| Stan Speed Limited | Transport & logistics | 2026 |
| Stan XXL Ltd | Transport & logistics | 2014 |
| Stanion Landscaping Limited | Administrative & support | 2026 |
| Stanley Transport Ltd | Transport & logistics | 2017 |
| Star Transport Ltd | Transport & logistics | 2014 |
| Starburst Interiors Limited | Wholesale & retail | 2021 |
| Starland Services Ltd | Construction | 2022 |
| Starline Property Management Ltd | Real estate | 2025 |
| Static Caravan Warranties Limited | Administrative & support | 2024 |
| Staywell Occupational Health Limited | Health & social care | 2015 |
| STD Limited | Transport & logistics | 2023 |
| Steambender Limited | Wholesale & retail | 2020 |
| Stefanescu Properties Ltd | Real estate | 2023 |
| Steff Limited | Transport & logistics | 2013 |
| Stellar Engineering Limited | Professional & scientific | 2012 |
| Stelux Ltd | Wholesale & retail | 2022 |
| Stephen Keenan Limited | Extraterritorial | 2008 |
| Stephenson Way Limited | Real estate | 2020 |
| Stephs Accessories Ltd | Wholesale & retail | 2025 |
| Sterling Assessment Services Limited | Education | 2010 |
| Stewarts & Lloyds (Corby) Rugby Football Club Limited | Arts & recreation | 2013 |
| Stewarts & Lloyds Football Club Limited | Arts & recreation | 2019 |
| Stewarts & Lloyds Sports Club Limited | Arts & recreation | 2012 |
| Stik-Chik Agency Limited | Administrative & support | 2006 |
| Stjepanovic Civils Limited | Construction | 2026 |
| Stonehouse Commercial Ltd | Construction | 2017 |
| Stonerush Limited | Hospitality | 2022 |
| Stoneygate International Ltd | Education | 2020 |
| STR Civils Ltd | Construction | 2021 |
| Strachan Accounting Limited | Extraterritorial | 2024 |
| Stratos Control Systems Limited | Professional & scientific | 1995 |
| Strazdi Ltd | Transport & logistics | 2016 |
| Strickland & Co Accountants Limited | Professional & scientific | 2019 |
| Strides Buffets Limited | Hospitality | 2012 |
| Structura Partners Limited | Professional & scientific | 2022 |
| Stuart House Management Company Limited | Real estate | 1988 |
| Stuart Lacey & Associates Ltd | Financial services | 2013 |
| Studfall Limited | Real estate | 2013 |
| Studio 21 Beauty and Aesthetics Ltd | Other services | 2024 |
| Studio B54 Limited | Information & communication | 2016 |
| Studio One Group Ltd | Wholesale & retail | 2025 |
| Studio Seren Ltd | Wholesale & retail | 2023 |
| Subway Kettering Ltd | Hospitality | 2015 |
| Sud-Mar Ltd | Transport & logistics | 2025 |
| Sugar Crush Confectionery Ltd | Wholesale & retail | 2021 |
| Sugarbabybylily Ltd | Wholesale & retail | 2025 |
| Sulby Hall Farm Limited | Agriculture & fishing | 2019 |
| Sulgrave Drive 1956 Limited | Extraterritorial | 2014 |
| Sun Studio Rentals Limited | Administrative & support | 2025 |
| Sun%Shine Limited | Health & social care | 2023 |
| Sunfilm (UK) Limited | Manufacturing | 2010 |
| Sunflower Office Limited | Information & communication | 2025 |
| Sunny's Garden Projects Ltd | Transport & logistics | 2025 |
| Sunray Games Ltd | Arts & recreation | 2025 |
| Sunseeker Travel Group Limited | Other services | 2014 |
| Supacolour UK Ltd | Professional & scientific | 2019 |
| Supbox Ltd | Wholesale & retail | 2025 |
| Superbikes Advocates Racing Limited | Wholesale & retail | 2025 |
| Superfos Tamworth Limited | Professional & scientific | 1966 |
| Supertechpc Ltd | Wholesale & retail | 2026 |
| Support Rays Limited | Health & social care | 2016 |
| Supportneedsjm Limited | Health & social care | 2013 |
| Suprenas Ltd | Other services | 2024 |
| Sure Load Limited | Transport & logistics | 2025 |
| Surgal Properties Limited | Hospitality | 2014 |
| Sustainable Lean Business Improvements Limited | Professional & scientific | 2017 |
| SV Pizza Ltd | Hospitality | 2021 |
| SVR Fire and Security Ltd | Construction | 2024 |
| Swan Innovations Limited | Construction | 2007 |
| Swan Valley Solutions Ltd | Professional & scientific | 2015 |
| Swarnkkar Consultancy Limited | Information & communication | 2017 |
| Sweet Chimney Cake Ltd | Hospitality | 2021 |
| Swider Trans Limited | Transport & logistics | 2015 |
| Swillsneakers Ltd | Wholesale & retail | 2021 |
| Sycamore Garden Solutions Ltd | Arts & recreation | 2025 |
| Sycamore Properties Group Ltd | Hospitality | 2025 |
| Sylogistic Ltd | Construction | 2022 |
| Synergy Packaging Solutions Limited | Manufacturing | 2001 |
| Syntec Systems Limited | Information & communication | 2012 |
| Syshez Services Ltd | Extraterritorial | 2024 |
| Sysonby Lodge (Melton Mowbray) Management Company Limited | Households | 2024 |
| Sysonby Lodge Freehold Limited | Households | 2024 |
| System Edstrom UK Ltd | Manufacturing | 1987 |
| Systembox Ceramic Supplies Limited | Professional & scientific | 2007 |
| Sywell Grange Limited | Construction | 2018 |
| Sywell Investments Limited | Real estate | 2011 |
| Sywell Land Limited | Real estate | 2005 |
| Sywell Projects Limited | Construction | 2011 |
| Sywell Securities Limited | Real estate | 2002 |
| Szczepan Ltd | Wholesale & retail | 2017 |
| Szwagier Ltd | Wholesale & retail | 2025 |
| T J & N Holdings Limited | Real estate | 2009 |
| T J G Logistics Limited | Transport & logistics | 2009 |
| T&Gr Travel Limited | Administrative & support | 2011 |
| T&J Victorious Ltd | Health & social care | 2020 |
| T&M Mortgages & Financial Planning Limited | Financial services | 2024 |
| T-Lab Limited | Wholesale & retail | 2006 |
| T.Forsell & SON (Properties) Limited | Real estate | 1949 |
| T.Jackson Electrical Services Ltd | Construction | 2022 |
| TAD Transport Ltd | Administrative & support | 2018 |