| Scorpion Ventures Ltd | Households | 2026 |
| Scott and Steel Limited | Construction | 2024 |
| Scott Barlow Plumbing & Heating Ltd | Construction | 2011 |
| Scott Heating and Ventilation Limited | Construction | 1975 |
| Scott Hydrofoils Limited | Professional & scientific | 2019 |
| Scott Properties (Thrapston) LLP | | 2019 |
| Scotts Haulage (1991) Ltd | Transport & logistics | 2008 |
| Screen School UK Ltd | Arts & recreation | 2023 |
| Sculpted by Demi Ltd | Other services | 2026 |
| Sculpted Earth Landscaping Ltd | Administrative & support | 2025 |
| SD & RJ Services Ltd | Wholesale & retail | 2023 |
| SD Selects Ltd | Wholesale & retail | 2026 |
| SDC Innovation Ltd | Information & communication | 2015 |
| SDN Laser Studio Ltd | Other services | 2026 |
| Sdpco Ltd | Hospitality | 2026 |
| SE Fibre Supplies Ltd | Wholesale & retail | 2025 |
| Sea & Shine Limited | Transport & logistics | 2025 |
| Sea and Skye Limited | Extraterritorial | 2017 |
| Sea of Support CIC | Administrative & support | 2025 |
| Seadog Coastal Ltd | Real estate | 2017 |
| Seagrave Decorations Limited | Construction | 2002 |
| Seagrave Inspection Services Limited | Construction | 2006 |
| Seagrave Projects Limited | Extraterritorial | 2017 |
| Seal Assured Group Ltd | Administrative & support | 2022 |
| Seal Assured Roofing Ltd | Construction | 2021 |
| Seamarks Ltd | Professional & scientific | 2025 |
| Searches UK Limited | Administrative & support | 2008 |
| Seasalt Energy Limited | Administrative & support | 2016 |
| Seasoned Purchasing Limited | Professional & scientific | 2003 |
| Seaview Enterprises Limited | Financial services | 2020 |
| Seaview Retreat Limited | Hospitality | 2017 |
| Sebpol Motors Limited | Wholesale & retail | 2024 |
| Seckloe 186 Limited | Real estate | 2003 |
| Seckloe 297 Limited | Professional & scientific | 2006 |
| Secure Technology Solutions Ltd | Administrative & support | 2012 |
| Securities Finance International Limited | Professional & scientific | 1995 |
| SEE Beyond the Pink Limited | Information & communication | 2013 |
| Seedhub Ltd | Administrative & support | 2017 |
| SEL Golf Ltd | Wholesale & retail | 2023 |
| Sela Flexi Ltd | Administrative & support | 2023 |
| Select Motor Company (Kettering) Limited | Wholesale & retail | 2004 |
| Selecta Events Ltd | Arts & recreation | 2023 |
| Selvakumars Ltd | Health & social care | 2017 |
| Senjef Care Limited | Health & social care | 2019 |
| Senjef Retail Ltd | Wholesale & retail | 2011 |
| Sense TMR Ltd | Professional & scientific | 2020 |
| Sentry Sprinkler Protection Limited | Public administration | 2022 |
| Separate Solutions Limited | Professional & scientific | 1997 |
| Serendipity Psychology Services Ltd | Health & social care | 2017 |
| Serenity - SET Apart Ltd | Health & social care | 2026 |
| Settlers Engineering Services Ltd | Professional & scientific | 2022 |
| Seven Cedars Ltd | Information & communication | 2012 |
| Seven Star Automotive Ltd | Administrative & support | 2026 |
| Sevenone Technologies Ltd | Information & communication | 2024 |
| SEVENTY9 Creative Limited | Information & communication | 2017 |
| SEVENTY9 Digital Ltd | Information & communication | 2019 |
| Severin Art Ltd | Extraterritorial | 2024 |
| Severus Engineering & Construction Ltd | Construction | 2025 |
| Sferle Construction Ltd | Construction | 2019 |
| SFW Electrical Limited | Construction | 2024 |
| SGH Agri Services Limited | Administrative & support | 2021 |
| SH Defleet Services Ltd | Wholesale & retail | 2024 |
| Shackleton Healthcare Ltd | Health & social care | 2018 |
| Shah Transport Ltd | Transport & logistics | 2013 |
| Shah Tyres Ltd | Wholesale & retail | 2024 |
| Shalom Care Group Ltd | Health & social care | 2021 |
| Shard Commercial Limited | Construction | 2019 |
| Sharnold Limited | Manufacturing | 1970 |
| Sharpys Barbers Limited | Other services | 2014 |
| SHASA2 Ltd | Health & social care | 2014 |
| Shava Health Care Ltd | Health & social care | 2022 |
| Shearforce Holdings Ltd | Financial services | 2024 |
| Shearforce Ltd | Manufacturing | 1998 |
| Shearforce Manufacturing Limited | Manufacturing | 2007 |
| Sheena's Skincare & Aesthetics Ltd | Other services | 2024 |
| Shefarro Limited | Wholesale & retail | 2026 |
| Shegxy Music International Limited | Information & communication | 2025 |
| Shep PR & Comms Ltd | Professional & scientific | 2020 |
| Sherwood Construction Limited | Construction | 2001 |
| Shift Actions (UK) Limited | Professional & scientific | 2018 |
| Shiloh Integrative Care Limited | Transport & logistics | 2023 |
| Shilpa Shebu Lukose Ltd | Health & social care | 2015 |
| Shimmer Cleaning and Maintenance Ltd | Administrative & support | 2024 |
| Shimmer Maintenance Services Ltd | Financial services | 2026 |
| Shine! Arts and Well-Being CIC | Education | 2022 |
| Shiny Garage Ltd | Wholesale & retail | 2026 |
| Shipway & Co. Limited | Professional & scientific | 2003 |
| Shire Electrical Limited | Construction | 2013 |
| Shire Kings Fitness Solutions Ltd | Administrative & support | 2017 |
| Shire Property Rentals (UK) Limited | Real estate | 2019 |
| Shire Security Limited | Construction | 1996 |
| Shireway Properties Ltd | Real estate | 2012 |
| Shollys Ltd | Hospitality | 2025 |
| Shop and Wash Car Wash Ltd | Other services | 2021 |
| Shop Locally Ltd | Wholesale & retail | 2023 |
| Shopfusion Ltd | Other services | 2011 |
| Shout Events Limited | Other services | 2017 |
| Show Time Events Group (Northern) Limited | Professional & scientific | 2020 |
| Show Time Events Group Limited | Arts & recreation | 2016 |
| Showline Support Ltd | Administrative & support | 2024 |