| S W Steel Trading Ltd | Manufacturing | 2021 |
| S.E.T. Electrical Contractors Limited | Construction | 2006 |
| Saddlebrook (Holdings) Limited | Financial services | 2019 |
| Safe Haven Care Home and Lodges Limited | Administrative & support | 2010 |
| Saray Fast Food Ltd | Hospitality | 2024 |
| Sentosa Consultancy Limited | Professional & scientific | 2023 |
| Seren Installs Ltd | Construction | 2015 |
| Shaun Harris Refrigeration Services Limited | Wholesale & retail | 2024 |
| Shineology Detailing Ltd | Wholesale & retail | 2021 |
| Sigma Manufacturing Limited | Manufacturing | 1996 |
| Silver Horse Consulting Ltd | Wholesale & retail | 2014 |
| Simpanda. Ltd | Information & communication | 2009 |
| SIX Darlings Ltd | Real estate | 2023 |
| Skyline Properties Limited | Real estate | 1997 |
| Slate and Sign Crafts Ltd | Wholesale & retail | 2024 |
| Snug Housing Limited | Real estate | 2017 |
| Solace Property Group Ltd | Administrative & support | 2019 |
| Solace Stays Ltd | Real estate | 2020 |
| Soundwave Studios Ltd | Manufacturing | 2025 |
| South Wales Care Group Ltd | Health & social care | 2023 |
| South Wales Disc Clinics Limited | Health & social care | 2025 |
| SOV Holdings Ltd | Financial services | 2019 |
| SOV Print Limited | Manufacturing | 2013 |
| Spear Auto Services Ltd | Wholesale & retail | 2018 |
| Spincom Haulage Limited | Transport & logistics | 1999 |
| Splash of Glass Ltd | Wholesale & retail | 2016 |
| Sprinkler System Solutions Ltd | Construction | 2018 |
| Staples Properties Limited | Real estate | 2025 |
| Star Linen UK Ltd | Wholesale & retail | 2016 |
| Star-Fusion Ltd | Administrative & support | 2016 |
| Starline Express Limited | | 2000 |
| Sub-Zero Refrigeration and Airconditioning Limited | Manufacturing | 2015 |
| Supastrikers Cascade Ltd | Arts & recreation | 2021 |
| Suphansa Sushi Ltd | Wholesale & retail | 2025 |
| T Wildflowers Ltd | Wholesale & retail | 2024 |
| T.Q. Finance Limited | Financial services | 1996 |
| Tanner 1966 Limited | Extraterritorial | 2014 |
| TDS Plumbing Contractors Limited | Construction | 2024 |
| THE Cheesecake Lady Ltd | Manufacturing | 2020 |
| THE Dress Boss Studio Ltd | Wholesale & retail | 2022 |
| THE Forge Ice & Heat Ltd | Other services | 2025 |
| THE Mindworks LAB Ltd | Health & social care | 2026 |
| THE Reno Project Ltd | Real estate | 2018 |
| THE Screwed Limited | Wholesale & retail | 2021 |
| THE Shifa Apothecary Ltd | Manufacturing | 2026 |
| THE Student Essentials Company Limited | Wholesale & retail | 2021 |
| THE Vaults Cafe Bar Ltd | Hospitality | 2025 |
| THE Wedding House Ltd | Wholesale & retail | 2018 |
| THE Wonky Bars Ltd | Hospitality | 2015 |
| TIR Tawel CIC | Health & social care | 2025 |
| TJ Edmunds Limited | Administrative & support | 2026 |
| TM Vehicle Sales Ltd | Wholesale & retail | 2025 |
| Toma Renovations Ltd | Construction | 2017 |
| Town Square Spaces Ltd | Administrative & support | 2017 |
| Townsq Support Limited | Wholesale & retail | 2021 |
| Tracy Rawlings Legal Services for Children | Professional & scientific | 2016 |
| Trgsports Limited | Arts & recreation | 2019 |
| Trident Drilling Ltd | Construction | 2026 |
| TY Hiraeth Properties Ltd | Extraterritorial | 2023 |
| Upton Upon Severn Folk Dance and Song Society | Arts & recreation | 2001 |
| UTR Developments Limited | Professional & scientific | 2014 |
| Valley PC Limited | Information & communication | 2003 |
| Valley Satellites Ltd | Information & communication | 2025 |
| Values in Care (Holdings) Limited | Administrative & support | 2010 |
| Vantastec Employee Ownership Trustee Limited | Professional & scientific | 2023 |
| Viner Earwax Removal Ltd | Health & social care | 2026 |
| VIP Oven Cleaning Ltd | Administrative & support | 2025 |
| VR VIZ Ltd | Professional & scientific | 2019 |
| Vulpes Estates Limited | Real estate | 2011 |
| VVD Consulting Limited | Professional & scientific | 2013 |
| W V Groundworks Ltd | Professional & scientific | 2017 |
| W&W Signature Spaces Ltd | Construction | 2026 |
| Wakefield and Co. Properties Ltd | Real estate | 2021 |
| Walsh Flooring Ltd | Construction | 2026 |
| Webs Away Cleaning Services Ltd | Administrative & support | 2025 |
| Welsh International Rally Limited | Arts & recreation | 2005 |
| Whichicon Limited | Information & communication | 2012 |
| Will's Rigging Limited | Information & communication | 2021 |
| WJP Brickwork and Construction Limited | Construction | 2026 |
| WPY Limited | Administrative & support | 2022 |
| WRS Consulting Ltd | Information & communication | 2015 |
| Y Caban/The Cabin CYF. | Hospitality | 2019 |
| Ystrad Mynach DRY Cleaning Limited | Other services | 2025 |
| Ystrad Mynach Ltd | Hospitality | 2025 |
| Zener Electrical Services Ltd | Construction | 2013 |