| Shore Bound Ltd | Information & communication | 2026 |
| Shore Step Consultancy Ltd | Information & communication | 2026 |
| Short Builders Group Limited | Construction | 2019 |
| Short Lawns Garden Maintenance Ltd | Other services | 2019 |
| Short Sharp Ltd | Arts & recreation | 2023 |
| Shortwood Business Park Management Company Limited | Extraterritorial | 2007 |
| Shosc Sports & Social Ltd | Other services | 2025 |
| Shpl Holdings Ltd | Other services | 2026 |
| SHQ Ashton Ltd | Health & social care | 2021 |
| Shree Kara Services Ltd | Administrative & support | 2026 |
| Shree Mithran Trade Ltd | Administrative & support | 2024 |
| Shreeve Hallam Jones Ltd | Professional & scientific | 2016 |
| Shrewsbury Carpets Limited | Wholesale & retail | 2008 |
| Shropshire Innkeepers Ltd | Hospitality | 2025 |
| Shropshire Roofing Supplies Limited | Extraterritorial | 1986 |
| SHU Education Services Limited | Education | 2022 |
| SHU Trust | Education | 2011 |
| Shuaib E Store Limited | Wholesale & retail | 2025 |
| Shuaib Ltd | Health & social care | 2023 |
| Shuaib Pharma Ltd | Wholesale & retail | 2022 |
| Shubam RK Aura Limited | Wholesale & retail | 2026 |
| Shubh Leicester Ltd | Wholesale & retail | 2018 |
| Shubruchi Luxe Ltd | Wholesale & retail | 2025 |
| Shuju Catering International Limited | Transport & logistics | 2018 |
| Shukriya Limited | Hospitality | 2020 |
| Shum Limited | Health & social care | 2021 |
| Shumba Engineering Limited | Manufacturing | 2024 |
| Shumba Health Ltd | Health & social care | 2017 |
| Shumba Real Estate Limited | Real estate | 2022 |
| Shunem Healthcare Ltd | Health & social care | 2015 |
| Shush Instruments Ltd | Manufacturing | 2023 |
| Shutt Site Services Limited | Construction | 2015 |
| Shutter Comps Ltd | Wholesale & retail | 2026 |
| Shutter Exchange Limited | Wholesale & retail | 2026 |
| Shutterbug Panacea Limited | Professional & scientific | 2014 |
| Shutters by IAN Ltd | Wholesale & retail | 2020 |
| Shēk Interiors Ltd | Wholesale & retail | 2026 |
| SI Applied Limited | Administrative & support | 2002 |
| SI Jiahui Snooker Limited | Arts & recreation | 2024 |
| SI Optical (Yorkshire) Ltd | Real estate | 2017 |
| SI Whitstable Ltd | Hospitality | 2022 |
| Sian Developments Limited | Professional & scientific | 2024 |
| Siara Indian Ltd | Hospitality | 2025 |
| Sibanisi Limited | Public administration | 2018 |
| SIC Records Ltd | Arts & recreation | 2016 |
| Sickfade SA Limited | Other services | 2025 |
| Siddall Property Group Ltd | Financial services | 2025 |
| Siddhi Property Group Ltd | Real estate | 2026 |
| Side by Side Educational Psychology Ltd | Education | 2022 |
| Sidekick Public Relations Limited | Professional & scientific | 2016 |
| Sidell Gibson Architects Limited | Professional & scientific | 2013 |
| Sidell Gibson Design Limited | Professional & scientific | 2013 |
| Sidell Gibson Interiors Limited | Professional & scientific | 2007 |
| Sideone Ltd | Hospitality | 2025 |
| Sidewalk Specials CIC | Other services | 2016 |
| Sidings Park Limited | Real estate | 2022 |
| Sidney & Matilda Ltd | Hospitality | 2023 |
| Siege Properties UK Limited | Real estate | 2012 |
| Siel Energy Systems Limited | Manufacturing | 1991 |
| Sienna&Esme Time Limited | Wholesale & retail | 2020 |
| Sierra 1 Security Stewarding Ltd | Administrative & support | 2020 |
| Sierra 6 Ltd | Professional & scientific | 2024 |
| Sierra Bookworld Limited | Wholesale & retail | 2018 |
| SIERRA24SEVEN Ltd | Administrative & support | 2026 |
| Sieyal Ltd | Wholesale & retail | 2026 |
| SIG (IFC) Limited | Financial services | 2018 |
| SIG Building Solutions Limited | Extraterritorial | 1945 |
| SIG Building Systems Limited | Extraterritorial | 2012 |
| SIG Dormant Company Number Eight Limited | Extraterritorial | 1973 |
| SIG Dormant Company Number Eleven Limited | Extraterritorial | 2000 |
| SIG Dormant Company Number Seven Limited | Extraterritorial | 1990 |
| SIG Dormant Company Number SIX Limited | Extraterritorial | 1983 |
| SIG Dormant Company Number TEN Limited | Professional & scientific | 2003 |
| SIG Dormant Company Number Three Limited | Extraterritorial | 1987 |
| SIG EST Trustees Limited | Extraterritorial | 2005 |
| SIG European Holdings Limited | Professional & scientific | 2004 |
| SIG European Investments Limited | Professional & scientific | 1984 |
| SIG Group Life Assurance Scheme Trustees Limited | Extraterritorial | 1989 |
| SIG International Trading Limited | Extraterritorial | 1992 |
| SIG Logistics Limited | Extraterritorial | 1972 |
| SIG Manufacturing Limited | Extraterritorial | 1975 |
| SIG PLC | Professional & scientific | 1970 |
| SIG Retirement Benefits Plan Trustee Limited | Extraterritorial | 2006 |
| SIG Roofing Limited | Extraterritorial | 1989 |
| SIG Roofing Supplies Limited | Extraterritorial | 1996 |
| SIG Specialist Construction Products Limited | Extraterritorial | 1970 |
| SIG Trading Limited | Construction | 1979 |
| Sigma Physiotherapy Ltd | Other services | 2020 |
| Sigma Rose Properties Limited | Real estate | 2025 |
| Sigma Supply Chain Solutions Ltd | Other services | 2016 |
| Sigmadean Ltd | Hospitality | 2021 |
| Sigmas Traders Ltd | Wholesale & retail | 2026 |
| Sign Language Innovations Limited | Water & waste | 2008 |
| Sign Sealed Delivered Ltd | Administrative & support | 2016 |
| Signal Learning Limited | Education | 2021 |
| Signature by Grayson Limited | Other services | 2019 |
| Signature Cartel Ltd | Wholesale & retail | 2022 |
| Signature Falafel and Grill Limited | Hospitality | 2025 |
| Signature Jewels Limited | Wholesale & retail | 2026 |
| Signature Luxury Ltd | Wholesale & retail | 2026 |