| Ssecam Community Interest Company | Other services | 2024 |
| ST Catherine's Grange Management Company Limited | Real estate | 2015 |
| ST Cuthberts Estates Limited | Real estate | 2017 |
| ST Cuthberts Fine Papers Limited | Manufacturing | 2012 |
| ST Mary's Court ELY Management Company Ltd | Households | 2015 |
| ST. Botolphs Road Residents Company Ltd | Households | 2019 |
| ST1 Consulting Limited | Professional & scientific | 2008 |
| ST1 Group Limited | Financial services | 2016 |
| ST1 Pre-Contract Services Limited | Other services | 2016 |
| Stable Block Management Company Limited | Administrative & support | 1987 |
| Stableford Close Management Company Limited | Real estate | 2018 |
| Stack Chasers UK Limited | Wholesale & retail | 2026 |
| Stacked & Loaded Doddington Ltd | Hospitality | 2024 |
| Stackhouse(Lwj)Watering Hole Limited | Hospitality | 2025 |
| Standen Engineering Group Limited | Financial services | 2021 |
| Standen Engineering Limited | Manufacturing | 2001 |
| Standen Property Limited | Real estate | 2001 |
| Stanfield Consultants Ltd | Professional & scientific | 2018 |
| Staploe Education Trust | Education | 2011 |
| Star Properties Eastern Ltd | Real estate | 2025 |
| Star Venture Property Ltd | Real estate | 2022 |
| Stardatacomms Limited | Professional & scientific | 2025 |
| Stars House of Beauty Ltd | Other services | 2025 |
| Station Approach Road (Coulsdon) Management Company Limited | Households | 2014 |
| Stay Section Ltd | Real estate | 2025 |
| Stearns Kilby Trading Limited | Hospitality | 2012 |
| Stell Commercial Consulting Limited | Professional & scientific | 2025 |
| Stellea Ltd | Health & social care | 2020 |
| Stem Brickwork and Landscapes Ltd | Construction | 2025 |
| Steven Layn (Holdings) Limited | Professional & scientific | 1992 |
| Stevens Belting Limited | Manufacturing | 2010 |
| Stevens Family Holdings Limited | Financial services | 2026 |
| Stevens Group Holdings Limited | Financial services | 2025 |
| Stevenson Tree Services Ltd | Administrative & support | 2012 |
| Steve’S Coal and Aggregates Limited | Wholesale & retail | 2026 |
| Stewart & Wisbey Limited | Wholesale & retail | 2002 |
| Stick Therapeutics Limited | Professional & scientific | 2026 |
| Stillaway Holdings Limited | Financial services | 2010 |
| Stimsons Tech Ltd | Wholesale & retail | 2026 |
| Stonerock Holdings Limited | Financial services | 2020 |
| Stonewall Media Ltd | Administrative & support | 2020 |
| Store Easy Limited | Construction | 1992 |
| Stourbridge House (Cambridge) Management Company Limited | Households | 1998 |
| Stowbridge Moorings Ltd | Real estate | 2013 |
| Strainworks Limited | Manufacturing | 2026 |
| Strandmill Limited | Financial services | 1993 |
| Strange Goose Ltd | Information & communication | 2024 |
| Stratech Scientific Limited | Professional & scientific | 1983 |
| Strategic Accounts Limited | Professional & scientific | 2019 |
| Strategic IT Ltd | Other services | 2023 |
| Strategic Leadership Solutions Ltd | Professional & scientific | 2026 |
| Stratxmedia Ltd | Professional & scientific | 2024 |
| Streetlight Media Representation Ltd | Professional & scientific | 2025 |
| Stretham Storage Ltd | Transport & logistics | 2016 |
| Stuart Knott Ltd | Information & communication | 2019 |
| Studio 3 ELY Ltd | Other services | 2011 |
| Studio Nova Ltd | Professional & scientific | 2021 |
| Studio US Cambridge Ltd | Professional & scientific | 2025 |
| Studioscape Garden Studios Ltd | Construction | 2026 |
| Subsidy Ltd | Wholesale & retail | 2026 |
| Suburban Windows Limited | Manufacturing | 2014 |
| Sudereli Ltd | Real estate | 2024 |
| Sunflower Group Limited | Agriculture & fishing | 2011 |
| Sunrise Shutters and Blinds Ltd | Households | 2008 |
| Suparoof Cambridge Limited | Construction | 1986 |
| Supastudios Ltd | Education | 2023 |
| Superior Commercial Cleaning Ltd. | Administrative & support | 2020 |
| Supplysection Ltd | Administrative & support | 2022 |
| Surf Style Ltd | Information & communication | 2004 |
| Surge Notify Ltd | Administrative & support | 2023 |
| Surindia Ltd | Information & communication | 2023 |
| Sutton CB Ltd | Other services | 2021 |
| Sutton Vehicle Transport Ltd | Other services | 2024 |
| Swahili Summers Ltd | Wholesale & retail | 2024 |
| Sweet Ally Scoops Limited | Hospitality | 2015 |
| Sweet Street Treats Ltd | Manufacturing | 2020 |
| SWP Group Limited | Professional & scientific | 1952 |
| SWP Property Holdings Limited | Professional & scientific | 1983 |
| SWP Property Investment Company Ltd | Financial services | 2019 |
| Sybil Tech Ltd | Information & communication | 2022 |
| Symbolics I-Commerce Ltd | Wholesale & retail | 2017 |
| Symonds Construction Ltd | Construction | 2021 |
| Symptech Limited | Information & communication | 2018 |
| Synsensia Ltd | Professional & scientific | 2016 |
| Synthetix Ltd | Information & communication | 2001 |
| Systability Ltd | Information & communication | 2000 |
| T and E Grant and SON Ltd | Wholesale & retail | 2016 |
| T Clennell Services Ltd | Manufacturing | 2025 |
| T H Tree Surgery Ltd | Agriculture & fishing | 2014 |
| T J D Spraying and Decorations Ltd | Construction | 2022 |
| T J Kent Racing Ltd | Arts & recreation | 2019 |
| T R Constable Carpentry & Construction Limited | Manufacturing | 2021 |
| T Stays Group Limited | Construction | 2025 |
| T Underwood (Engineering & Refrigeration) Limited | Manufacturing | 2007 |
| T V Trading Limited | Wholesale & retail | 2016 |
| T W Electrical (ELY) Limited | Construction | 2012 |
| T&D Contract Management Ltd | Professional & scientific | 2022 |
| T&D Projects Ltd | Real estate | 2020 |
| T&L Consulting Limited | Professional & scientific | 2016 |
| T&T Accounting Ltd | Professional & scientific | 2023 |