| Shinecrown Limited | Real estate | 2004 |
| Shingleton & Co. Limited | Administrative & support | 1997 |
| Shipstar Partnership | | 1999 |
| SHL Apac Finance Limited | Financial services | 2022 |
| SHL Group Limited | Professional & scientific | 1977 |
| SHL People Solutions Group Holdings Ltd. | Financial services | 1997 |
| Shoes@Last Limited | Wholesale & retail | 2002 |
| Shokk Clothing Ltd | Wholesale & retail | 2007 |
| Shoot Photographic Limited | Extraterritorial | 1996 |
| Shoqata Bemirese Jetimat E Ballkanit | Health & social care | 2020 |
| Shor Properties Limited | Real estate | 2005 |
| Shorea Capital UK Ltd | Real estate | 2024 |
| Showreal Productions Limited | Information & communication | 2002 |
| Shree Siddhivinayaka Asset Ltd | Real estate | 2007 |
| Shreenathji Limited | Real estate | 2015 |
| Shrewdhold Limited | Households | 1987 |
| Shrewsbury House School Trust Limited | Education | 1979 |
| Shriji Property Limited | Real estate | 2004 |
| Shrubland Investments Limited | Real estate | 1958 |
| Shuva Ltd | Hospitality | 2023 |
| Shyam Barrat Limited | Professional & scientific | 2007 |
| Sian Allan Consultancy Limited | Professional & scientific | 2007 |
| Siber Limited | Information & communication | 1997 |
| Sident Dental Systems Ltd. | Health & social care | 1990 |
| Sident Limited | Health & social care | 1982 |
| Sienna Gray Productions Ltd | Extraterritorial | 2023 |
| Siftlord Securities Limited | Wholesale & retail | 1984 |
| Sigaram EYT Ltd | Education | 2023 |
| Signal Driving School Ltd | Education | 2006 |
| Signaltec Limited | Wholesale & retail | 2024 |
| Signor Spumante Limited | Real estate | 1985 |
| Silent Witness Enterprises Ltd. | | 2001 |
| Silentpoint Limited | Administrative & support | 2000 |
| Silentpoint Property Limited | Real estate | 2006 |
| Silhouette Promotions Limited | | 1983 |
| Silhouette Trading Company Limited | Transport & logistics | 1984 |
| Silk & Confetti Events Ltd | Administrative & support | 2022 |
| Silk Road Services Ltd | Administrative & support | 1995 |
| Silkstar Limited | | 1988 |
| Sillence and Clow Limited | | 1984 |
| Silver Birch 3 Limited | Real estate | 2026 |
| Silvercress Limited | Wholesale & retail | 2004 |
| Silvertrain Ltd | Professional & scientific | 2007 |
| Simioni and Sons Limited | Manufacturing | 2016 |
| Simmons Taylor Hall Ltd | Professional & scientific | 2003 |
| Simon Williamson Properties Ltd | Real estate | 2007 |
| Simple Wellbeing Ltd | Other services | 2021 |
| Simply Crown & Bridge Limited | Health & social care | 2002 |
| Simply Hormones Limited | Professional & scientific | 2007 |
| Simply Mouldings (Contracts) Limited | Construction | 1978 |
| Simply Mouldings Limited | Manufacturing | 1981 |
| Simply Sports Limited | Wholesale & retail | 1983 |
| Simpson & NYE Limited | Wholesale & retail | 1985 |
| Simpson Financial Planning Limited | Financial services | 1998 |
| Sines Groundwork Ltd | Professional & scientific | 2006 |
| Sinolec Components Limited | Wholesale & retail | 2004 |
| Sinoscope Limited | Information & communication | 1993 |
| SIR Tax Accountants Limited | Professional & scientific | 2007 |
| SIXTYSIX8 Ltd | Wholesale & retail | 2016 |
| SJ Property Partners Ltd | Real estate | 2021 |
| SJC (Highgate) Limited | Extraterritorial | 1999 |
| SJW Interiors Ltd | Administrative & support | 2017 |
| SK SAI Ltd | Real estate | 2017 |
| Skilled Hands Ltd | Construction | 2016 |
| Skills Partnership (South London) Limited | Professional & scientific | 1994 |
| Skipping Workshops U.K. Limited | Wholesale & retail | 2004 |
| SKL Investment Limited | Construction | 2015 |
| SKM Retail Ltd | Wholesale & retail | 2004 |
| SKS (Tn-Rh) Ltd | Professional & scientific | 2014 |
| Sksi Limited | Financial services | 2014 |
| SKV Wordwork Limited | Information & communication | 2004 |
| Skydon Limited | Construction | 2007 |
| Skyswift (UK) Limited | Transport & logistics | 2000 |
| Skywell Auto Ltd | Wholesale & retail | 2021 |
| Skywell Technologies Limited | Information & communication | 2003 |
| Slam One Limited | Real estate | 2020 |
| Sliding Wardrobe Warehouse Limited | Manufacturing | 2006 |
| SM4NET Limited | Extraterritorial | 2001 |
| Small Business Investment Company Limited | Financial services | 2007 |
| Small Business Support & Accounts Ltd | Professional & scientific | 2009 |
| Small Publishing Ltd | Arts & recreation | 2006 |
| Smart Gardening Ltd | Other services | 2012 |
| Smart Move Residential Limited | Real estate | 2020 |
| Smarter Services Group Limited | Financial services | 2023 |
| Smartest Trans Company Ltd | Transport & logistics | 2019 |
| Smartzi B2B Ltd | Transport & logistics | 2020 |
| Smartzi Limited | Information & communication | 2014 |
| Smigo Traders Limited | Wholesale & retail | 2021 |
| Smit Mobile Equipment (UK) Limited | Construction | 2001 |
| Smrd Accountancy Services Limited | Professional & scientific | 1990 |
| SMS Investments Limited | Real estate | 1998 |
| SNA London Trading Ltd | Transport & logistics | 2022 |
| Snowdenham Properties Limited | Construction | 1971 |
| Snowreed Limited | Professional & scientific | 1989 |
| SNR Property Investment Ltd | Real estate | 2026 |
| SNS Consultancy Limited | Professional & scientific | 2004 |
| SO Talented London Limited | Arts & recreation | 2018 |
| Sobek Services Limited | Administrative & support | 2000 |
| Social Sign Limited | Information & communication | 2025 |
| Softix Limited | Information & communication | 2005 |