| Simply Granite Limited | Construction | 2006 |
| Simply Hear Ltd | Wholesale & retail | 2024 |
| Simply Modular UK Ltd | Professional & scientific | 2020 |
| Simplygenius.Ai Ltd | Information & communication | 2025 |
| Simpsons Solicitors Limited | Professional & scientific | 2015 |
| Simurgh Property Group Ltd | Administrative & support | 2025 |
| SIP Organisation Ltd | Construction | 2025 |
| Sipmonton Ltd | Hospitality | 2024 |
| Sisto Compliance Ltd | Construction | 2015 |
| Sitarah Ltd | Extraterritorial | 2024 |
| Site Engineer Ltd | Construction | 2004 |
| SIZZLE29 Ltd | Hospitality | 2026 |
| Sjasin Ltd | Wholesale & retail | 2024 |
| SJB Consultant Services Ltd | Professional & scientific | 2025 |
| Sjfh Consultants Limited | Information & communication | 2008 |
| SJH Sports Ventures Limited | Other services | 2014 |
| SJL Print Supplies Ltd | Wholesale & retail | 2018 |
| SJM Enterprises Limited | Professional & scientific | 2003 |
| SK Autos Motive Ltd | Wholesale & retail | 2019 |
| SK Data Labs Ltd | Information & communication | 2026 |
| SK Education Services Ltd | Education | 2015 |
| SK Financial Management Ltd. | Financial services | 2001 |
| SK Football Coaching Ltd | Arts & recreation | 2019 |
| SK Painting & Decorating Services Ltd | Construction | 2022 |
| SK Podiatry Ltd | Health & social care | 2024 |
| SK Quality Construction Ltd | Construction | 2021 |
| SK Services Group Limited | Other services | 2025 |
| SK-9 Spa Ltd | Other services | 2016 |
| SK4 Holdings Ltd | Financial services | 2025 |
| SK8 Roofing Ltd | Construction | 2024 |
| SK8 Tyres Ltd | Wholesale & retail | 2017 |
| SK81BH Ltd | Real estate | 2026 |
| Skelton Property Consultancy Limited | Professional & scientific | 2013 |
| Skfc Community Interest Company | Arts & recreation | 2025 |
| Skill Hub Academy Ltd | Education | 2023 |
| Skilledup Life Ltd | Administrative & support | 2021 |
| Skina Laser 1 Ltd | Health & social care | 2025 |
| Skinfluential Limited | Wholesale & retail | 2021 |
| SKS Ventures Limited | Hospitality | 2013 |
| Sky Flair Limited | Construction | 2007 |
| Sky VU Ltd | Real estate | 2026 |
| Skyddex Ltd | Information & communication | 2025 |
| Skylark Biomass Ltd | Energy | 2020 |
| Skymaster Air Cargo Limited | Transport & logistics | 1990 |
| Slater Carpentry Limited | Manufacturing | 2026 |
| Slbp Properties Ltd | Real estate | 2025 |
| SLJ Holdings Limited | Financial services | 2017 |
| Slmc QA Services Limited | Professional & scientific | 2025 |
| Slot Property Ltd | Construction | 2022 |
| SLS Nationwide Ltd | Professional & scientific | 2016 |
| Slwb Ltd | Financial services | 2025 |
| SM Akstart Holdings Limited | Professional & scientific | 2023 |
| SM CBT Services Ltd | Health & social care | 2016 |
| SMA Property Services Ltd | Real estate | 2006 |
| Smail Estates Ltd | Real estate | 2025 |
| Smail Group Ltd | Financial services | 2023 |
| Smallpetselect Ltd | Wholesale & retail | 2018 |
| Smart Dental Care Limited | Administrative & support | 2008 |
| Smart Homes MGT Limited | Real estate | 2023 |
| Smart Irrigation Solutions Ltd | Construction | 2025 |
| Smart Jones Limited | Professional & scientific | 2005 |
| Smart Space Solutions 24 Ltd | Health & social care | 2024 |
| Smart WS Limited | Manufacturing | 2022 |
| Smartmed Ltd | Health & social care | 2013 |
| Smartzon Property Solutions Limited | Real estate | 2018 |
| Smartzon Technologies Ltd | Information & communication | 2022 |
| Smile Clinics Limited | Health & social care | 2009 |
| Smis Property Group Ltd | Real estate | 2026 |
| Smith Brothers Contract Services Ltd | Professional & scientific | 2020 |
| Smithson Howard Limited | Administrative & support | 2007 |
| Smithsonite Ltd | Information & communication | 2013 |
| SMK Education Ltd | Education | 2024 |
| SML Cafe Ltd | Hospitality | 2019 |
| Smnscu Ltd | Professional & scientific | 2019 |
| Smpi Ltd | Real estate | 2022 |
| Smrm Properties Limited | Real estate | 2022 |
| SMS Pro Soccer Ltd | Education | 2022 |
| Smzr Motors Limited | Wholesale & retail | 2025 |
| SN Jones Building & Joinery Ltd | Construction | 2024 |
| SN Jones Property Holdings Ltd | Hospitality | 2024 |
| Snape Estate Agents Holdings Limited | Real estate | 1991 |
| Snapes Developments Limited | Real estate | 1994 |
| Snapford Limited | Information & communication | 2001 |
| SNC NW Limited | Health & social care | 2025 |
| SNM Homes Ltd | Real estate | 2025 |
| Snotbricks Ltd | Wholesale & retail | 2025 |
| Snow Leopard 804 Ltd | Real estate | 2026 |
| Snowcool Limited | Real estate | 2002 |
| Snowdonia View Management Ltd | Households | 2019 |
| Snug Property Group Ltd | Real estate | 2019 |
| SNW Property (UK) Limited | Real estate | 2022 |
| So-Sage Consultancy Ltd | Health & social care | 2015 |
| Soar & Celebrate Limited | Arts & recreation | 2025 |
| Social Care Consultancy Ltd | Professional & scientific | 2020 |
| Social Media Kickstarter Training Ltd | Education | 2021 |
| Socially Synced Media Ltd | Professional & scientific | 2023 |
| Sofia Alexandra Property Management Ltd | Real estate | 2020 |
| Sokai Digital Ltd | Information & communication | 2022 |
| Soko Soko Ltd | Wholesale & retail | 2025 |
| Sol's Catering Limited | Hospitality | 2012 |