| Sisco Equipment Limited | Wholesale & retail | 2021 |
| Sismep Ltd | Construction | 2019 |
| Sisqs Ltd | Administrative & support | 2019 |
| Sitabie Limited | Real estate | 2024 |
| Site Investments Limited | Wholesale & retail | 2018 |
| Sitorina Limited | Hospitality | 2017 |
| Sitos Cafe Ltd | Hospitality | 2025 |
| Sitos Franchise Limited | Hospitality | 2025 |
| Siuper Subs Ltd | Arts & recreation | 2025 |
| Sixcor Bar Limited | Hospitality | 2025 |
| Sixth Street Asset Management Ltd | Real estate | 2017 |
| Siyaary Limited | Health & social care | 2016 |
| SJ Property Holdings Ltd | Real estate | 2019 |
| SJ Sunrise LLP | | 2023 |
| SJ2 Properties Limited | Real estate | 2019 |
| SJH Flooring Contractors Limited | Construction | 2014 |
| Sjjr Property Limited | Real estate | 2021 |
| Sjpb Limited | Professional & scientific | 2012 |
| SJW Advice Limited | Financial services | 2026 |
| SK Aesthetics Limited | Health & social care | 2022 |
| SK Giggles Ltd | Wholesale & retail | 2025 |
| Skad & Garter Ltd | Wholesale & retail | 2026 |
| Skda Enterprises Ltd | Wholesale & retail | 2025 |
| Skellig Ltd | Professional & scientific | 2014 |
| Skiba Driving Ltd | Transport & logistics | 2017 |
| Skillme Language Limited | Education | 2021 |
| Skills Link Personal Development C.I.C. | Education | 2025 |
| Skittleshop Ltd | Wholesale & retail | 2025 |
| Skkt Property Ltd | Real estate | 2025 |
| SKR Chauffeur Service Ltd | Transport & logistics | 2026 |
| SKS Building Contractors Ltd | Construction | 2020 |
| Sky Metal Cleaning Limited | Manufacturing | 2025 |
| Sky Scaffolding (Middlesex) Ltd | Construction | 2016 |
| Skyco-London Ltd | Other services | 2020 |
| Skyhigh Marketing & Business Solutions Limited | Wholesale & retail | 2019 |
| Skyhight Ltd | Other services | 2024 |
| Skylight Interactive Ltd | Information & communication | 2009 |
| Skylight Management Limited | Real estate | 2025 |
| Skylight Windows Ltd | Manufacturing | 2022 |
| Skyline Property Holdings Ltd | Real estate | 2025 |
| Skypay Travel Ltd | Administrative & support | 2025 |
| Skyscrapers Holdings Ltd | Real estate | 2021 |
| Skyscrapers Trading Limited | Wholesale & retail | 2025 |
| Skyward Homes Ltd | Real estate | 2023 |
| SL Agency Ltd | Professional & scientific | 2020 |
| Sleek Data Limited | Information & communication | 2023 |
| Sljb Limited | Education | 2022 |
| Slmg Limited | Construction | 2016 |
| SM 22 ZUZ Limited | Construction | 2022 |
| SM Khan Limited | Real estate | 2021 |
| SM Strategy Ltd | Real estate | 2020 |
| SM4 Design and Build Ltd | Construction | 2026 |
| SMA Xpert IT Solutions Ltd | Information & communication | 2023 |
| Small Holland Ltd | Arts & recreation | 2015 |
| Smart Auto Gate Ltd | Construction | 2019 |
| Smart Build Contracts Ltd | Construction | 2022 |
| Smart Energie Limited | Construction | 2022 |
| Smart Epos LDN Ltd | Information & communication | 2025 |
| Smart FNF Investments Ltd | Real estate | 2024 |
| Smart Investments & Construction Ltd | Real estate | 2013 |
| Smart Leap 360 Ltd | Professional & scientific | 2025 |
| Smart Plex Limited | Administrative & support | 2020 |
| Smart Retrofit Skills Ltd | Education | 2026 |
| Smart Sweep Group Ltd | Transport & logistics | 2025 |
| Smart Wiring Ltd | Information & communication | 2015 |
| Smarter Production Ltd | Wholesale & retail | 2024 |
| Smartronics Ltd | Administrative & support | 2022 |
| Smash Nutrition Ltd | Manufacturing | 2015 |
| Smgltd Ltd | Information & communication | 2014 |
| Smile (UK) Limited | Administrative & support | 2013 |
| Smiles by Arti Ltd | Health & social care | 2021 |
| Snapwise Solution Limited | Information & communication | 2024 |
| Snooze London Ltd | Wholesale & retail | 2025 |
| Snrcontractors Ltd | Construction | 2023 |
| Sobber Ltd | Wholesale & retail | 2025 |
| Sobeh Management Limited | Real estate | 2013 |
| Social Care Interventions (SCI) Ltd | Health & social care | 2016 |
| Sofi Rich Ltd | Manufacturing | 2024 |
| Sofia Building Management Ltd | Real estate | 2024 |
| Softforce Limited | Information & communication | 2020 |
| Sohal GAS Solutions Ltd | Energy | 2022 |
| Sohir Beauty & Aesthetics Ltd | Other services | 2025 |
| Soilcandy Ltd | Wholesale & retail | 2020 |
| Sojski Travel Ltd | Transport & logistics | 2023 |
| SOL Fragrances Limited | Wholesale & retail | 2020 |
| SOL Motion Foundation | Professional & scientific | 2024 |
| SOL Motion Pictures Limited | Information & communication | 2010 |
| Solarmise Limited | Construction | 2023 |
| Solas Anam Ltd | Administrative & support | 2011 |
| Solis House Limited | Construction | 2007 |
| Solutions and Build Ltd | Construction | 2015 |
| Somasundaram Consulting Limited | Administrative & support | 2014 |
| Something Country Limited | Wholesale & retail | 2012 |
| Son&Y Security Company Ltd | Administrative & support | 2021 |
| Sonwadi Ltd | Wholesale & retail | 2022 |
| Sony Construction Services Limited | Other services | 2017 |
| Sool Schools Ltd | Other services | 2017 |
| Soren Estate Ltd Ltd | Real estate | 2026 |
| Sotobud Ltd | Construction | 2019 |
| Source-It MAX Ltd | Wholesale & retail | 2023 |