| Staplecote Limited | Professional & scientific | 2013 |
| Staplegrove Consultants Ltd | Professional & scientific | 2011 |
| Staplegrove Contractors Limited | Construction | 1999 |
| Staplehay Auto Services Ltd | Wholesale & retail | 2016 |
| Starbubs Ltd | Other services | 2021 |
| Starfield Biproducts Limited | Professional & scientific | 2024 |
| Starfield Transport Limited | Information & communication | 2024 |
| Staring LLP | | 2012 |
| Stark Consulting Ltd | Professional & scientific | 2025 |
| Starry Dog Books Limited | Information & communication | 2002 |
| Station Road Taunton Ltd | Hospitality | 2026 |
| Station View Property Management Company Limited | Households | 2020 |
| Staxton Properties Limited | Real estate | 2017 |
| Staycation Investor Ltd | Financial services | 2021 |
| STC Freeman Limited | Financial services | 2022 |
| Stealth Properties Limited | Real estate | 2014 |
| Stealthlink Ltd | Wholesale & retail | 1998 |
| Steelers Homes Limited | Real estate | 2021 |
| Steelers Plumbing & Heating Limited | Extraterritorial | 2022 |
| Steerside Limited | Manufacturing | 1962 |
| Steinhage Holdings Ltd | Financial services | 2023 |
| Steliana Health Ltd | Health & social care | 2018 |
| Stella Creations Ltd | Wholesale & retail | 2017 |
| Stella Creations Upholstery Limited | Other services | 2025 |
| Stellar M Ltd | Health & social care | 2016 |
| Stenners (Porlock) Limited | Real estate | 1951 |
| Step UP Rehab Ltd | Health & social care | 2020 |
| Stephen & Co Limited | Real estate | 2002 |
| Stephenson Renovations Limited | Real estate | 2023 |
| Stepping Stones (SW) Limited | Education | 2009 |
| Stepping-Stones Care SW Limited | Health & social care | 2021 |
| Sterling Accountancy Services Ltd | Professional & scientific | 2003 |
| Sterling Independent Ltd | Financial services | 2019 |
| Stetler LLP | | 2012 |
| Steve Bishop Pest Control Services Ltd | Administrative & support | 2016 |
| Steve Bushell Limited | Administrative & support | 1976 |
| Steve Davey Building Limited | Construction | 2002 |
| Steve Hignett Video Productions Ltd | Information & communication | 2016 |
| Steve Raybould Limited | Construction | 2003 |
| Steven Hayter Limited | Construction | 2018 |
| Steven Pearce Associates Limited | Wholesale & retail | 2008 |
| Steven Sidhu Wealth Management Ltd | Financial services | 2013 |
| Stevens Holdings Limited | Professional & scientific | 2019 |
| Stew Law Ltd | Financial services | 2025 |
| Stilings Limited Liability Partnership | | 2001 |
| Stinky Dog Ltd | Wholesale & retail | 2019 |
| Stirland Developments Ltd | Real estate | 2024 |
| Stirling Enterprise Limited | Financial services | 2024 |
| Stoake Ltd | Construction | 2014 |
| Stockton Developments Limited | Construction | 2024 |
| Stockton Hire Ltd | Administrative & support | 2021 |
| Stoke Road Taunton Allotments CIC | Agriculture & fishing | 2020 |
| Stokely Healthcare Ltd | Health & social care | 2021 |
| Stokes Fine Wines Limited | Wholesale & retail | 1987 |
| Stokrotka Taunton Ltd | Wholesale & retail | 2019 |
| Stone and Partners (Taunton) Limited | Professional & scientific | 2018 |
| Stone Oak Developments Limited | Construction | 2004 |
| Stonegallows Clinic Ltd | Health & social care | 2023 |
| Stoneminster Property Limited | Real estate | 2020 |
| Stonewall Home Care Limited | Health & social care | 2022 |
| Stoneyford Management Company Limited | Households | 2025 |
| Stoploss Insurance Services Limited | Financial services | 1999 |
| Stor 103 Ltd | Energy | 2016 |
| Stor 106 Ltd | Energy | 2016 |
| Stor 107 Ltd | Energy | 2016 |
| Stor 108 Ltd | Energy | 2016 |
| Stor 119 Ltd | Energy | 2016 |
| Stor 120 Ltd | Energy | 2016 |
| Stor 121 Ltd | Energy | 2016 |
| Stor 122 Ltd | Energy | 2016 |
| Stor 123 Ltd | Energy | 2016 |
| Stor 130 Ltd | Energy | 2016 |
| Stor 132 Ltd | Energy | 2016 |
| Stor 136 Ltd | Energy | 2016 |
| Stor 140 Ltd | Energy | 2016 |
| Stor 146 Ltd | Energy | 2016 |
| Stor 148 Ltd | Energy | 2016 |
| Stor 149 Ltd | Energy | 2016 |
| Stor Power Developments Ltd | Extraterritorial | 2016 |
| Stor Power Ltd | Financial services | 2015 |
| Story (SW) Limited | Real estate | 2024 |
| Story Records Limited | Arts & recreation | 2013 |
| Story Seeds Somerset CIC | Education | 2024 |
| Stowell Tunnelling Limited | Construction | 2018 |
| Stradel Integrated Services Limited | Administrative & support | 2025 |
| Stradel Property Ltd | Real estate | 2026 |
| Strange AI Ltd | Information & communication | 2025 |
| Strata Insight Limited | Professional & scientific | 2026 |
| Strategia.International Ltd | Professional & scientific | 2024 |
| Strategic Effect Limited | Professional & scientific | 2014 |
| Strathaird FIC Ltd | Financial services | 2026 |
| Strathenry Limited | Real estate | 2004 |
| Stratosphere Holdings Ltd | Professional & scientific | 2018 |
| Stratospherix Ltd | Information & communication | 2009 |
| Stratton on the Fosse Farming Company Ltd | Agriculture & fishing | 2013 |
| Straw Management Ltd | Real estate | 2005 |
| Streamcross (Somerset) Limited | Construction | 2003 |
| Street Food Fiesta Ltd | Hospitality | 2018 |
| Street Shakes Limited | Wholesale & retail | 2019 |
| Street Toyz Ltd | Wholesale & retail | 2003 |