| Saint Limited | Professional & scientific | 2015 |
| Salani UK Ltd | Wholesale & retail | 2026 |
| Salisbury Technology Services Ltd | Information & communication | 2017 |
| Salmon Land Company Limited | Professional & scientific | 2017 |
| SAM Littlewood Limited | Professional & scientific | 2026 |
| SAM Redman Consulting Limited | Professional & scientific | 2019 |
| SAM Rudd Coaching Ltd | Construction | 2022 |
| Samville Ltd | Financial services | 2020 |
| Sancia Ltd | Professional & scientific | 2024 |
| Sansom KP Ltd | Health & social care | 2023 |
| Sapd Global Limited | Wholesale & retail | 2009 |
| Sapphire Cleaning Company Ltd | Administrative & support | 2022 |
| Sapphire Gymnastics CIC | Arts & recreation | 2013 |
| Sapphire School of Gymnastics Limited | Arts & recreation | 2007 |
| Sarah Vaux Limited | Administrative & support | 2010 |
| Saviac Design Limited | Professional & scientific | 2013 |
| Saxon Enterprises LLP | | 2023 |
| SAY IT Again, Sorry? Ltd | Arts & recreation | 2019 |
| SBA Consulting Services Limited | Professional & scientific | 2019 |
| Sbuckland Property Ltd | Real estate | 2025 |
| Scarlets Enterprises Limited | Hospitality | 2019 |
| Scenic 2 Decor Limited | Information & communication | 2009 |
| Scenic Woods Ltd | Construction | 2022 |
| Schnapps Takk Limited | Hospitality | 2019 |
| SCI Partners LLP | | 2012 |
| Sculptural Properties Limited | Real estate | 1982 |
| Seaglass Properties Ltd | Hospitality | 2020 |
| Seasoft Limited | Information & communication | 2018 |
| Seaview Crescent Amenities Limited | Real estate | 2005 |
| Selenium Consultancy Limited | Information & communication | 2019 |
| Senior Partners Limited | Hospitality | 2018 |
| Sensory Beginnings Ltd | Education | 2019 |
| Sentido Consulting Limited | Professional & scientific | 2007 |
| Sequel Epic Ltd | Information & communication | 2021 |
| Serene Spa Limited | Other services | 2007 |
| Service DE Course Ltd | Wholesale & retail | 2019 |
| SET 2 Sail Limited | Manufacturing | 2019 |
| Setaway Limited | Transport & logistics | 2022 |
| Seven D Solutions Limited | Construction | 2024 |
| Sevenday Takeaway Ltd | Wholesale & retail | 2026 |
| Sevenoaks Financial Ltd | Professional & scientific | 2026 |
| SGM Construction Design and Build Ltd | Construction | 2024 |
| SGT Events Ltd | Administrative & support | 2025 |
| SH Concepts Ltd | Professional & scientific | 2021 |
| SH Procure Ltd | Professional & scientific | 2023 |
| Share Alliance | Professional & scientific | 2022 |
| Share Premium Ltd | Information & communication | 2016 |
| Shareholder Limited(The) | Professional & scientific | 1987 |
| Sharon Preston Consulting Ltd | Professional & scientific | 2025 |
| Shearer Van DER Burgh Ltd | Construction | 2012 |
| Shek Investment Partners Limited | Financial services | 2019 |
| Sher Consulting Limited | Information & communication | 2010 |
| Shopworks Investments Limited | Real estate | 2021 |
| Shopworks Ltd | Professional & scientific | 1997 |
| Shree SAI Venkatesh Consultancy Ltd | Information & communication | 2023 |
| Sigma Delta Holdings Limited | Information & communication | 2023 |
| Silk Mill Leisure Limited | Real estate | 2017 |
| Silverthorn Wealth Management Limited | Financial services | 2014 |
| Simari Solutions Limited | Administrative & support | 2021 |
| Simple Tech Results Ltd | Information & communication | 2014 |
| Simport Limited | Wholesale & retail | 2010 |
| Sinfield Services Limited | Construction | 2016 |
| Singh Agile Content Design Limited | Information & communication | 2017 |
| Singlefox Limited | Extraterritorial | 2012 |
| Singleton & Faringdon Group Ltd | Real estate | 2025 |
| Sinha ROY Solutions Limited | Information & communication | 2013 |
| Sinmac Health and Care Management Limited | Public administration | 2022 |
| SIR Frederick Alban Trust Limited | Financial services | 2002 |
| Sivart Limited | Information & communication | 2017 |
| SIX Pillars Consultancy Limited | Professional & scientific | 2025 |
| SIX4SIX Ltd | Arts & recreation | 2010 |
| Sixfeetfour Limited | Information & communication | 2017 |
| SJ Auto Doctors Ltd | Wholesale & retail | 2014 |
| SJG Electrical Services Ltd | Construction | 2014 |
| SJP Technology Limited | Information & communication | 2023 |
| SK ERP Solutions Ltd | Information & communication | 2023 |
| SK Veterinary Services Ltd | Wholesale & retail | 2019 |
| Skadi Limited | Professional & scientific | 2012 |
| Skeertech Ltd | Manufacturing | 2019 |
| Skiio Ltd | Wholesale & retail | 2024 |
| Skipton Strategy Ltd | Professional & scientific | 2024 |
| Sky Alliance International Investment (UK) Limited | Financial services | 2017 |
| Skyswan Ltd | Information & communication | 2024 |
| Slam Photography Limited | Professional & scientific | 2002 |
| SLB London Ltd | Construction | 2018 |
| SLN Transport Ltd | Transport & logistics | 2014 |
| SM Flooring (Bucks) Limited | Construction | 2021 |
| Smallworks Scaffolding (Leighton Buzzard) Ltd | Construction | 2014 |
| Smartcare Medical Limited | Professional & scientific | 2011 |
| Smartcare Technologies Limited | Extraterritorial | 2011 |
| Smartcare Worldwide Limited | Professional & scientific | 2011 |
| SME Advantage Ltd | Information & communication | 2021 |
| Smiddy & Co Limited | Administrative & support | 2003 |
| Smilernet Limited | Information & communication | 2018 |
| Smwiksoft Ltd | Information & communication | 2024 |
| Snappy CGI Ltd | Arts & recreation | 2016 |
| Snowsense Ltd | Information & communication | 2025 |
| Soleil Levant Limited | Financial services | 2024 |
| Solid State Technologies Ltd | Information & communication | 2020 |
| Somersault Cloud Ltd | Professional & scientific | 2020 |