| Scottsdale Capital Limited | Extraterritorial | 2010 |
| Scottsdale Moneywise Limited | Extraterritorial | 2013 |
| SCP OPS LLP | | 2022 |
| SCR Medical Ltd | Administrative & support | 2011 |
| Scribe Publisher Services Inc. | | 1984 |
| Scrufts Grooming Ltd | Extraterritorial | 2021 |
| SCW Consulting Ltd | Professional & scientific | 2024 |
| SDA Apartments Ltd | Real estate | 2014 |
| SDB Clean Ltd | Administrative & support | 2026 |
| Sea Tech Offshore Limited | Professional & scientific | 2011 |
| Seaford West Limited | Households | 2016 |
| Seagrove Bay Investments Limited | Administrative & support | 2020 |
| Seai Solutions Ltd | Wholesale & retail | 2025 |
| Seal Outdoor Swimming Limited | Manufacturing | 2020 |
| Search and Supply Ltd | Energy | 2019 |
| Search Informer Ltd | Professional & scientific | 2026 |
| Sears Brothers Electrical Services Ltd | Construction | 2016 |
| Seaura Properties Ltd | Real estate | 2025 |
| Sebright Advisors Ltd | Professional & scientific | 2026 |
| Security Matters Limited | Administrative & support | 1995 |
| Sedulous Procurement Solutions Ltd | Administrative & support | 2021 |
| SEE Taylor Construction Ltd | Construction | 2026 |
| Seesea Ltd | Professional & scientific | 2021 |
| Seewoo (Reading) Limited | Wholesale & retail | 2003 |
| SEG Wifi Limited | Information & communication | 2026 |
| Segsbury Limited | Arts & recreation | 1994 |
| Selby Productions Ltd | Information & communication | 2024 |
| Select Group (2024) Ltd | Administrative & support | 2023 |
| Select Pharma Limited | Administrative & support | 2024 |
| Self Management UK Limited | Health & social care | 2012 |
| Sell Sell Limited | Professional & scientific | 2005 |
| Selsby Consulting Limited | Professional & scientific | 2009 |
| Selsby Property 1 Limited | Real estate | 2009 |
| Selsleyview Limited | Professional & scientific | 2012 |
| Semantia Ltd | Professional & scientific | 2024 |
| Semantic Ventures GP Limited | Financial services | 2018 |
| Semantic Ventures I LP | | 2018 |
| Semantic Ventures II GP Limited | Financial services | 2022 |
| Semantic Ventures II LP | | 2022 |
| Semantic Ventures II Second GP LLP | | 2022 |
| Semantic Ventures LLP | | 2018 |
| Semantic Ventures Second GP LLP | | 2018 |
| Semazen Ltd | Hospitality | 2015 |
| Semper SPV 1 LLP | | 2021 |
| Senc Ltd | Administrative & support | 2019 |
| Send and Neurodiversity Solutions Ltd | Professional & scientific | 2026 |
| Sendhelp Education Limited | Education | 2025 |
| Sendhelp School (Buckingham) Limited | Education | 2026 |
| Sendhelp Social Care Limited | Health & social care | 2026 |
| Senior Media Ltd | Information & communication | 2026 |
| Senkao Ltd | Wholesale & retail | 2023 |
| Sentient Ventures I LP | | 2022 |
| Sentri Strategy Ltd | Professional & scientific | 2024 |
| Senzo Tanaka Ltd | Hospitality | 2018 |
| September Alton Limited | Real estate | 2022 |
| Serenity Hygiene Ltd | Manufacturing | 2015 |
| Serenity Management Solutions Limited | Health & social care | 2026 |
| Service Logic Limited | Manufacturing | 1999 |
| Service Reach Limited | Administrative & support | 2022 |
| Services Trading Research Industrial Distribution Expertise Limited | Wholesale & retail | 2017 |
| Servitol UK Ltd | Professional & scientific | 2020 |
| Session Solutions Ltd | Professional & scientific | 2019 |
| Sesto.Ai Limited | Professional & scientific | 2025 |
| Setnix Ltd | Wholesale & retail | 2023 |
| Sevan International Ltd | Extraterritorial | 2024 |
| Sevenaxservices Ltd | Water & waste | 2026 |
| Severn Clinical Group Limited | Health & social care | 2022 |
| Severn Hospital Limited | Health & social care | 2023 |
| Severnside Distribution Park (Bristol) Management Limited | Real estate | 1996 |
| Seymour Insight Limited | Professional & scientific | 2015 |
| Seymour Place Consulting Limited | Professional & scientific | 2023 |
| Sfaitzer Ltd | Manufacturing | 2021 |
| SFK Apartments Ltd | Hospitality | 2022 |
| SFM Technology Limited | Manufacturing | 1985 |
| SG Luxury Design Limited | Wholesale & retail | 2016 |
| SG Property Portfolio Limited | Real estate | 2022 |
| SG Technology Services Ltd | Manufacturing | 2021 |
| SGE UK Group Limited | Financial services | 2022 |
| Sgsa Limited | Information & communication | 2007 |
| Sgslg Limited | Education | 2009 |
| SH Accountants Ltd | Professional & scientific | 2026 |
| SH Billing Limited | Professional & scientific | 2006 |
| Shaca Construction Limited | Construction | 2002 |
| Shaca Steel Limited | Construction | 2018 |
| Shaheen Express Removals Limited | Manufacturing | 2023 |
| Shakarainc Limited | Wholesale & retail | 2020 |
| Shal Properties Ltd | Real estate | 2021 |
| Shamily Ltd | Wholesale & retail | 2025 |
| Shapla ST Albans Ltd | Hospitality | 2023 |
| SHAREFORCE360 Limited | Information & communication | 2022 |
| Sharpentry Ltd | Construction | 2025 |
| Sharper Labs HR and Legal Consultancy Ltd | Professional & scientific | 2020 |
| Sharpsurge Limited | Information & communication | 1988 |
| Sharrow Bay Properties Limited | Hospitality | 2012 |
| Shaw Consultancy Limited | Professional & scientific | 2006 |
| Shaw Financial London Limited | Administrative & support | 2016 |
| Shaw Professional Limited | Real estate | 2013 |
| SHE Leads Collective Ltd | Other services | 2025 |
| SHE Writes Media Ltd | Public administration | 2023 |
| Sheard Consulting Limited | Other services | 2010 |