| Salamis Trading Limited | Real estate | 1997 |
| Saleem Ventures Ltd | Real estate | 2019 |
| Salem (UK) Limited | Construction | 2013 |
| Sales Alive Ltd | Wholesale & retail | 2015 |
| Salesbuzz'Ter UK Ltd | Professional & scientific | 2016 |
| Salientwork Ltd | Professional & scientific | 2012 |
| Salisbury Consulting Limited | Professional & scientific | 2014 |
| Salixrasr Ltd | Manufacturing | 2021 |
| Salkeld & SON Property Ltd | Real estate | 2023 |
| Salkeld & SON Property Services Ltd | Real estate | 2019 |
| Sallust Trading LLP | | 2022 |
| Salon Bowie Limited | Information & communication | 2016 |
| Salon DE Beauté Ltd | Other services | 2024 |
| Salon Grand Limited | Information & communication | 2018 |
| Salon of Gems Limited | Other services | 2024 |
| Salsecurity Ltd | Information & communication | 2024 |
| Salteck Capital Limited | Professional & scientific | 2013 |
| Salvatore Property Developments Limited | Construction | 2011 |
| Salvei & Sean Ltd | Wholesale & retail | 2022 |
| SAM Delight Limited | Hospitality | 2025 |
| SAM Denmark Art Limited | Arts & recreation | 2019 |
| SAM Mancey Coaching & Consulting Ltd | Administrative & support | 2022 |
| SAM Murray Creative Ltd | Professional & scientific | 2023 |
| Samanthaworks Ltd | Professional & scientific | 2025 |
| Samite Consulting Ltd | Professional & scientific | 2018 |
| Samuel Palmer Limited | Financial services | 2018 |
| Samz Care Ltd | Health & social care | 2022 |
| SAN Antonio Ltd | Hospitality | 2018 |
| Sanam Property Services Ltd | Real estate | 2012 |
| Sanawar Limited | Households | 2007 |
| Sanders Archer Architects Ltd | Professional & scientific | 2026 |
| Sandpit Coaching Ltd | Education | 2024 |
| Sandra Hilton Therapy Ltd | Health & social care | 2021 |
| Sandridge E&P Consulting Limited | Professional & scientific | 2023 |
| Sandstone Films Limited | Information & communication | 2013 |
| SANDY2025 Limited | Extraterritorial | 2025 |
| Sanganak Services Limited | Information & communication | 2010 |
| Santofogo Ventures SPV LLP | | 2021 |
| Sapperz Limited | Wholesale & retail | 2025 |
| Sapphic Nights Limited | Hospitality | 2025 |
| Sapphire Health Connect Ltd | Health & social care | 2023 |
| Sapphire Skies Limited | Professional & scientific | 2016 |
| Saradjola Photography Ltd | Professional & scientific | 2021 |
| Sarah Jones Communications Ltd | Professional & scientific | 2011 |
| Saras Capital Co-Invest II LLP | | 2022 |
| Sardo Furiosu Limited | Manufacturing | 2025 |
| Sarff - Dacre Limited | Construction | 2017 |
| Sarr Hotels (Luton) Ltd | Hospitality | 2016 |
| Sarr Hotels Limited | Hospitality | 2015 |
| Sarr Hotels Noke Limited | Hospitality | 2016 |
| Sarr Investments Limited | Hospitality | 2015 |
| Sarr Management Ltd | Administrative & support | 2017 |
| Sarr Noke Hospitality Limited | Hospitality | 2016 |
| Sarros Consulting Limited | Professional & scientific | 2022 |
| Sarumi Estates Ltd | Real estate | 2025 |
| SAS Timber Ltd | Manufacturing | 2025 |
| Sasa Arts Ltd | Education | 2018 |
| Sasa's Youth Programme (SYP) CIC | Other services | 2021 |
| Sash Restoration London Limited | Construction | 2019 |
| Sasm Limited | Real estate | 2017 |
| Satgana FI SPV LP | | 2021 |
| SAU SAV Property Holdings Limited | Real estate | 2019 |
| Saute Restaurant Ltd | Hospitality | 2017 |
| Save ST Albans Pubs Ltd | Hospitality | 2021 |
| Save ST Albans: Fight the Freight CIC | Other services | 2023 |
| Saverplaces Limited | Professional & scientific | 2014 |
| Savi Services Limited | Professional & scientific | 2015 |
| Savinvest Consulting Praxis Limited | Information & communication | 2013 |
| Saxby Group Ltd | Professional & scientific | 2024 |
| SB & AB Limited | Manufacturing | 1980 |
| SBH Consultancy Limited | Professional & scientific | 2025 |
| Sboh Limited | Construction | 2021 |
| SC1 Consultancy Ltd | Professional & scientific | 2018 |
| Scale by Design Ltd | Professional & scientific | 2026 |
| Scale-Up Advisors Limited | Administrative & support | 2020 |
| Scales Cleaning Service Ltd | Administrative & support | 2023 |
| Scalpel Property Ventures Ltd | Real estate | 2023 |
| Scarbo Group Ltd | Construction | 2025 |
| Scared Crow Limited | Hospitality | 2004 |
| Scarlett London Digital Limited | Information & communication | 2016 |
| Scary Robots Limited | Information & communication | 2025 |
| Schields Ltd | Professional & scientific | 2020 |
| Schnu Property Limited | Real estate | 2008 |
| School Support People Ltd | Education | 2019 |
| Science Atomic UK Community Interest Company | Education | 2016 |
| Science Innovation Limited | Information & communication | 2004 |
| Science Rocks UK Limited | Education | 2016 |
| Sciencemagic.Inc Limited | Professional & scientific | 2003 |
| Scientialis Ltd | Professional & scientific | 2013 |
| Scientific UP Limited | Professional & scientific | 2016 |
| Scion Digital Ltd | Information & communication | 2011 |
| Scnc Ltd | Extraterritorial | 2024 |
| Scondrianis Aero Limited | Manufacturing | 2024 |
| Scope Office Search Limited | Real estate | 2025 |
| Scotchport Project Services Ltd | Professional & scientific | 2023 |
| Scott Audio Visual Ltd | Wholesale & retail | 2005 |
| Scott James Renovations Ltd | Construction | 2025 |
| Scott Landscaping Services Limited | Administrative & support | 2011 |
| Scott Lane Developments Ltd | Real estate | 2023 |
| Scott Whitehead Ltd | Hospitality | 2023 |