| Shoxxs KIT and Clothing Ltd | Wholesale & retail | 2014 |
| SHR Developments Ltd | Construction | 2021 |
| Shrager Creative Ltd | Professional & scientific | 2012 |
| Shredded Neat Limited | Administrative & support | 2011 |
| Shredded Neat UK LLP | | 2016 |
| Shree Laxmi Narayan Solutions Limited | Information & communication | 2017 |
| Shree Medical Services Ltd. | Health & social care | 2016 |
| Shrestha Transport Ltd | Transport & logistics | 2020 |
| Shreyash Global LLP | | 2025 |
| Shreyash Prime Ltd | Health & social care | 2026 |
| Shroomy & Pando Ltd. | Real estate | 2025 |
| Shufflepress Limited | Information & communication | 2024 |
| Shum & Co Consulting Ltd | Information & communication | 2020 |
| Shun Fafa Limited | Hospitality | 2024 |
| Shutter Leaf Limited | Information & communication | 2014 |
| Shuttle Thread Limited | Information & communication | 2010 |
| SI Fixers Ltd | Construction | 2021 |
| SI Jones Creative Ltd | Professional & scientific | 2025 |
| Sian Thomas Enterprises Limited | Professional & scientific | 2010 |
| Sidan Limited | Professional & scientific | 2010 |
| Siddhi Solutions Ltd | Information & communication | 2019 |
| Sidegrange Limited | Real estate | 1972 |
| SIF Association UK | Information & communication | 2011 |
| Sightscreen HR Ltd | Administrative & support | 2022 |
| Sigma Performance SC Limited | Wholesale & retail | 2025 |
| Signal UK Limited | Manufacturing | 2005 |
| Signalmesh Ltd | Information & communication | 2025 |
| Signature Surveyors Ltd | Professional & scientific | 2019 |
| Silhouette Glass Limited | Construction | 2017 |
| Silk Swallow Limited | Professional & scientific | 2012 |
| Silly Hugo Ltd | Wholesale & retail | 2026 |
| Silly Mission Productions Ltd | Arts & recreation | 2025 |
| Silver Line Wealth Ltd | Professional & scientific | 2021 |
| Silver Lord INT Ltd | Professional & scientific | 2025 |
| Silver Lord Limited | Professional & scientific | 2021 |
| Silver Sigma Limited | Arts & recreation | 2013 |
| Silverbirch Advisory Limited | Professional & scientific | 2026 |
| Silverdale EG Limited | Wholesale & retail | 2019 |
| Silverdale Homes Ltd | Real estate | 2024 |
| Silverdale Mews Holdings Limited | Households | 2024 |
| Silverdale TW Limited | Wholesale & retail | 2011 |
| Silverline Games Limited | Information & communication | 2026 |
| Silvero Investments Limited | Construction | 2000 |
| Silvery Limited | Wholesale & retail | 2009 |
| Simkin Solutions Limited | Information & communication | 2000 |
| Simmons Property Limited | Real estate | 2015 |
| Simon Gaeremynck Limited | Information & communication | 2025 |
| Simon Judd Booksellers Limited | Transport & logistics | 1982 |
| Simon Kidd Golf Ltd | Education | 2024 |
| Simon Male Limited | Real estate | 2016 |
| Simon Mannion Limited | Professional & scientific | 2020 |
| Simon Thomas (UK) Limited | Financial services | 2010 |
| Simon Thomas LLP | | 2010 |
| Simon Turner Consulting Limited | Information & communication | 2020 |
| Simon’S Cars Limited | Transport & logistics | 2020 |
| Simplify Your Group Limited | Professional & scientific | 2022 |
| Simply OPS LLP | | 2025 |
| Simply ST. Lucia Limited | Administrative & support | 2008 |
| Simsen (Property Developments) Limited | Real estate | 1977 |
| Simth Property Ltd | Real estate | 2023 |
| Sineflow Ltd. | Information & communication | 2015 |
| Single Source Binding Machines Limited | Wholesale & retail | 2011 |
| Singleton Dental Limited | Health & social care | 2015 |
| Sino Galleon Limited | Financial services | 2021 |
| SIP Water Limited | Water & waste | 2023 |
| Sipgo Ltd | Administrative & support | 2024 |
| SIR David Amess Cpuk | Education | 2026 |
| Sisyphus Solutions Limited | Professional & scientific | 2025 |
| Sitacs Ltd | Wholesale & retail | 2003 |
| Sited Limited | Administrative & support | 2016 |
| Sitsmart Limited | Professional & scientific | 1993 |
| Sivang UK Trading Ltd | Hospitality | 2013 |
| Sixtyfive Property Management Ltd | Real estate | 2025 |
| SJ Consultants Limited | Administrative & support | 2007 |
| SJ Reilly Ltd | Professional & scientific | 2025 |
| SJ Tuition Ltd | Education | 2011 |
| SJ Zenodon Ltd | Health & social care | 2023 |
| SJB (Holdings) Ltd | Professional & scientific | 2013 |
| SJB Property Rentals Ltd | Real estate | 2022 |
| SJC Carpentry Limited | Manufacturing | 2015 |
| SJC UK Ltd | Professional & scientific | 2008 |
| SJD Group Limited | Administrative & support | 2024 |
| SJD Projects Limited | Real estate | 2007 |
| SJF Nelson (Writer) Limited | Professional & scientific | 2019 |
| SJH Digital Ltd | Professional & scientific | 2014 |
| SJL Associates Limited | Professional & scientific | 2000 |
| SJM Consultancy Solutions Limited | Professional & scientific | 2015 |
| Sjsoftware Limited | Information & communication | 2026 |
| Sjwhomeimprovements Ltd | Construction | 2022 |
| Sk:Nez Ltd | Health & social care | 2025 |
| Skafos Technologies Limited | Professional & scientific | 2025 |
| Skalego Limited | Professional & scientific | 2017 |
| SKH Consulting Ltd | Professional & scientific | 2024 |
| Skill Order Limited | Education | 2023 |
| Skills for Employment Building Contractors Limited | Construction | 2011 |
| Skills for Employment Limited | Education | 2011 |
| Skills for Employment Mobile Services Limited | Administrative & support | 2018 |
| Skin Inclusive Limited | Wholesale & retail | 2025 |
| Skin Therapy the Pantiles Limited | Other services | 2023 |
| Skinaddict Ltd | Wholesale & retail | 2014 |