 Limited | Education | 2017 |
| Studio Judith Ltd | Arts & recreation | 2023 |
| Studio TOM Rowland Limited | Professional & scientific | 2018 |
| Studio XQT Ltd | Manufacturing | 2025 |
| Study Active Limited | Education | 2015 |
| Styleplan Property Solutions Ltd | Construction | 2002 |
| SUB 1313 Ltd | Information & communication | 2026 |
| SUB Events Limited | Information & communication | 2024 |
| Subterra Living Ltd | Construction | 2025 |
| Successful Steps Education Ltd | Education | 2023 |
| Suffoca Limited | Professional & scientific | 2019 |
| Sugar Rush Properties Ltd | Real estate | 2016 |
| Sugarzoo Limited | Professional & scientific | 2010 |
| Sujatha Limited | Hospitality | 2009 |
| Suki's Svelte Limited | Arts & recreation | 2004 |
| SUL Design & Build Limited | Construction | 2014 |
| SUL Estates Ltd | Construction | 2019 |
| SUL Group Limited | Financial services | 2019 |
| Summit Building Ltd | Construction | 2023 |
| Summit Project Consultants Ltd | Construction | 2021 |
| Sun Care Living Limited | Health & social care | 2012 |
| Sun Street Management Company (Baldock) Limited | Extraterritorial | 1994 |
| Sundon Park (Hive) Management Company Limited | Real estate | 2000 |
| Sunny Homes Property Management Ltd. | Real estate | 2022 |
| Sunny QP Property LLP | | 2022 |
| Super Crown 07 Limited | Health & social care | 2024 |
| Supercolor Limited | Information & communication | 2021 |
| Superformance (UK) Limited | Wholesale & retail | 2006 |
| Superformance Global Products Limited | Wholesale & retail | 2017 |
| Superformance Limited | Professional & scientific | 2006 |
| Superhuman Teams Ltd | Information & communication | 2021 |
| Supertyres Motorists Centre (Welwyn) Limited | Wholesale & retail | 1983 |
| Superyacht Insurance Brokers Ltd | Financial services | 2016 |
| Supplygo Ltd | Administrative & support | 2020 |
| Support IT Labs Ltd | Extraterritorial | 2022 |
| Support Together Ltd | Administrative & support | 2024 |
| Supremacy Property Solutions Ltd | Real estate | 2022 |
| Sure House Ltd | Real estate | 2023 |
| Surebuild Homes Ltd | Construction | 2019 |
| Surge EV Ltd | Construction | 2025 |
| Surrey Hills Consulting Engineers Limited | Professional & scientific | 2015 |
| Surrey Mirrors Limited | Wholesale & retail | 2023 |
| Surrey Voices Limited | Arts & recreation | 2007 |
| SURVEYS365 Ltd | Construction | 2025 |
| Surya Imports and Exports Limited | Wholesale & retail | 2025 |
| Susan Hall & Co Solicitors Limited | Professional & scientific | 2018 |
| Sutha Aesthetic & Wellbeing Ltd | Other services | 2024 |
| SVS Displays Ltd | Manufacturing | 2024 |
| SW Adjusters & Surveyors Limited | Financial services | 2014 |
| Swagat KJ Ltd | Hospitality | 2025 |
| Swan Children's Homes Ltd | Health & social care | 2018 |
| Swan Independent Living Limited | Health & social care | 2009 |
| Swbg Gassys Hold Company Limited | Hospitality | 2025 |
| Swbg Holdings Limited | Financial services | 2025 |
| Sweenymarketingroup Limited | Administrative & support | 2026 |
| Sweet Britain Limited | Wholesale & retail | 2025 |
| Sweet&Co Ltd | Hospitality | 2025 |
| Swenson Avenue Limited | Real estate | 2021 |
| Swift Air Charter Services Ltd | Transport & logistics | 2023 |
| Switching on the Light Ltd | Construction | 2019 |
| Switchshop Holdings Limited | Wholesale & retail | 2017 |
| Switchshop Limited | Information & communication | 1999 |
| Swyft Properties Ltd. | Real estate | 2018 |
| Syched Ltd | Hospitality | 2022 |
| Sydney & Jaden Enterprises Ltd | Information & communication | 2015 |
| Sylvico Limited | Professional & scientific | 2017 |
| Symply Balloons Limited | Arts & recreation | 2026 |
| Synapse Connected Limited | Professional & scientific | 2017 |
| Synapse Technologies Ltd | Information & communication | 2025 |
| Syncopate Innovations Ltd | Information & communication | 2020 |
| Syncro Marketing Ltd | Professional & scientific | 2023 |
| Synelec Ltd | Extraterritorial | 2019 |
| Synergen Power Limited | Extraterritorial | 2022 |
| Synergy Construction Limited | Construction | 2021 |
| Synergy Design Limited | Extraterritorial | 2019 |
| Synergy Developments Limited | Financial services | 2017 |
| Synergy Developments One Limited | Construction | 2019 |
| Synergy Developments Three Limited | Real estate | 2016 |
| Synergy Developments Two Limited | Real estate | 2012 |
| Synergy Group Holdings Limited | Financial services | 2016 |
| Synergy Group Management Limited | Professional & scientific | 2019 |
| Synergy Ireland Limited | Extraterritorial | 2022 |
| Synergy Mechanical and Electrical Limited | Extraterritorial | 2021 |
| Synergy Mechanical Limited | Extraterritorial | 2021 |
| Synergy Project Management Limited | Extraterritorial | 2022 |
| Synergy Property Global Limited | Construction | 2022 |
| Synergy Property Group Limited | Extraterritorial | 2012 |
| Synergy Property Holdings Limited | Extraterritorial | 2022 |
| Syntax Systems Solutions Limited | Professional & scientific | 2017 |
| Syrros Group Limited | Administrative & support | 1999 |
| T a Water Consultants Ltd | Water & waste | 2021 |
| T Infinity Trading Ltd | Wholesale & retail | 2025 |
| T J Coull Ltd | Information & communication | 2021 |
| T J Lakh Limited | Administrative & support | 2009 |