| SKB Holdings Limited | Financial services | 2018 |
| Skie Properties Ltd | Real estate | 2021 |
| Skin Addiction Ltd | Other services | 2022 |
| Skinner TTC Ltd | Professional & scientific | 2013 |
| Skinsetics Ltd | Health & social care | 2025 |
| Skip Hire Basildon Limited | Water & waste | 2012 |
| SKM Boxing Limited | Arts & recreation | 2024 |
| SKR Technology Ltd | Professional & scientific | 2019 |
| Skskin Ltd | Extraterritorial | 2021 |
| Sky&Co Ltd | Wholesale & retail | 2025 |
| Sky's the Limit Contract Lifting Services Ltd | Construction | 2015 |
| Skyline Roofing Solutions Ltd | Construction | 2020 |
| SL LED UK Limited | Administrative & support | 2025 |
| Slate & Shingle Limited | Construction | 2025 |
| Sleepy Blue Designs Ltd | Construction | 2022 |
| Sleepy Teepee Ltd | Information & communication | 2026 |
| Slide in Ltd | Hospitality | 2022 |
| Slm-Projects Ltd | Construction | 2024 |
| Sloane Avenue Estates Ltd | Real estate | 2025 |
| SM Creative and Professional Services Ltd | Information & communication | 2018 |
| SM Real Estate Investments Ltd | Hospitality | 2023 |
| SM Sashes Ltd | Construction | 2007 |
| Smaac Consulting Limited | Professional & scientific | 2026 |
| Smart Border Clearance Ltd | Transport & logistics | 2017 |
| Smart Move 09 Limited | Real estate | 2012 |
| Smartcraft Landscapes and Driveways Limited | Administrative & support | 2021 |
| Smarter Mortgage Solutions Limited | Financial services | 2008 |
| Smarthouse Corp Limited | Professional & scientific | 2018 |
| Smith & Smith Consulting Ltd | Professional & scientific | 2014 |
| Smiths SET Solid Ltd | Wholesale & retail | 2020 |
| SMK Fire and Security Limited | Administrative & support | 2016 |
| Smokin Griddle Ltd | Hospitality | 2019 |
| Smokin Griddle the Burger Delivery Company Limited | Hospitality | 2015 |
| Smooth Lines Sealants Ltd | Construction | 2026 |
| Smqa Limited | Information & communication | 2014 |
| SN Props Limited | Real estate | 2020 |
| Snack Shack Catering Co Ltd | Hospitality | 2026 |
| Soane Properties Ltd | Real estate | 2009 |
| Sobera Limited | Other services | 2009 |
| Soetan Solutions Ltd | Transport & logistics | 2026 |
| Sofito Consultancy Limited | Professional & scientific | 2009 |
| Sofito Holdings Limited | Financial services | 2023 |
| Solar Bioenergy Ltd | Energy | 2025 |
| Solar Ventus Energy Limited | Energy | 2018 |
| Solar Ventus Limited | Administrative & support | 2010 |
| Solid Colour Design Ltd | Arts & recreation | 2022 |
| Solid Media Solutions Limited | Construction | 2025 |
| Solid-Core Composite Doors Ltd | Administrative & support | 2019 |
| Solos Create Ltd | Wholesale & retail | 2022 |
| Solstar Insurance Brokers Limited | Financial services | 2022 |
| Something Live Productions Ltd | Professional & scientific | 2023 |
| Somnus Salus Ltd | Health & social care | 2024 |
| Sopgio Limited | Hospitality | 2025 |
| Sophie Andrews Limited | Professional & scientific | 2019 |
| Sors Botanicals Ltd | Wholesale & retail | 2024 |
| Sott Care Limited | Public administration | 2023 |
| Soundsmith London Ltd | Professional & scientific | 2011 |
| South Chelsea Property Company Limited | Real estate | 2014 |
| South East Energy Ltd | Construction | 2026 |
| South Grill Catering Ltd | Hospitality | 2019 |
| South Steel Ltd | Wholesale & retail | 2025 |
| Southbank Vineyard Ltd | Agriculture & fishing | 2023 |
| Southcare Limited | Households | 1979 |
| Southeast Construction & Recruitment Ltd | Construction | 2014 |
| Southfields Engineering Limited | Manufacturing | 1979 |
| Southminster Consultancy Associates Limited | Administrative & support | 2008 |
| SOW and Flourish Limited | Wholesale & retail | 2026 |
| Sowena Taverns Ltd | Real estate | 2007 |
| Space AID Lofts Ltd | Construction | 2019 |
| Space Trips (Essex) Limited | Professional & scientific | 2017 |
| Spacey Limited | Professional & scientific | 2013 |
| Spark Design & Production Limited | Arts & recreation | 2005 |
| Sparklers of Billericay Ltd | Administrative & support | 2012 |
| Sparks Welding Co. Ltd | Manufacturing | 1997 |
| Spartan Markets Limited | Financial services | 2025 |
| Spartan Property Holdings Limited | Financial services | 2024 |
| Spear Contracts Ltd | Construction | 2026 |
| Speci-Fire Ltd | Professional & scientific | 2017 |
| Specialist Commercial Joinery Limited | Construction | 2013 |
| Specialist Pathways Limited | Professional & scientific | 2026 |
| Spectrum Clinical Services Ltd | Health & social care | 2022 |
| Speedbird Four Limited | Real estate | 2018 |
| Spencer Build Limited | Construction | 2007 |
| Spencer Chapman Ltd | Construction | 2020 |
| Spera Solutions Limited | Information & communication | 2021 |
| Sphinx Electrical Ltd | Construction | 2000 |
| Spice 1 UK Ltd | Hospitality | 2007 |
| Spiced RUM & Smoke Ltd | Hospitality | 2025 |
| Spillbutters Investments Ltd | Financial services | 2025 |
| SPM Accounting Limited | Professional & scientific | 2006 |
| SPM Lift Consultant Limited | Professional & scientific | 2016 |
| Sports Marketing & Promotions Limited | Professional & scientific | 2002 |
| Spot on Plumbing & Heating Services Limited | Construction | 2010 |
| Spot Studios Limited | Professional & scientific | 2003 |
| Sprayaway Group Limited | Wholesale & retail | 2023 |
| Spring Software Solutions Limited | Information & communication | 2010 |
| Sprojectsuk Ltd | Construction | 2023 |
| Spudley Limited | Professional & scientific | 2011 |
| Spurgate Management Limited | Households | 1999 |
| Squiggles Day Nursey (Wormley) Limited | Education | 2016 |