| SAS Land Services Ltd | Agriculture & fishing | 2025 |
| Sasumaze Ltd | Real estate | 2021 |
| Satori Risk Limited | Administrative & support | 2020 |
| Saturn Consulting Limited | Professional & scientific | 2022 |
| Savile Court Ltd | Households | 2009 |
| Sayum Limited | Construction | 2012 |
| SB Commissioning Management Ltd | Professional & scientific | 2022 |
| SB Techno Solutions Limited | Wholesale & retail | 2009 |
| Sbbp Property Ltd | Construction | 2026 |
| SBC Cleaning Ltd | Administrative & support | 2024 |
| SBM Autos Limited | Wholesale & retail | 2021 |
| Scaleitwithsocials Ltd | Professional & scientific | 2025 |
| Scanfiber Composites UK Limited | Administrative & support | 2010 |
| Schofields Group PLC | Construction | 1985 |
| Scholl's Wellness Company Limited | Manufacturing | 2021 |
| Sci-Tech Laboratories Limited | Agriculture & fishing | 2005 |
| Sciantec Analytical Services Ltd. | Professional & scientific | 1991 |
| Scientific and Regulatory Services Limited | Professional & scientific | 2015 |
| Scon Copywriting Ltd | Professional & scientific | 2022 |
| Scootermart OK Care Centre Berkshire Limited | Wholesale & retail | 2001 |
| Scopi Consulting Ltd | Professional & scientific | 2014 |
| Scott Allum Mortgages Limited | Financial services | 2004 |
| Scott Aviation (Berkshire) Ltd | Manufacturing | 2022 |
| Scott Health & Safety Limited | Manufacturing | 1946 |
| Scott Homes Berkshire Ltd | Construction | 2016 |
| Screed Works Ltd | Manufacturing | 2018 |
| Scribe Solutions Limited | Professional & scientific | 2025 |
| Scrimbest Limited | | 1976 |
| Scrummy Yummy Cakes Ltd | Manufacturing | 2006 |
| Scumlife Ltd | Manufacturing | 2023 |
| SDG Contracting Limited | Administrative & support | 2026 |
| Sdsw Marketing Ltd | Administrative & support | 2012 |
| SDW Image Limited | Professional & scientific | 2007 |
| Seacole Health Ltd | Professional & scientific | 2016 |
| Sealease Limited | Administrative & support | 2025 |
| Seamless AV Integration Ltd | Construction | 2024 |
| Seamo Ltd | Health & social care | 2018 |
| Sean Carter Ltd | Construction | 2025 |
| Sears Property Limited | Real estate | 2010 |
| SEB Residential Ltd | Real estate | 2021 |
| Second Opinion Radiology Limited | Health & social care | 2025 |
| Secondhand Saint Limited | Wholesale & retail | 2024 |
| Secondopinion.Io Limited | Information & communication | 2025 |
| Secret SOC. Studio Ltd | Manufacturing | 2025 |
| Security UK (South) Ltd | Administrative & support | 2025 |
| Sedimentaryfill Ltd | Professional & scientific | 2017 |
| Seeb Electric Ltd | Manufacturing | 2025 |
| Sefton Court Limited | Households | 1991 |
| Seldan Property Management Ltd | Real estate | 2026 |
| Seldan Wealth Management Ltd | Professional & scientific | 2020 |
| Select Promotions (UK) Limited | Administrative & support | 2007 |
| Selenium Property Ltd | Real estate | 2022 |
| Sensitive Hearing Limited | Health & social care | 2011 |
| Sequent Innovation Ltd | Professional & scientific | 2016 |
| Serenityhousewales Limited | Administrative & support | 2021 |
| Service 20000 Limited | Information & communication | 2003 |
| Service Management Association Limited | Other services | 1991 |
| Set-Up Technologies Ltd | Wholesale & retail | 2020 |
| Seven Global Education & Solutions Ltd | Education | 2025 |
| Seven Heaven 1 Ltd | Extraterritorial | 2025 |
| Sewe Construction Ltd | Construction | 2024 |
| SFV Group Limited | Administrative & support | 2021 |
| SH Farriery Limited | Other services | 2014 |
| Shackleton Management Consulting Limited | Education | 2021 |
| Shaheen Kitchen Ltd | Hospitality | 2026 |
| Shakermaker Consultancy Ltd | Other services | 2017 |
| Shalom Nest Ltd | Real estate | 2021 |
| Shanaya Group Private Limited | Health & social care | 2024 |
| Sharons Cattery Ltd | Agriculture & fishing | 2025 |
| Sharp Auto Services (Bracknell) Limited | Wholesale & retail | 2003 |
| Shazza Media Ltd | Information & communication | 2022 |
| Shedload of Greens Limited | Agriculture & fishing | 2025 |
| Sheelz Cakes Ltd | Manufacturing | 2021 |
| Shibu & Co. Limited | Professional & scientific | 2007 |
| Shibu & Sons Ltd | Other services | 2020 |
| Shield Roof Properties Ltd | Real estate | 2025 |
| Shield Southern Ltd | Construction | 2012 |
| Shields Home Developments Limited | Construction | 2025 |
| Shine Bright Cleaning Co Ltd | Administrative & support | 2026 |
| Shine Theory Exteriors Limited | Administrative & support | 2025 |
| Shinydata Ltd | Information & communication | 2024 |
| Shirebrook Village NO.2 Residents Company Limited | Households | 1992 |
| Shivras Group Limited | Information & communication | 2025 |
| Shodai Ltd | Other services | 2021 |
| Shoe Shine Service Ltd | Wholesale & retail | 2013 |
| Shola Ajibade Ltd | Professional & scientific | 2011 |
| Shopimals Ltd | Wholesale & retail | 2025 |
| Shopion Ltd | Wholesale & retail | 2023 |
| Shopmed UK Ltd | Wholesale & retail | 2026 |
| Shopto.Net Limited | Information & communication | 2006 |
| Shorsoft Ltd | Real estate | 2023 |
| Shorts Agricultural Services Ltd | Agriculture & fishing | 1997 |
| Shorts Group (Asset Management) Limited | Financial services | 2019 |
| Shorts Group (Holdings) Limited | Financial services | 2019 |
| Shorts Group (ST George's Lane) Limited | Construction | 2019 |
| Shorts Group Limited | Water & waste | 1962 |
| Shorts Limited | Professional & scientific | 1998 |
| Shorts of Ascot Limited | Administrative & support | 1958 |
| Shorts Services Limited | Professional & scientific | 2004 |
| Shorts Timber Services (Datchet) Limited | Professional & scientific | 1998 |