| School Business Management Ltd | Professional & scientific | 2009 |
| Scott + Story Limited | Other services | 2026 |
| Scripted Lives Ltd | Information & communication | 2023 |
| Seca Holdings Limited | Administrative & support | 2025 |
| Security Gates and Doors Ltd | Other services | 2018 |
| Selcuk and SON Ltd | Health & social care | 2023 |
| Serenity Park & Lakes Ltd | Financial services | 2023 |
| Shadow Telemetry Ltd | Manufacturing | 2015 |
| Shelby Construction Management Ltd | Construction | 2025 |
| Shepherd Outdoors (Explore, Learn, Live) Ltd | Education | 2025 |
| Sherwood Forest Fishery Ltd | Agriculture & fishing | 2024 |
| Shinn Racing Panels Ltd | Professional & scientific | 2025 |
| Shires Holdings Group Ltd | Construction | 2026 |
| Shreenika Catering Ltd | Hospitality | 2024 |
| Silly BOI Ltd | Hospitality | 2023 |
| Silver Sockets Limited | Manufacturing | 2023 |
| Silverace G D Ltd | Agriculture & fishing | 2021 |
| Simonpollendinesprivatechef Ltd | Hospitality | 2024 |
| Simply Investment Property Services Limited | Real estate | 2022 |
| Simply Wills Ltd | Professional & scientific | 2023 |
| Simplysips Limited | Manufacturing | 2021 |
| SIX Limes Limited | Agriculture & fishing | 2019 |
| SJS Motorsport Limited | Arts & recreation | 2015 |
| Sleep Space Hire Ltd | Hospitality | 2022 |
| Slowik Enterprises Limited | Construction | 2008 |
| Smal Schools Ltd | Real estate | 2018 |
| Smar Car Wash Ltd | Administrative & support | 2018 |
| Smarter Homes Group Limited | Extraterritorial | 2021 |
| Smarter Living Group Limited | Extraterritorial | 2021 |
| Smarter Living Homes Limited | Extraterritorial | 2021 |
| Smile International | Health & social care | 2015 |
| Smith London Ltd | Wholesale & retail | 2024 |
| Smith's of Bourne Limited | Hospitality | 2026 |
| SMV Contract Services Ltd | Administrative & support | 2017 |
| Soaroya Ltd | Wholesale & retail | 2026 |
| Social Impact Projects CIC | Professional & scientific | 2023 |
| Solar (Whitelands) Limited | Extraterritorial | 2020 |
| Solar Charging Developments Limited | Extraterritorial | 2019 |
| Solar Charging Limited | Energy | 2016 |
| Solar Steam Ltd | Energy | 2013 |
| Solgen Rentals Limited | Administrative & support | 2024 |
| Solo Publishing Limited | Extraterritorial | 1990 |
| Sonic and Spectral Technologies Limited | Information & communication | 2023 |
| Sophie Allport Limited | Wholesale & retail | 2007 |
| Sorella Limited | Wholesale & retail | 2017 |
| Sound Masters Limited | Information & communication | 2023 |
| Source Stamford Ltd | Other services | 2024 |
| SOURCE97 Ltd | Professional & scientific | 2026 |
| South Lincolnshire Academies Trust | Education | 2011 |
| South Lincs Trading Ltd | Wholesale & retail | 2025 |
| South Place Limited | Hospitality | 2023 |
| Southern African Traders Ltd | Wholesale & retail | 2019 |
| Southern Belle Ltd | Real estate | 2023 |
| Southfield Business Park Management Company Limited | Households | 2006 |
| Sovereign & SON Partners Limited | Professional & scientific | 2024 |
| SP Bespoke Systems Ltd | Information & communication | 2019 |
| Sparkle Mortgage and Protection Ltd | Financial services | 2017 |
| Specialist Education Support Services Ltd | Education | 2026 |
| Specialist Propertyworx Ltd | Real estate | 2025 |
| Spectrum Entertainment Ltd | Arts & recreation | 2013 |
| Sphnyx Ltd | Real estate | 2016 |
| Spindle Systems (UK) Ltd | Manufacturing | 2018 |
| Spinney Maintenance Company Limited | Administrative & support | 2007 |
| Spittlegate Farm Developments Limited | Construction | 2012 |
| Spot on Projects Limited | Wholesale & retail | 1982 |
| Sprouting Seeds Limited | Extraterritorial | 2000 |
| Squidge Ltd | Wholesale & retail | 2025 |
| SRD Estates Ltd | Real estate | 2025 |
| SRH Group Holdings Limited | Financial services | 2022 |
| SSF Plumbing Ltd | Construction | 2023 |
| ST John's LEA Management Company Limited | Households | 2001 |
| ST Milton Limited | Agriculture & fishing | 2019 |
| Stamford Drama and Music CIC | Education | 2023 |
| Stamford Interiors Limited | Construction | 2014 |
| Stamford Roofing Company Ltd | Construction | 2012 |
| Stamford UK Financial Ltd | Financial services | 2019 |
| Stanhay Webb Limited | Manufacturing | 2009 |
| Starkhorn Ltd | Information & communication | 2024 |
| Steady Media Films Limited | Information & communication | 2025 |
| Steve Broadbent Consulting Ltd | Professional & scientific | 2015 |
| Sths Consulting Ltd | Wholesale & retail | 2024 |
| Still Skills for Life Ltd | Education | 2023 |
| Stocks AG Limited | Manufacturing | 1977 |
| Stocks Wheel Limited | Professional & scientific | 1981 |
| Strange and Wright Recruitment Partners Ltd | Administrative & support | 2026 |
| Strickland Transport and Recycling Limited | Transport & logistics | 2025 |
| Strickland Transport Limited | Transport & logistics | 2013 |
| Strictly Automation Ltd. | Administrative & support | 2007 |
| Strictly Sports Ltd | Information & communication | 2019 |
| Stringers Property Ltd | Real estate | 2025 |
| Stts Arboricultural Group Ltd | Administrative & support | 2021 |
| Stuart Chambers Design and Drawing Services Limited | Professional & scientific | 1994 |
| Studio Woanya Ltd | Professional & scientific | 2025 |
| Successful Psychology Limited | Education | 2019 |
| Suft Group Limited | Manufacturing | 2025 |
| Sumac HR Consultancy Ltd | Professional & scientific | 2022 |
| Summit Management Ltd | Professional & scientific | 2025 |
| Suppliers Ltd | Administrative & support | 2015 |
| Sure Property Lets Ltd | Real estate | 2023 |
| Suremove Property Lawyers Limited | Administrative & support | 2012 |