| Sleeping Storm (Aiki) Limited | Education | 2021 |
| Sleepytiger Interactive Limited | Information & communication | 2015 |
| Sleuth Data Analytics Services Limited | Information & communication | 2018 |
| Slinfold Ltd | Real estate | 2023 |
| Slinfold Parish Cottages | Hospitality | 2014 |
| Slinfold Properties Limited | Real estate | 1999 |
| SLS Mvhr Limited | Construction | 2026 |
| SM Fencing Limited | Construction | 2025 |
| Small Batch Plastics Limited | Manufacturing | 1997 |
| Small Firms Accounts and Tax Ltd | Professional & scientific | 2004 |
| Small Town Ltd | Real estate | 2023 |
| Smart Ecom Ltd | Wholesale & retail | 2024 |
| Smart Fit Windows Ltd | Construction | 2022 |
| Smart-Eco Limited | Information & communication | 1996 |
| Smartshots Limited | Information & communication | 2004 |
| Smartwood Flooring Limited | Construction | 2003 |
| Smarty Inns Limited | Hospitality | 2013 |
| Smdg Coachworks Ltd | Wholesale & retail | 2018 |
| Smdg Performance Limited | Wholesale & retail | 2006 |
| Smdrilling Limited | Construction | 2025 |
| SME Media Group Ltd | Other services | 2023 |
| SMI Operations Limited | Professional & scientific | 2016 |
| Smiling Frog Ltd | Real estate | 2024 |
| Smith Gadd & Co LLP | | 2025 |
| Smith Property (Southern) Ltd | Real estate | 2024 |
| Smjv Ltd | Real estate | 2013 |
| SMN Sign & Print Limited | Manufacturing | 2013 |
| Smoking Olive Ltd | Hospitality | 2024 |
| Smotl Ltd | Information & communication | 2012 |
| SMP Consult Ltd | Real estate | 2024 |
| SMP Electrical Contractors Limited | Construction | 2014 |
| SMR Print Group Ltd | Manufacturing | 2021 |
| Smug Cat Ltd | Administrative & support | 2021 |
| Snack Shack Vends Limited | Hospitality | 2025 |
| Snow Grid Limited | Administrative & support | 2021 |
| Soar Medical UK Ltd | Health & social care | 2023 |
| Social Media Team Ltd | Professional & scientific | 2022 |
| Society for Promoting Chiropractic Education | Education | 2016 |
| SOL Sorella Limited | Manufacturing | 2026 |
| Solaris Systems Limited | Information & communication | 2005 |
| Solcad Technologies Ltd | Administrative & support | 2025 |
| Solent Group Holdings Limited | Financial services | 2018 |
| Solibra Logistics Services Limited | Transport & logistics | 2014 |
| Solid Silver Limited | Information & communication | 2017 |
| Solomon Harris Limited | Arts & recreation | 2024 |
| Solomon's Seal (Horsham) Management Company Limited | Households | 2017 |
| Solsteer Limited | Manufacturing | 2018 |
| Solve Social Value Limited | Information & communication | 2023 |
| Sommeil Consulting and Psychotherapy Ltd | Health & social care | 2022 |
| Sommelier Edit Ltd | Information & communication | 2023 |
| Songhurst Meadow Residents Association Limited | Households | 2019 |
| Sonic LH Rail Ltd | Construction | 2024 |
| Sons of Asgard Limited | Wholesale & retail | 2023 |
| Sophie's Studio Ltd | Education | 2025 |
| Sophisticated Medical Aesthetics Ltd | Other services | 2023 |
| South Aviation Training Services Ltd | Professional & scientific | 2023 |
| South Coast Polishing Ltd | Construction | 2019 |
| South Downs Audio Limited | Wholesale & retail | 2022 |
| South Downs MOT Centre Ltd | Wholesale & retail | 2021 |
| South Downs Strings Ltd | Arts & recreation | 2023 |
| South Downs Trust Limited | Financial services | 2022 |
| South East Signage Ltd | Manufacturing | 2023 |
| South East Tank Masters Limited | Construction | 2026 |
| South Lodge Advisory Limited | Professional & scientific | 2024 |
| South Sussex Contracting Limited | Construction | 2025 |
| South West Adventure Golf Limited | Arts & recreation | 2013 |
| South West Highways Limited | Construction | 1995 |
| Southampstead Developments Limited | Professional & scientific | 2008 |
| Southcore Automotive Ltd | Wholesale & retail | 2013 |
| Southdown Homes Ltd | Real estate | 2018 |
| Southern Coachworks Ltd | Wholesale & retail | 2015 |
| Southern Consultancy Services Limited | Professional & scientific | 2008 |
| Southern Counties Glass Holdings Limited | Professional & scientific | 2003 |
| Southern Counties Glass Limited | Manufacturing | 1999 |
| Southern Counties Home Improvements Ltd | Construction | 2026 |
| Southern Cranes & Access Ltd | Construction | 1997 |
| Southern Forgecraft Ltd | Manufacturing | 2024 |
| Southoak Properties Limited | Real estate | 2023 |
| Southward-Knightly Property Ltd | Real estate | 2019 |
| Southwark Care Ltd | Health & social care | 2025 |
| Southwater Cleaning and Security Ltd | Wholesale & retail | 2020 |
| Southwater Community Partnership C.I.C. | Other services | 2024 |
| Southwater Design Associates Limited | Professional & scientific | 2003 |
| Southwater Farm Partnership LP | | 2011 |
| Southwater Garage Services Ltd | Wholesale & retail | 2022 |
| Southwater Plumbing & Heating Ltd | Construction | 2023 |
| Souvenir Studios Limited | Arts & recreation | 2026 |
| Sovereign Estates (Sussex) Ltd | Real estate | 2019 |
| Soyga Limited | Information & communication | 2022 |
| SP Strategic Consultancy Limited | Professional & scientific | 2017 |
| Spa NET Europe Ltd | Wholesale & retail | 2020 |
| Space Business Innovation Ltd | Professional & scientific | 2013 |
| Space Rocket Ltd | Arts & recreation | 2000 |
| Spark Public Relations LLP | | 2007 |
| Spark Social Media Ltd | Professional & scientific | 2021 |
| Sparkes Paraplanning Ltd | Financial services | 2025 |
| Sparkling Stud Ltd | Agriculture & fishing | 2013 |
| Sparkzmedia Limited | Information & communication | 2006 |
| Sparr Developments Limited | Real estate | 2006 |
| Spatial Sciences Ltd | Professional & scientific | 2018 |