| Salutem LD Bidco Limited | Health & social care | 2017 |
| Salutem LD Midco I Limited | Health & social care | 2022 |
| Salutem LD Midco II Limited | Health & social care | 2022 |
| Salutem LD Topco II Limited | Health & social care | 2018 |
| Salutem LD Topco Limited | Health & social care | 2017 |
| Salutem Shared Services II Limited | Health & social care | 2019 |
| Salutem Shared Services III Limited | Health & social care | 2019 |
| Salutem Shared Services Limited | Administrative & support | 2018 |
| SAM at Signature Travel Ltd | Administrative & support | 2025 |
| SAM Residential Limited | Construction | 2023 |
| Sami BTL Ltd | Real estate | 2021 |
| Sampson Management Ltd | Professional & scientific | 2019 |
| Samuel James Property Investments Ltd | Real estate | 2025 |
| SAN Lorenzo AJ Ltd | Hospitality | 2025 |
| Sanbei-Uk Ltd | Wholesale & retail | 2010 |
| Sancto Homes Ltd | Real estate | 2021 |
| Sandford Electrical Services Limited | Construction | 1989 |
| Sandhill Partners Ltd | Education | 2019 |
| Sangra Haulage Limited | Transport & logistics | 2016 |
| Sangria 3 Limited | Real estate | 2016 |
| Sant Kishan Singh Supermarket Limited | Wholesale & retail | 2002 |
| Santel Industries Limited | Professional & scientific | 2010 |
| Santokh Property Limited | Real estate | 2019 |
| Sapienai Limited | Professional & scientific | 2026 |
| Sask Surgicare Ltd | Health & social care | 2024 |
| Sath Distribution Limited | Wholesale & retail | 2019 |
| Satluj Limited | Wholesale & retail | 2014 |
| Saul Pearce Consulting Ltd | Professional & scientific | 2021 |
| Saunders & Long Limited | Wholesale & retail | 2016 |
| Savin Communications Limited | Information & communication | 2005 |
| Savin Group Asset Management Limited | Real estate | 2024 |
| Savin Technology Group Ltd | Administrative & support | 2011 |
| Savvy Mortgages Limited | Financial services | 2015 |
| Sawan Holdings Limited | Financial services | 2019 |
| Sayat Company Ltd | Administrative & support | 2013 |
| SB Fleet Assistance Limited | Wholesale & retail | 2022 |
| SB Industries Ltd | Transport & logistics | 2025 |
| SB Medical Training Ltd | Public administration | 2022 |
| SB One Four Ltd | Wholesale & retail | 2026 |
| SB Relocations Limited | Real estate | 2021 |
| SB Walls & More Ltd | Real estate | 2020 |
| SC Goods Ltd | Wholesale & retail | 2022 |
| SC Leisure Group Limited | Other services | 1960 |
| SCA UK Chapter Ltd | Other services | 2020 |
| Scailr Limited | Information & communication | 2025 |
| Scarecrow Marketing Limited | Professional & scientific | 2009 |
| Scarlett OH Limited | Professional & scientific | 2006 |
| SCB Executive Coaching Ltd | Professional & scientific | 2023 |
| SCC Valeting Ltd | Administrative & support | 2021 |
| SCH Landprop Ltd | Real estate | 2024 |
| Scholars Rise (Stokenchurch) Management Company Limited | Households | 2015 |
| School Solutions Ltd | Administrative & support | 2024 |
| Schools Management Limited | Administrative & support | 2016 |
| Scio Ltd | Information & communication | 2013 |
| SCOFS3HOLDINGS Ltd | Real estate | 2025 |
| Scotton's Holdings Ltd | Financial services | 2022 |
| Scout Kids Limited | Information & communication | 2025 |
| Scream Pretty Limited | Extraterritorial | 2014 |
| Scrumys Group Ltd | Education | 2022 |
| Sculptlite Limited | Professional & scientific | 2013 |
| SDS & Sons Ltd | Manufacturing | 2024 |
| SDS Landscaping Limited | Administrative & support | 2022 |
| SDX Holding Limited | Information & communication | 2023 |
| Sea Dream Consulting Limited | Professional & scientific | 2021 |
| Seagull Safety Limited | Other services | 1989 |
| Seal Pro Roofing Ltd | Construction | 2024 |
| Seasoned Ltd | Hospitality | 2021 |
| Sebastian Ford Hairdressing Ltd. | Other services | 2020 |
| Sebastian's Italian Limited | Hospitality | 2013 |
| Sebel Interiors Limited | Extraterritorial | 2019 |
| Seckr Technology Ltd | Information & communication | 2024 |
| Secure by Design Group Limited | Information & communication | 2022 |
| Secure Roofing & Landscaping Ltd | Construction | 2025 |
| Secureplace Property Management Limited | Households | 1986 |
| Sehgal Stores Ltd | Wholesale & retail | 2015 |
| Sekhon Property Services Ltd | Real estate | 2025 |
| Seko Logistics (London) Limited | Transport & logistics | 2002 |
| Seko Logistics (North) Limited | Transport & logistics | 2014 |
| Seko Logistics (Southampton) Limited | Transport & logistics | 2013 |
| Seko Logistics EU Group, Ltd. | Administrative & support | 2022 |
| Seko Logistics Group Limited | Administrative & support | 2013 |
| Seko Logistics Scotland Limited | Administrative & support | 2009 |
| Seko Logistics Solutions Limited | Administrative & support | 2011 |
| Seko Omni-Channel Logistics Limited | Administrative & support | 2013 |
| SEL ET Sucre Ltd | Hospitality | 2024 |
| Select Italy & Travel Limited | Administrative & support | 2014 |
| Sensura (UK) Limited | Health & social care | 2011 |
| Sensura Holdings Limited | Health & social care | 2014 |
| Sentasia Ltd | Information & communication | 2025 |
| Sente Properties Ltd | Real estate | 2021 |
| SEO & Design Ltd | Information & communication | 2016 |
| Seraphim Consort Ltd | Arts & recreation | 2016 |
| Serene Ltd | Professional & scientific | 2026 |
| Serika (EA) Limited | Construction | 2010 |
| Servify Plus Ltd | Information & communication | 2024 |
| Setsofran London Limited | Wholesale & retail | 2022 |
| Settled Group Limited | Financial services | 2024 |
| Seven Eight Asset Limited | Extraterritorial | 2008 |
| Seven Oaks Hospitality Ltd | Hospitality | 2025 |
| Seven Seas Auto Limited | Mining & quarrying | 2021 |