| Sjam Limited | Administrative & support | 2007 |
| Sjbaxter Transport Ltd | Transport & logistics | 2025 |
| SJC Trailers Limited | Manufacturing | 2010 |
| Skaters (Wisbech) Limited | Arts & recreation | 2014 |
| Skaters Properties Limited | Real estate | 2018 |
| Skeels Engineering Limited | Professional & scientific | 2025 |
| Skilled Resources Limited | Construction | 1997 |
| Sky City Property Ltd | Real estate | 2021 |
| Slace Inspection Services Ltd | Professional & scientific | 2013 |
| Slicas Haulage Ltd | Transport & logistics | 2026 |
| SLM Engineering (Cambs) Ltd | Professional & scientific | 2025 |
| SLR Electrical and Maintenance Ltd | Construction | 2017 |
| SLR Electrical Services Ltd | Construction | 2026 |
| SLR Property Development Ltd | Construction | 2026 |
| Slurp Beverages Ltd | Manufacturing | 2024 |
| SM International Limited | Wholesale & retail | 2024 |
| SM Transport Services Ltd | Transport & logistics | 2022 |
| Smart Property Renovations Limited | Real estate | 2024 |
| Smart Service Way Ltd | Information & communication | 2023 |
| Smart Trans 2020 Ltd | Transport & logistics | 2020 |
| Smash Boss Ltd | Hospitality | 2025 |
| Smeeth Group Limited | Financial services | 2026 |
| SMH Plastering Ltd | Construction | 2019 |
| Smiley Booth Essex Ltd | Professional & scientific | 2016 |
| Smilte Ltd | Transport & logistics | 2019 |
| Smith Percy Ltd | Real estate | 2013 |
| Smith Rooke Investments Ltd | Administrative & support | 2019 |
| Smithdon Developments Ltd | Construction | 2016 |
| Smithee & Sons Electrical Limited | Construction | 2006 |
| SML Rigging Services Ltd | Transport & logistics | 2019 |
| Smtm Capital Limited | Information & communication | 2022 |
| SN & J Construction Ltd | Construction | 2024 |
| SN Engineering Services Limited | Manufacturing | 2017 |
| Snacksy Candy Ltd | Wholesale & retail | 2025 |
| Snappy Software Solutions Ltd | Information & communication | 2020 |
| Social Research Limited | Education | 2015 |
| Software Farm Limited | Information & communication | 2026 |
| Somers House Ltd | Other services | 2013 |
| Somers Road Properties Limited | Real estate | 2011 |
| Somerset Farm (East Anglia) Ltd | Agriculture & fishing | 2012 |
| Sourcing Consulting Limited | Public administration | 2011 |
| South Engineering (Wisbech) Limited | Manufacturing | 2023 |
| South Nottinghamshire Property Co. Limited | Construction | 1972 |
| South Pacific Agencies (UK) Limited | Transport & logistics | 2009 |
| South West Traffic Management Limited | Construction | 2025 |
| South Wootton Consortium LLP | | 2016 |
| SP Developments (Norfolk) Limited | Real estate | 2006 |
| SP. Jack Ltd | Transport & logistics | 2010 |
| Spacemancodes Ltd | Information & communication | 2019 |
| Spalding Glass & Construction Limited | Construction | 2009 |
| Sparrow Consortium Limited | Professional & scientific | 2007 |
| Sparrowhawk Way 1975 Limited | Extraterritorial | 2014 |
| SPC Holdings EA Ltd | Real estate | 2021 |
| Speak Loud Community Interest Company | Health & social care | 2024 |
| Special Building Projects Ltd | Construction | 2012 |
| Speed Stacks (UK) Ltd | Wholesale & retail | 2018 |
| SPI UK Services Limited | Manufacturing | 2024 |
| Spice Market .Wisbech Ltd | Wholesale & retail | 2024 |
| Spices India Private Limited | Wholesale & retail | 2021 |
| Spilsby Care Ltd | Health & social care | 2014 |
| Spinal Enterprises Ltd | Wholesale & retail | 2024 |
| Spiral Bookkeeping Ltd | Professional & scientific | 2021 |
| Spiral Elevator Ltd | Manufacturing | 2018 |
| Spire Dental Limited | Financial services | 2023 |
| Spire View Advisory Limited | Professional & scientific | 2026 |
| Spitzer Eurovrac U.K. Limited | Wholesale & retail | 2004 |
| SPORT2DAY Ltd | Education | 2022 |
| Sportec UK Ltd | Manufacturing | 2022 |
| Sports and Leisure (Wisbech) Limited | Hospitality | 2019 |
| Sports Turf Specialists Ltd | Administrative & support | 2023 |
| Spotless Commercial Cleaning (UK) Limited | Administrative & support | 2014 |
| SPR (East Anglia) Limited | Agriculture & fishing | 2004 |
| Spr-Services Limited | Manufacturing | 2021 |
| Sprint E-Logistics Limited | Administrative & support | 2011 |
| Sprint Logistics (Northants) Limited | Transport & logistics | 2020 |
| Sprint Logistics Holdings Limited | Transport & logistics | 2017 |
| Sprint Logistics Limited | Transport & logistics | 1991 |
| SR Joinery & Furniture Company Limited | Manufacturing | 2025 |
| SRP Security Systems (Fens) Ltd | Administrative & support | 2023 |
| ST & T Consultancy Ltd | Information & communication | 2008 |
| ST Augustines Road Property Management Company Limited | Households | 2016 |
| ST Mary's Estates Limited | Real estate | 2007 |
| ST Marys Auto Centre Limited | Wholesale & retail | 2014 |
| ST. Marks Road Gorefield Residents Limited | Water & waste | 1996 |
| Stag Automotive Limited | Manufacturing | 2024 |
| Stage Acts Limited | Arts & recreation | 2024 |
| Stanford Drives & Patios Ltd | Construction | 2025 |
| Stanton Farms Developments Limited | Financial services | 2023 |
| Stanton Farms Holdings Limited | Financial services | 2021 |
| Stanton Farms Limited | Arts & recreation | 1975 |
| Star Mobile Ltd | Wholesale & retail | 2023 |
| Stark Construction Ltd | Construction | 2021 |
| Starlight Theatrical Ltd | Manufacturing | 2022 |
| Starz Fostering C.I.C. | Health & social care | 2019 |
| Staska Transport Limited | Transport & logistics | 2026 |
| Stasports Ltd | Financial services | 2011 |
| Stay Smart Ltd | Manufacturing | 2018 |
| Steakery Trading Ltd | Real estate | 2014 |
| Steinbauer Tuning Technologies UK Ltd | Wholesale & retail | 2007 |
| Stellar Staffing Ltd | Administrative & support | 2025 |