| SSJ Trans Ltd | Transport & logistics | 2019 |
| SSL Plumbing & Heating (Midlands) Limited | Construction | 2025 |
| SSL Plumbing & Heating Limited | Construction | 2016 |
| Sstar Consulting Ltd | Administrative & support | 2011 |
| SSW Data & AI Ltd | Information & communication | 2024 |
| ST Andrew's Clay Coton Limited | Real estate | 2024 |
| ST Andrew's Healthcare | Health & social care | 2004 |
| ST Andrews Property Management Limited | Real estate | 1993 |
| ST Andrew’S Foundation for Mental Health | Health & social care | 2017 |
| ST Anne's and ST Elizabeth's Resource Centre CIC | Education | 2024 |
| ST Bonaventure Trust | Education | 2013 |
| ST Camillus Blackpool Limited | Hospitality | 2017 |
| ST Clair Investments Limited | Construction | 1996 |
| ST Clair Land & Developments LLP | | 2010 |
| ST Couriers Ltd | Transport & logistics | 2025 |
| ST Crispin Social Club Limited | Arts & recreation | 2016 |
| ST Crispins Local Centre Management Limited | Real estate | 2010 |
| ST Electrics Ltd | Construction | 2016 |
| ST Francis Healthcare Ltd | Health & social care | 2021 |
| ST Giles Park (Tattenhoe) Management Company Limited | Households | 2013 |
| ST Giles Physiotherapy Kettering Ltd | Other services | 2025 |
| ST Giles Physiotherapy Ltd | Other services | 2023 |
| ST Improvements Ltd | Construction | 2025 |
| ST Ives Consultancy Limited | Construction | 2022 |
| ST James Fish & Chips Limited | Hospitality | 2022 |
| ST James Kebab Ltd | Hospitality | 2024 |
| ST James Park Property Investments Limited | Construction | 2017 |
| ST James Pizza Ltd | Hospitality | 2024 |
| ST Judes Property Management Ltd | Real estate | 2018 |
| ST Kebab & Pizza Ltd | Hospitality | 2016 |
| ST Lawrence Court Limited | Real estate | 2000 |
| ST Lawrence Court RTM Company Limited | Households | 2023 |
| ST Margaret's View (Crick) Management Company Limited | Households | 2014 |
| ST Marys Practice Ltd | Health & social care | 2019 |
| ST Matthews (SB) Limited | Real estate | 2008 |
| ST Nuel Care Limited | Manufacturing | 2023 |
| ST Peter's Gardens Ltd | Real estate | 2019 |
| ST Peters Mede Management Company Limited | Households | 2009 |
| ST Rafael Healthcare Limited | Health & social care | 2023 |
| ST Sebastians Property Management Ltd | Real estate | 2018 |
| ST Thomas of Canterbury Cathedral Centre Limited | Hospitality | 2017 |
| ST Travel Ltd | Transport & logistics | 2012 |
| ST. David's Fish and Chips Ltd | Hospitality | 2023 |
| ST. David's Fish Bar Ltd | Hospitality | 2016 |
| ST. Edmunds Property Management Limited | Households | 2003 |
| ST. Giles Retreat LLP | | 2019 |
| ST. James Launderette Limited | Other services | 2002 |
| ST. J’S Properties Ltd | Real estate | 2026 |
| ST. Michael's Support & Care (Derby) Ltd | Other services | 2010 |
| ST. Nicholas AID Ltd | Health & social care | 2025 |
| St.Michael's Support Limited | Health & social care | 2016 |
| Staa London Ltd | Real estate | 2019 |
| Stabilised Pavements Limited | Administrative & support | 1996 |
| Stabilised Pavements UK Limited | Professional & scientific | 1995 |
| Stable & Wild Limited | Education | 2007 |
| Stable Accommodation Limited | Real estate | 2023 |
| Stable Minds Life Skills Limited | Other services | 2025 |
| Stachowiak Whisky Ltd | Wholesale & retail | 2026 |
| Stackr Truck Limited | Wholesale & retail | 2025 |
| Stadium Advisory Services Ltd | Professional & scientific | 2007 |
| Stadium Car Wash Ltd | Other services | 2023 |
| Stadium Simulator Ltd | Information & communication | 2025 |
| Stagar Express Ltd | Transport & logistics | 2022 |
| Stagar Services Ltd | Transport & logistics | 2025 |
| Stage Support Services Ltd | Administrative & support | 2006 |
| Stagger Inn Grantham Limited | Hospitality | 2013 |
| Stagshaw Property Ltd | Real estate | 2025 |
| Stainless Process Services Limited | Professional & scientific | 2018 |
| Stainless Solutions Limited | Professional & scientific | 2021 |
| Stainless Steel Solutions Ltd | Construction | 2008 |
| Stainsby Solutions Limited | Professional & scientific | 2016 |
| Stalks Communications Limited | Information & communication | 2025 |
| Stallion Black Ltd | Real estate | 2019 |
| Stallion Consulting Ltd | Wholesale & retail | 2023 |
| Stallion Immigration Ltd | Professional & scientific | 2024 |
| Stallone ADU Logistics Ltd | Transport & logistics | 2025 |
| Stallone Logistics Limited | Transport & logistics | 2016 |
| Stalsito Ltd | Professional & scientific | 2025 |
| Stample Limited | Construction | 2016 |
| STAN92 Ltd | Administrative & support | 2018 |
| Stand OUT Northamptonshire Limited | Administrative & support | 2017 |
| Standard Hygiene Environmental Services Ltd | Water & waste | 2017 |
| Standards Managed Ltd | Professional & scientific | 2022 |
| Standens Barn Supermarket Ltd | Wholesale & retail | 2022 |
| Standex Systems Limited | Wholesale & retail | 1991 |
| Stanford Scaffolding Limited | Construction | 1996 |
| Stanley Black & Decker UK Limited | Professional & scientific | 2009 |
| Stanley H Field Limited | Wholesale & retail | 2004 |
| Stanley Security and Cleaning Company Ltd | Administrative & support | 2019 |
| Stanley’S Landscapes Ltd | Administrative & support | 2024 |
| Stanmore Hill Limited | Real estate | 2020 |
| Stannard Financial Services Ltd | Professional & scientific | 2023 |
| Stansfield & Hoole LLP | | 2017 |
| Stanton Investments Limited | Real estate | 1996 |
| Stanton Property Developments Limited | Construction | 2014 |
| Stanton Property Holdings Limited | Real estate | 2014 |
| Stanton Residential Investments Limited | Real estate | 2015 |
| Stantone EV Ltd | Wholesale & retail | 2023 |
| Stantone Mechanical Handling Limited | Administrative & support | 1961 |
| Stantone Transport Ltd | Transport & logistics | 2023 |