| Spring Resourcing Solutions Ltd | Administrative & support | 2023 |
| Spring Treasure | Health & social care | 2019 |
| Spring Valley View (Clayton) Management Company Limited | Households | 2018 |
| Springer Rock Hotel Operations Limited | Hospitality | 2022 |
| Springer Rock Joint Ventures Ltd Ltd | Hospitality | 2023 |
| Springer Rock Property Holdings Limited | Hospitality | 2022 |
| Sprint Runners Ltd | Transport & logistics | 2018 |
| Spydersecurity Limited | Administrative & support | 2012 |
| Square Pixel Productions Limited | Information & communication | 2016 |
| Square Root People Limited | Extraterritorial | 2016 |
| Squared Property Limited | Real estate | 2022 |
| Squared Two Property Limited | Real estate | 2025 |
| Squareplus Design Ltd | Professional & scientific | 2018 |
| Squirrels Day Nurseries (Broxbourne) Ltd | Education | 2001 |
| Squirrels Day Nurseries (Hatfield) Ltd | Education | 2012 |
| Squirrels Day Nurseries (Hemel) Ltd | Education | 2012 |
| Squirrels Day Nurseries (Watford) Ltd | Education | 2012 |
| Squirrels Day Nurseries (Welwyn) CIC | Education | 2002 |
| Squirrels Day Nurseries Ltd | Education | 2012 |
| Squirrels Day Nursery Ltd | Education | 2012 |
| Sraheja Ltd | Information & communication | 2011 |
| SRI Lanka Schools Touch Rugby UK Ltd | Arts & recreation | 2024 |
| SRI Sahasra Global Careers UK Ltd | Professional & scientific | 2025 |
| SRS SCO Ltd | Real estate | 2025 |
| SRS Specialist Contractors Limited | Construction | 2010 |
| SRT Scaffolding & Rigging Ltd | Construction | 2024 |
| SSD Drives Limited | Extraterritorial | 1974 |
| Ssei Equity Ltd | Financial services | 2021 |
| SSG Group Limited | Real estate | 2023 |
| SSG Partners 22 Ltd | Administrative & support | 2026 |
| SSG Partners 23 Ltd | Administrative & support | 2026 |
| SSG Partners 24 Ltd | Administrative & support | 2026 |
| SSG Partners 25 Ltd | Administrative & support | 2026 |
| SSG Partners 26 Ltd | Administrative & support | 2026 |
| SSG Partnerships Ltd | Extraterritorial | 2022 |
| SSG Recruitment Partnerships Ltd | Professional & scientific | 2003 |
| SSG Ventures Ltd | Extraterritorial | 2022 |
| SSH Housing Ltd | Real estate | 2025 |
| Ssjw Ltd | Real estate | 2026 |
| Sskgs Holdings Limited | Real estate | 2022 |
| Sskgs Trading Limited | Wholesale & retail | 2022 |
| SSN Learning Tree Limited | Education | 2026 |
| Ssrk Supermarket Ltd | Wholesale & retail | 2024 |
| SSS Public Safety Limited | Information & communication | 2020 |
| ST Albans Building & Plastering Ltd | Construction | 2015 |
| ST Ann's Mews Management Company Limited | Households | 2008 |
| ST Chamberlin Marketing Ltd | Wholesale & retail | 2025 |
| ST Fulfillment Services Ltd | Transport & logistics | 2024 |
| ST George's Park (Phase 2) Management Company Limited | Households | 2021 |
| ST George's Park Management Company Limited | Households | 2019 |
| ST Hilds Management Company Limited | Households | 2003 |
| ST Ives Bay Holiday Park Ltd | Hospitality | 2021 |
| ST James Property Developments (UK) Ltd | Real estate | 2004 |
| ST Martins Court (Ruislip) Residents Management Company Limited | Households | 2007 |
| ST Nicholas Mews Basildon Management Company Limited | Households | 2016 |
| Stack Temporary Boiler Hire Ltd | Administrative & support | 2026 |
| Staffmis Limited | Information & communication | 2005 |
| Stag Edition Ltd | Wholesale & retail | 2009 |
| Stag RTM Company Limited | Households | 2009 |
| Stage 5 Properties Ltd | Construction | 2022 |
| Stage Left Construction Limited | Construction | 2021 |
| Stage Source Ltd | Other services | 2018 |
| Stage Two Limited | Administrative & support | 1979 |
| Stags END Props Limited | Administrative & support | 2021 |
| Stain Hunters Ltd | Administrative & support | 2024 |
| Stal Transport Ltd | Transport & logistics | 2026 |
| Stalif Solutions CIC | Health & social care | 2021 |
| Stallion Recruitment Limited | Administrative & support | 2012 |
| Stamfordco Ltd | Construction | 2019 |
| Stana Dorului Ltd | Wholesale & retail | 2022 |
| Standard 8 Recruitment Ltd | Administrative & support | 2025 |
| Standard Nursing Agency and Care Services Limited | Health & social care | 2009 |
| Stanford Hart Limited | Construction | 2025 |
| Stanham Close Wombourne (Management Company) Limited | Households | 2011 |
| Stanley & Beau Ltd | Construction | 2013 |
| Stanley Road (Great Chesterford) Management Company Limited | Households | 2014 |
| Stansell Investments Ltd | Real estate | 2025 |
| Star Dental Care Limited | Health & social care | 2014 |
| Star Trans Total Ltd | Transport & logistics | 2017 |
| Starfillpack Ltd | Administrative & support | 2023 |
| Starla Properties Ltd | Real estate | 2023 |
| Starlink Express Ltd | Transport & logistics | 2022 |
| Stars Drive Ltd | Wholesale & retail | 2021 |
| Starx Accounting Limited | Professional & scientific | 2021 |
| Stashic Ltd | Wholesale & retail | 2019 |
| Stateline Bearings & Transmission Limited | Wholesale & retail | 2001 |
| Station Road (Barnet) Management Company Limited | Households | 1986 |
| Station Road (New Barnet) Freehold Limited | Households | 2005 |
| Statmap Ltd | Information & communication | 2008 |
| Statmap Properties Ltd | Real estate | 2022 |
| Stay Human Limited | Information & communication | 2024 |
| Stay Sharp Turf Care Limited | Manufacturing | 2007 |
| Steadfast Systems Ltd | Administrative & support | 2018 |
| Stebbing Management Company Ltd | Households | 2018 |
| Steel Blue Structures Ltd | Real estate | 2024 |
| Steel Optical Limited | Health & social care | 2019 |
| Steers & SON Building Services Ltd | Construction | 2015 |
| Steffan Construction Limited | Construction | 2015 |
| Stella Giorgi Ltd | Professional & scientific | 2026 |
| Stemcell Ltd | Information & communication | 2023 |