| Smarter Logistics Limited | Transport & logistics | 2023 |
| Smarter Vision Limited | Information & communication | 1998 |
| Smarts Interiors Ltd | Construction | 2026 |
| Smash Shack Burgers Limited | Hospitality | 2025 |
| SME 83 Ltd | Professional & scientific | 2019 |
| SME Magazine Limited | Information & communication | 2017 |
| Smex Holdings Limited | Real estate | 2020 |
| SMF Hair Replacement Limited | Other services | 2025 |
| Smile Craft Studio Limited | Health & social care | 2014 |
| Smiles (MB) Limited | Health & social care | 2015 |
| Smiles Electrical Solutions Ltd | Construction | 2026 |
| Smills Holdings Ltd | Financial services | 2025 |
| Smith & Ellis Ltd | Manufacturing | 2017 |
| Smiths Business Supplies Ltd | Wholesale & retail | 2023 |
| SML Warehouse Services Ltd | Manufacturing | 2022 |
| SNA Builders Limited | Construction | 2011 |
| Snap Grip Limited | Wholesale & retail | 2022 |
| Snowberry Limited | Professional & scientific | 2025 |
| Snowbridge Consulting Limited | Professional & scientific | 2014 |
| Snowcompare Limited | Administrative & support | 2016 |
| Snowdon Investments Limited | Real estate | 2008 |
| SNS Stock Solutions Limited | Wholesale & retail | 2021 |
| Soak and Glow Essentials Ltd | Wholesale & retail | 2025 |
| Softday Ltd | Wholesale & retail | 2025 |
| Software 24 Ltd | Information & communication | 2024 |
| Solace Mortgages Limited | Financial services | 2025 |
| Solan Engineering Ltd | Professional & scientific | 2022 |
| Solely Cremation Limited | Other services | 2019 |
| Solitaire Doors Limited | Construction | 2024 |
| Solo Carpets Limited | Wholesale & retail | 1994 |
| Solo's Beers Limited | Hospitality | 2023 |
| Solor Care (South West) Ltd | Health & social care | 2001 |
| Solor Care Group Limited | Health & social care | 2001 |
| Solor Care Holdings (2) Ltd | Professional & scientific | 2001 |
| Solor Care Holdings (3) Ltd | Health & social care | 1994 |
| Solor Care London Ltd | Health & social care | 1997 |
| Solor Care Ltd | Health & social care | 1989 |
| Solor Care South East (2) Ltd | Health & social care | 1990 |
| Solor Care South East Ltd | Health & social care | 1990 |
| Solor Care West Midlands Ltd | Health & social care | 2001 |
| Somerfield & Co Limited | Professional & scientific | 2013 |
| Somervills Ltd | Hospitality | 2025 |
| Something Classy Presentation Packaging Ltd | Wholesale & retail | 2014 |
| Sorrel Commercial Properties Limited | Real estate | 1988 |
| Sorrel Properties Limited | Real estate | 2000 |
| Sorrel Property Holdings Limited | Other services | 2008 |
| Sorrell Beauty Limited | Health & social care | 2019 |
| Sospa@Somervills Limited | Hospitality | 2025 |
| Sound Logic Limited | Information & communication | 2000 |
| Sour Foundry Ltd | Manufacturing | 2026 |
| Source Business Finance Ltd | Financial services | 2020 |
| South Acres Storage Ltd | Administrative & support | 2026 |
| South Mill Country Homes Limited | Construction | 2001 |
| South Staffordshire Freight Services Limited | Real estate | 1987 |
| South Staffs Freight Limited | Financial services | 2023 |
| South Staffs Freight Terminal Limited | Wholesale & retail | 1996 |
| South Yorkshire Construction Limited | Construction | 2025 |
| Southall Harries and Associates Ltd | Financial services | 2012 |
| Southall Harries Limited | Financial services | 2006 |
| Southbank Building Ltd | Construction | 2011 |
| Southbank Design & Build Limited | Construction | 2023 |
| Southbank Homes Midlands Limited | Construction | 2023 |
| Southwestern Corporation UK Limited | Professional & scientific | 2001 |
| Southwestern Engineering Limited | Manufacturing | 2008 |
| Sovereign Coldrooms Limited | Manufacturing | 2019 |
| Sovereign Group Holdings Limited | Financial services | 2020 |
| Sovereign Mechanical and Fabrication Service Limited | Professional & scientific | 2012 |
| Sovereign Refrigeration Limited | Manufacturing | 1985 |
| Sovereign Renewables Limited | Construction | 2021 |
| Sovereon Ltd | Information & communication | 2026 |
| SP Logistics Limited | Transport & logistics | 2020 |
| SP Sports UK CIC | Education | 2021 |
| Space & Vision Ltd | Arts & recreation | 2024 |
| Spacecom Ltd | Construction | 2010 |
| Spacemaker Inc Limited | Manufacturing | 2024 |
| Spacepetrol Limited | Extraterritorial | 2000 |
| Spacespeedy EFS Limited | Extraterritorial | 2005 |
| Spartans Events Limited | Arts & recreation | 2022 |
| Spartans Rufc Limited | Arts & recreation | 2022 |
| Specter Properties Limited | Real estate | 2025 |
| Specter Recruitment Limited | Administrative & support | 2018 |
| Spectrum AV Ltd | Professional & scientific | 2014 |
| Spectrum Holdings Limited | Professional & scientific | 1990 |
| Spek Noise Control Ltd | Manufacturing | 2006 |
| Spend and Raise Limited | Administrative & support | 2013 |
| Spgi Holdings Limited | Financial services | 2024 |
| Sphere Asset Management Ltd | Real estate | 2019 |
| Sphere Compliance Management Ltd | Professional & scientific | 2022 |
| Sphere Group Management Ltd | Professional & scientific | 2022 |
| Sphere Investment Group Limited | Financial services | 2020 |
| SPI Limited | Real estate | 2014 |
| Spicer and Yarwood Limited | Financial services | 2014 |
| Spillfabrikken Limited | Wholesale & retail | 2024 |
| Spires Electrical Limited | Construction | 2022 |
| Spires First AID Ltd | Education | 2024 |
| Spires Heating & Plumbing Ltd | Construction | 2025 |
| Spires Independent Properties Limited | Real estate | 2016 |
| Spires Roofing Limited | Construction | 2022 |
| Spiritual Group Ltd | Hospitality | 2018 |
| Spiritual Pathways Limited | Education | 2011 |