| SORON2 Solutions Ltd | Health & social care | 2014 |
| Sortted Ltd | Professional & scientific | 2014 |
| Sorzano’S Plumbing & Construction Limited | Construction | 2020 |
| Sotiri Express Ltd | Transport & logistics | 2022 |
| Sound Distribution Group Ltd | Other services | 2019 |
| Sound Distribution Ltd | Other services | 2019 |
| South Midlands Developments Limited | Extraterritorial | 2003 |
| Southern Counties Event Caterers Ltd | Hospitality | 2024 |
| Southern Inkz Ltd | Other services | 2022 |
| Southwest Healthcare Services Limited | Public administration | 2025 |
| Sovereign Property Sourcing Limited | Real estate | 2023 |
| Sowa Accountancy Ltd | Professional & scientific | 2021 |
| Sozio UK Limited | Manufacturing | 1987 |
| SP Trans&Logistic Ltd | Wholesale & retail | 2021 |
| Space for Race Limited | Education | 2024 |
| Spackle Hygienic Limited | Administrative & support | 2024 |
| Spde Limited | Professional & scientific | 2024 |
| Specialist Car Storage Midlands Ltd | Transport & logistics | 2025 |
| Specialist Performance Cars Limited | Wholesale & retail | 2014 |
| Specialist Safety Solutions Limited | Administrative & support | 2011 |
| Spectra Wellingborough UK Ltd | Wholesale & retail | 2023 |
| Spectrum Fire (UK) Limited | Construction | 2003 |
| Spectrum Investment Holdings Ltd | Real estate | 2025 |
| Speedcheck Ltd | Other services | 2011 |
| Speedy Bubbles Ltd | Wholesale & retail | 2025 |
| Spellfame Karting Limited | Arts & recreation | 1999 |
| Spencer Duffy Limited | Construction | 2017 |
| Spencer Specialist Motors Limited | Wholesale & retail | 2025 |
| Sphero Limited | Professional & scientific | 2015 |
| Spice Fusion Indian Restaurant Wellingborough Limited | Hospitality | 2025 |
| Spice Fusion Wellingborough Limited | Hospitality | 2025 |
| Spice in Ltd | Hospitality | 2019 |
| Spicy Bitez Ltd | Hospitality | 2026 |
| Spike Innovations Ltd. | Manufacturing | 2024 |
| Spinney Brook Management Limited | Professional & scientific | 2008 |
| Spires & Squires Limited | Administrative & support | 2024 |
| Splendid Films (UK) Ltd | Information & communication | 1998 |
| Splice Films Ltd | Information & communication | 2016 |
| Split Second Films Ltd | Information & communication | 1990 |
| Spmo Services Ltd | Wholesale & retail | 2018 |
| Spog Property Limited | Real estate | 2021 |
| Spog Rural Limited | Agriculture & fishing | 2024 |
| Sports Performance Limited | Manufacturing | 2005 |
| Spot on Delivery Ltd | Transport & logistics | 2018 |
| Spray-Craft Coatings Limited | Manufacturing | 2001 |
| Sprint Hire Limited | Administrative & support | 2006 |
| Sprint Speed Couriers Limited | Transport & logistics | 2019 |
| SPS Service Car Repairs Ltd | Wholesale & retail | 2025 |
| SQ Motors Ltd | Wholesale & retail | 2025 |
| SQ Taxis Ltd | Transport & logistics | 2025 |
| Sqntech Limited | Information & communication | 2021 |
| SR Alam Consulting Ltd | Professional & scientific | 2025 |
| SRB Tech Ltd | Professional & scientific | 2025 |
| SRK Catering Group Ltd | Hospitality | 2024 |
| Sroya Ltd | Real estate | 2019 |
| SRSC23 Ltd | Real estate | 2025 |
| SS Fittings Ltd | Construction | 2020 |
| SS Kahlon Transport Ltd | Transport & logistics | 2023 |
| SS Property Maintenance UK Ltd | Construction | 2024 |
| Ss-Lvs Limited | Wholesale & retail | 2026 |
| SSB Creative LLP | | 2008 |
| Ssiap Ltd | Real estate | 2024 |
| SSJ Consulting Services Ltd | Professional & scientific | 2023 |
| ST Babs Limited | Transport & logistics | 2025 |
| ST James Ezekiel Investments Limited | Real estate | 2021 |
| ST Neots Self Store Limited | Real estate | 2017 |
| ST Peter's Community Enterprise Centre Limited | Other services | 2007 |
| ST Peters MLA Ltd | Real estate | 2024 |
| ST Steel Detailing Services Ltd | Construction | 2015 |
| ST. George (Mercia) Developments Limited | Real estate | 2002 |
| ST. Jude Care Homes Ltd | Health & social care | 2024 |
| Stacey Osborne Limited | Professional & scientific | 2018 |
| STAFF2DRIVE Ltd | Transport & logistics | 2024 |
| Stafford Renewable Energy Limited | Energy | 2013 |
| Stan Art & Design Ltd | Manufacturing | 2026 |
| Stanasa Architectural Steel & Aluminium Designs Ltd | Professional & scientific | 2023 |
| Standout Creative Ltd | Information & communication | 2025 |
| Stanhope Partnership Limited | Professional & scientific | 2005 |
| Stanley Mews (Wellingborough) Management Limited | Households | 2020 |
| Stanners Media Limited | Information & communication | 2023 |
| Stanton Cross Facility Management UK Ltd | Administrative & support | 2025 |
| Stanton Foods Limited | Wholesale & retail | 2022 |
| Stanwick Hand Car Wash Ltd | Administrative & support | 2024 |
| Stanwick Pet Spa Ltd | Other services | 2023 |
| Star Business Energy Limited | Energy | 2025 |
| Starinze Ltd | Health & social care | 2023 |
| Starline Haulage Ltd | Transport & logistics | 2025 |
| Starseed Care Ltd | Health & social care | 2025 |
| Start Over With Kindness Ltd | Wholesale & retail | 2024 |
| Startrucker Ltd | Transport & logistics | 2016 |
| Station Taxis Wellingborough Limited | Transport & logistics | 2020 |
| Staylo Services Limited | Administrative & support | 2025 |
| Steelhaus Limited | Manufacturing | 2019 |
| Stella Virtutis Ltd | Energy | 2025 |
| Stephanie Rumney Consultancy Ltd | Education | 2017 |
| Stephill Generators (Wellingborough) Limited | Extraterritorial | 1988 |
| Stephill Generators Limited | Manufacturing | 1985 |
| Sterling Installations Limited | Manufacturing | 1999 |
| Steve Chambers Accountants Ltd | Professional & scientific | 2026 |
| Steve Gill Logistics Ltd | Transport & logistics | 2015 |