| Sheldon School | Education | 2011 |
| Sheldon School Trading Limited | Arts & recreation | 2015 |
| Sheldon Social Ltd | Administrative & support | 2010 |
| Shera Collections Ltd | Wholesale & retail | 2025 |
| Sheridan Building Services Ltd | Construction | 2017 |
| Sherston Boarding Kennels Limited | Administrative & support | 2008 |
| Sheung MAY Holdings Limited | Real estate | 2017 |
| Shic Limited | Administrative & support | 2001 |
| Shina's Kitchen Ltd | Hospitality | 2024 |
| Shindy Ltd | Information & communication | 2024 |
| Shipsprint Ltd | Transport & logistics | 2023 |
| Shiraz Interiors Limited | Wholesale & retail | 2022 |
| SHIRE1 Ltd | Transport & logistics | 2022 |
| Shires Building Services Investments Ltd | Construction | 2015 |
| Shires Building Services Limited | Construction | 1994 |
| Shock Basketball Club Limited | Arts & recreation | 2023 |
| Shoreside International Ltd | Other services | 2012 |
| Shorncote & Co Limited | Real estate | 2025 |
| Shostakovich Ltd | Information & communication | 2015 |
| Showell Business Park Ltd | Wholesale & retail | 2011 |
| Shrinking Globe Limited | Information & communication | 2004 |
| Shrubbery Road Management Company Limited | Extraterritorial | 1989 |
| SHS Property Solutions Ltd | Real estate | 2023 |
| SI FI DEV Ltd | Information & communication | 2025 |
| SIB Marine Ltd | Arts & recreation | 2023 |
| Side Hustle Kitchen Ltd | Hospitality | 2025 |
| Siderpark Ltd | Professional & scientific | 2015 |
| Sideview Homesearch Limited | Administrative & support | 2017 |
| Sideview Inventories Limited | Real estate | 2017 |
| Sidnell Creative Limited | Information & communication | 2016 |
| Sidnell Financial Limited | Financial services | 2025 |
| Sidnell Property Limited | Real estate | 2025 |
| Siemko Limited | Transport & logistics | 2012 |
| Signature Insurance Services Limited | Financial services | 2006 |
| Signature Rail Limited | Information & communication | 1990 |
| Signature Shine Ltd | Administrative & support | 2026 |
| Signs Chippenham Ltd | Manufacturing | 2020 |
| Silvatica | | 1997 |
| Silver FOX GIN Ltd | Administrative & support | 2016 |
| Silver Street Garage Limited | Wholesale & retail | 2023 |
| Silver Willowe Care Ltd | Health & social care | 2026 |
| Silvey Enterprises Limited | Professional & scientific | 2019 |
| Simon Church Electrical Contractor Limited | Construction | 2002 |
| Simon Gingell Carpentry Services Ltd | Construction | 2014 |
| Simply Cells Limited | Administrative & support | 2011 |
| Simply Glazing Ltd | Construction | 2013 |
| Simply Rigging Services Limited | Administrative & support | 2005 |
| Simplyforkids Ltd | Professional & scientific | 2015 |
| Simswear Ltd | Wholesale & retail | 2021 |
| SIO Universal Ltd | Wholesale & retail | 2026 |
| Sister and Company Cosmetics Ltd | Wholesale & retail | 2023 |
| Sivara Limited | Other services | 2007 |
| SIX Bells Hospitality Ltd | Hospitality | 2024 |
| SIX Eight Development Limited | Construction | 2025 |
| SIX Four Hundred Limited | Households | 2021 |
| SJ Butler Engineering Limited | Manufacturing | 2013 |
| SJ Electrical Wiltshire Ltd | Construction | 2017 |
| SJC Electronic Consultants Ltd | Professional & scientific | 2025 |
| SJD Financial Services Limited | Financial services | 2010 |
| SJF Engineering (Civil & Structural) Ltd | Professional & scientific | 2025 |
| SJH Communications Ltd | Professional & scientific | 2024 |
| SJM Project Futures Ltd | Professional & scientific | 2025 |
| SJS Consulting (UK) Limited | Administrative & support | 2010 |
| SJS Information Systems Limited | Information & communication | 2003 |
| SJS Transport Limited | Wholesale & retail | 2020 |
| Skayn Ltd | Professional & scientific | 2024 |
| Skelton & Co Accounting Ltd | Professional & scientific | 2025 |
| Sketchlight Limited | Information & communication | 2014 |
| Skillsat Limited | Information & communication | 2022 |
| Skinner Property Services Ltd | Construction | 2021 |
| Skintuition Consulting Ltd | Professional & scientific | 2026 |
| Skippers Driving School Ltd | Education | 2023 |
| SKJ Aesthetics Ltd | Health & social care | 2020 |
| SKS Info Limited | Real estate | 2020 |
| Skua (UK) Limited | Construction | 2014 |
| Skuse Solutions Limited | Administrative & support | 2013 |
| Skylight Freight Ltd | Transport & logistics | 2020 |
| Skyline Heating Services Limited | Construction | 2003 |
| Skyline Investments Limited | Financial services | 2022 |
| Skyline Rental Properties Limited | Real estate | 2022 |
| Slade Roofing Limited | Construction | 2002 |
| Slaughterford Mill Limited | Real estate | 2009 |
| SLD Wiltshire Limited | Other services | 2025 |
| Slick Travel Limited | Administrative & support | 2025 |
| Slim-Be Limited | Wholesale & retail | 2014 |
| Slip&Grip Automotive Ltd | Wholesale & retail | 2018 |
| SLV Consulting Ltd | Information & communication | 2001 |
| SMA Chippenham Limited | Real estate | 2026 |
| Small Business Collaborative Ltd | Professional & scientific | 2018 |
| Smart AGE Education Ltd | Education | 2025 |
| Smart City Media Limited | Administrative & support | 2011 |
| Smart Engineering Services Limited | Professional & scientific | 1995 |
| Smart Homes & Rentals Ltd | Households | 2025 |
| Smart Monkey Golf Ltd | Manufacturing | 2026 |
| Smart Owls Limited | Education | 2012 |
| Smart Tech Chippenham Ltd | Other services | 2017 |
| Smartcell Networks Limited | Extraterritorial | 2019 |
| Smartcellone Ltd | Wholesale & retail | 2022 |
| Smartech Energy Ltd | Professional & scientific | 2014 |
| Smartech Holdings Limited | Financial services | 2022 |