| Strathcarrons Limited | Manufacturing | 2012 |
| Stratus Property Limited | Real estate | 2019 |
| Street Safe London Ltd | Health & social care | 2021 |
| Street Slice Ltd | Hospitality | 2025 |
| Stress Free Developments Ltd | Real estate | 2021 |
| Stribo Ltd | Professional & scientific | 2021 |
| Stride & Ride CIC | Transport & logistics | 2024 |
| Strimline Estate Services Ltd | Administrative & support | 2023 |
| Stringing 2000 Limited | Manufacturing | 2005 |
| Stronghold Security Systems Ltd | Construction | 2012 |
| Strongman Craig Holdings Ltd | Financial services | 2026 |
| Strongman Craig Properties Ltd | Real estate | 2024 |
| Strongman Holdings Ltd | Financial services | 2024 |
| Strongman Properties (Grange Road) Ltd | Real estate | 2024 |
| Struchkova-Dawson Ltd | Professional & scientific | 2015 |
| Struktures General Ltd | Professional & scientific | 2025 |
| Struktures Group Ltd | Professional & scientific | 2025 |
| Struktures HRB Ltd | Professional & scientific | 2025 |
| Stu's Barber Shop Limited | Other services | 2013 |
| Studentsblueboard Ltd | Education | 2016 |
| Studio 4 Limited | Professional & scientific | 2017 |
| Studio Carter Ltd | Professional & scientific | 2021 |
| Studio LH Ltd | Other services | 2010 |
| Studio Twelve Collection Ltd | Arts & recreation | 2025 |
| STUDIO27 Ladies Only Fitness & Wellness Ltd | Arts & recreation | 2025 |
| Studney Kirby Financial Planning Ltd | Financial services | 2012 |
| STW Pipe Work Services Limited | Construction | 2015 |
| Style Empire Salons Ltd | Other services | 2019 |
| Stylefrog Creative Ltd | Information & communication | 2012 |
| Styleseal Surfacing Ltd | Administrative & support | 2009 |
| Styleweb Content Management Limited | Information & communication | 2004 |
| Stylus Office Supplies Limited | Wholesale & retail | 2018 |
| Suada Corporation Ltd | Information & communication | 2020 |
| SUE Moorcroft Limited | Administrative & support | 2008 |
| Suena Limited | Hospitality | 2017 |
| Suena Properties Limited | Real estate | 2024 |
| Sugarbush AHJ Ltd | Hospitality | 2025 |
| Summer Brown Beauty Ltd | Other services | 2026 |
| Summit Design and Build Ltd | Construction | 2011 |
| Summit Site Solutions Ltd | Construction | 2025 |
| Summlott Services Limited | Administrative & support | 2008 |
| Sundance Holdings RA Ltd | Financial services | 2023 |
| Sundowner Limited | Hospitality | 1993 |
| Sunlightenergygb Limited | Manufacturing | 2025 |
| Sunny Investments Ltd | Real estate | 2018 |
| Sunseeker Windows Limited | Manufacturing | 1997 |
| Super-Frame Limited | Wholesale & retail | 2013 |
| Supernova Agencies Limited | Wholesale & retail | 2015 |
| Supervision and Audio Limited | Professional & scientific | 1974 |
| Supreme 27 Ltd | Financial services | 2021 |
| Supreme Weighing Services Limited | Administrative & support | 2009 |
| SUR Transport Ltd | Transport & logistics | 2025 |
| Sure-Can Limited | Manufacturing | 2002 |
| Sure-Foot Supports Limited | Extraterritorial | 1982 |
| Suresh Properties Limited | Real estate | 2024 |
| Surge Limited | Information & communication | 2017 |
| Surrey Innovations Limited | Administrative & support | 2015 |
| Surrounding Villages Builders Limited | Administrative & support | 2021 |
| Susie Berry Eventing Ltd | Agriculture & fishing | 2019 |
| Sustained Care Services Ltd | Administrative & support | 2021 |
| SV Food City Limited | Wholesale & retail | 2021 |
| SW WAX Melts Ltd | Wholesale & retail | 2025 |
| Swallow Court (Kettering) Management Limited | Households | 2001 |
| Swans Accommodations Ltd | Hospitality | 2026 |
| Swanseamark Limited | Real estate | 2021 |
| Swasth Ltd | Health & social care | 2022 |
| Swatini Ltd | Administrative & support | 2016 |
| Sweet Caroline Property Limited | Real estate | 2022 |
| Sweet Freedom Limited | Wholesale & retail | 2003 |
| Swift Cabs Ltd | Other services | 2021 |
| Swit Homes Ltd | Real estate | 2024 |
| SXY Trmp Ltd | Wholesale & retail | 2025 |
| Sycamore Forest Catering Ltd | Hospitality | 2022 |
| Synapsex Learning Ltd | Education | 2025 |
| Synapsys IQ Limited | Information & communication | 2025 |
| Syncro Logistics Ltd | Transport & logistics | 2018 |
| Synergy Electrical Services Ltd | Construction | 2019 |
| Sywell Safety Group Ltd | Public administration | 2026 |
| Szymon J. Limited | Administrative & support | 2025 |
| T & K Scaffolding Limited | | 1984 |
| T & L Developments Limited | Construction | 2009 |
| T Arthey Ltd | Professional & scientific | 2012 |
| T Creations Ltd | Wholesale & retail | 2020 |
| T Film Media Limited | Professional & scientific | 2022 |
| T J & S Aggregates Limited | Administrative & support | 2024 |
| T J B Driving Services Limited | Administrative & support | 2013 |
| T James Group Ltd | Financial services | 2025 |
| T Johnson Building Services Limited | Construction | 2022 |
| T M Construction (Northants) Limited | Construction | 2003 |
| T R Electrical (Northants) Limited | Construction | 2016 |
| T Trans Limited | Transport & logistics | 2018 |
| T&H3 Nails Spa Company Limited | Other services | 2021 |
| T&M Houlage Ltd | Transport & logistics | 2026 |
| T-Pads Cycling Limited | Manufacturing | 2022 |
| T. James (Electrical) Limited | Construction | 1962 |
| T. James (Special Projects) Limited | Professional & scientific | 2005 |
| T. James Holdings Limited | Financial services | 2019 |
| T.E Labyrinth Limited | Administrative & support | 2017 |
| T.H Higgins Ltd | Extraterritorial | 1939 |
| T.H.C. Selfstore Limited | Other services | 2002 |