| Shikra Communications Limited | Wholesale & retail | 2018 |
| Shikra Global Ltd | Mining & quarrying | 2025 |
| Shimmin Plumbing Limited | Construction | 2003 |
| Shining Management Ltd | Administrative & support | 2002 |
| Shinyagna Ltd | Administrative & support | 2021 |
| Shiraz & Sons Investments Ltd | Construction | 2024 |
| Shivadari Ltd | Hospitality | 2024 |
| Shivalik Solutions Ltd | Information & communication | 2018 |
| SHK Printing Limited | Manufacturing | 2025 |
| Shoe Emporium Ltd | Wholesale & retail | 2017 |
| Shop Jollof Limited | Wholesale & retail | 2024 |
| Shop Viet UK Limited | Wholesale & retail | 2017 |
| SHOPLOCALLY50 Limited | Wholesale & retail | 2023 |
| Shopmusehair Ltd | Wholesale & retail | 2026 |
| Shopsmartly Ltd | Wholesale & retail | 2025 |
| Shoreditch Dog House Limited | Health & social care | 2016 |
| Shoreline Mechanical Ltd | Energy | 2022 |
| Short Circuit Electrical Contractors Ltd | Construction | 2024 |
| Short Circuit Renewables Ltd | Construction | 2024 |
| Shot Shilajit Limited | Health & social care | 2023 |
| Shotoku Limited | Professional & scientific | 2004 |
| Shreespm Limited | Wholesale & retail | 2025 |
| Shri Meenatchi Amman (Hindu) Temple Ltd | Other services | 2013 |
| SHS Lawyers Ltd | Professional & scientific | 2023 |
| Shutterman Ltd | Construction | 2021 |
| Shutterworks Ltd | Construction | 2023 |
| Shuttle Creative Ltd | Professional & scientific | 2021 |
| Shylov Group Limited | Real estate | 2022 |
| Sicav Investment Services Limited | Financial services | 1999 |
| Sidleyz Ltd | Hospitality | 2024 |
| Sidney Cubbage (Heating and Ventilating) Limited | Construction | 1983 |
| Siewert Developments Ltd | Construction | 2021 |
| Sieze the Means Limited | Professional & scientific | 2024 |
| SIGN2GO Ltd | Education | 2022 |
| SIGN89 Limited | Manufacturing | 2021 |
| Signature Assets Ltd | Real estate | 2025 |
| Signature Audio Limited | Information & communication | 2021 |
| Signature Blend Limited | Manufacturing | 2026 |
| Signature Creative Media Ltd | Information & communication | 2002 |
| Signature Leadership Training Limited | Professional & scientific | 2019 |
| Signature Line Travel Limited | Transport & logistics | 2022 |
| Signature Software Limited | Information & communication | 2015 |
| Signature Vehicle Hire Ltd | Administrative & support | 2020 |
| Signatures Security Ltd | Other services | 2025 |
| Signwide Pro Ltd | Administrative & support | 2025 |
| Silent Sounds Communications (Holdings) Limited | Financial services | 2023 |
| Silent Sounds Communications Ltd | Professional & scientific | 2012 |
| Silkflow Ltd | Water & waste | 2013 |
| Silkroad Transport Limited | Transport & logistics | 2018 |
| Silsila E Ameenia CIC | Education | 2026 |
| Silva Furniture Ltd | Manufacturing | 2021 |
| Silva Machinery Care Limited | Other services | 2014 |
| Silvano Ltd | Construction | 2024 |
| Silver Nimbus Technologies Limited | Information & communication | 2024 |
| Silver Street Management Company (Hull) Limited | Households | 2007 |
| Silver TON Bear Ltd | Extraterritorial | 2015 |
| Silvermere Developments Limited | Administrative & support | 2001 |
| Silveroak Property Services Ltd | Real estate | 2025 |
| Silverwood Construction Ltd | Construction | 2025 |
| Silverwood Place Management Company Limited | Households | 2021 |
| Simatt House Owners Association Limited | Households | 1993 |
| Simba Property Services Limited | Real estate | 2024 |
| Simmonds Studio Limited | Professional & scientific | 2009 |
| Simon Hart Marketing Ltd | Professional & scientific | 2018 |
| Simon Saves Ltd | Professional & scientific | 2020 |
| Simpart NO.256 Limited | Arts & recreation | 2003 |
| Simple Automated Workflows Ltd | Information & communication | 2019 |
| Simple Energy Renewals Limited | Other services | 2014 |
| Simple Innovation Associates Ltd | Information & communication | 2011 |
| Simplex Technologies Ltd | Information & communication | 2022 |
| Simply Healthy Grocers Ltd | Wholesale & retail | 2025 |
| Simply Purple Limited | Information & communication | 2025 |
| Simply Slow Ltd | Construction | 2026 |
| Simplyvilla Limited | Construction | 2023 |
| Simprojects Limited | Information & communication | 2016 |
| Simpson & Colvin Limited | Financial services | 2002 |
| Simpson Dean Limited | Administrative & support | 2013 |
| Sims Consultancy Services Ltd | Professional & scientific | 2019 |
| Sims Education Ltd | Education | 2019 |
| Singleton Oak Limited | Financial services | 2024 |
| Singpress Limited | Arts & recreation | 1995 |
| SIP Structure Limited | Administrative & support | 2017 |
| Sipto Ltd | Information & communication | 2017 |
| SIR Cliff Plastering Services Limited | Construction | 2023 |
| Sirat Solutions Limited | Information & communication | 2013 |
| Sircle Consultants Ltd | Construction | 2026 |
| Siri Technologies Ltd | Information & communication | 2022 |
| Siritech Consulting Limited | Information & communication | 2015 |
| Sistrum Pictures Ltd | Information & communication | 2016 |
| Site Building Services Limited | Construction | 2023 |
| Site Lift Website Ltd | Information & communication | 2020 |
| Site Management Consultants Limited | Households | 2007 |
| Sitwell Surveyors Ltd | Professional & scientific | 2024 |
| SIX Five Management Limited | Households | 2005 |
| Sixdegrees Family Ltd | Information & communication | 2026 |
| Sixfold International Ltd | Professional & scientific | 2005 |
| Sixfold Limited | Professional & scientific | 1990 |
| Sixth Sun Ltd | Information & communication | 2013 |
| SJ Accountants Ltd | Financial services | 2018 |
| SJ Medical Consultancy Ltd | Health & social care | 2021 |