| Skirrid Employment Services Limited | Administrative & support | 2017 |
| Skylark Defence Limited | Manufacturing | 2025 |
| SL Properties Investments Ltd | Real estate | 2025 |
| Sleep Athletic Ltd | Health & social care | 2022 |
| Smart Heating Solutions (SW ) Ltd | Construction | 2023 |
| Smartbuild Energy Ltd | Construction | 2025 |
| SME Micro Solutions Ltd | Financial services | 2024 |
| SME Microsaver Limited | Administrative & support | 2023 |
| SMG Motorsport Limited | Wholesale & retail | 2023 |
| SMH Associates Limited | Professional & scientific | 2011 |
| Smith Ecology Limited | Professional & scientific | 2002 |
| Smith Software Services Limited | Information & communication | 2015 |
| Smoke 'N' Slaw Ltd | Hospitality | 2021 |
| SN Civils Ltd | Construction | 2018 |
| Snug & HUG Ltd | Hospitality | 2018 |
| SOC and COS Limited | Wholesale & retail | 2021 |
| Soldzone Limited | Wholesale & retail | 1998 |
| Somerton Films Ltd. | Information & communication | 2014 |
| Sophie Harris Limited | Information & communication | 2008 |
| South Wales Highways Limited | Construction | 2005 |
| Spartan Heating & Plumbing Services Ltd | Construction | 2021 |
| Special Educational Needs Safety Equipment Ltd | Wholesale & retail | 2026 |
| Speech Marks ( Independent Speech & Language Therapy ) Ltd | Extraterritorial | 2024 |
| Spinning Rock Ltd | Wholesale & retail | 2020 |
| Spotpull Limited | Households | 1990 |
| SRP Care Support Agency Ltd | Health & social care | 2022 |
| SRP Cleaning Group Ltd | Administrative & support | 2021 |
| SRP Group Limited | Financial services | 2022 |
| SRP Holdings Management Ltd | Financial services | 2023 |
| SRP Support Services Limited | Health & social care | 2021 |
| ST Helens Domiciliary Care Limited | Health & social care | 2013 |
| ST Mellons Business Park Limited | Real estate | 1999 |
| Stables Photography Studios Limited | Professional & scientific | 2014 |
| Star Deals Direct Limited | Wholesale & retail | 2024 |
| Stelljess Limited | Financial services | 2015 |
| Step Lane Consulting Group Ltd | Administrative & support | 2020 |
| Steven Harris Limited | Professional & scientific | 2011 |
| Steven James Consulting Ltd | Wholesale & retail | 2025 |
| Stonerise Limited | Professional & scientific | 2023 |
| Strategic Developments (International) Limited | Professional & scientific | 2019 |
| Structural Inspection Services Limited | Professional & scientific | 2015 |
| Stuart Aviation Services Ltd | Transport & logistics | 2025 |
| Studio Popty Limited | Information & communication | 2025 |
| Sturdy Fluid Power Limited | Wholesale & retail | 2009 |
| Sublime Design & Build Limited | Professional & scientific | 2023 |
| Successful BID Writing Ltd | Professional & scientific | 2015 |
| Sue's Salon Ltd | Other services | 2013 |
| Sugar Loaf Alpacas Ltd | Agriculture & fishing | 2019 |
| Sugar Loaf Events Ltd | Hospitality | 2015 |
| Sugar Loaf Lamb Ltd | Wholesale & retail | 2024 |
| Sugar Loaf Regeneration Farm Partnership CIC | Other services | 2025 |
| Sugar Lump Properties Ltd | Real estate | 2013 |
| Sugarloaf Cards Ltd | Manufacturing | 2024 |
| Sugarloaf Dairy Ltd | Hospitality | 2018 |
| Sugarloaf Property Management Ltd | Real estate | 2022 |
| Sumsam Limited | Hospitality | 2017 |
| Sundarbon Kitchen Ltd | Hospitality | 2016 |
| Sunstream Research and Consulting Limited | Professional & scientific | 2024 |
| Super Useful Ltd | Information & communication | 2018 |
| Supersips (South-West) Ltd | Manufacturing | 2017 |
| Surehomes Limited | Real estate | 2004 |
| Suyog & Sahas Ltd | Real estate | 2026 |
| Suyog Sasha Ltd | Hospitality | 2023 |
| Suzanne Haynes Fitness Ltd | Arts & recreation | 2023 |
| Suzyrooms Ltd | Real estate | 2025 |
| Swansford Solutions Limited | Professional & scientific | 1995 |
| Sweet Liberation Ltd | Information & communication | 2024 |
| Synergise ME Ltd | Education | 2016 |
| Synergy ICT Integrated Services Ltd | Information & communication | 2020 |
| Synesis Solutions Ltd | Professional & scientific | 2024 |
| Syrus Property Solutions Ltd | Real estate | 2024 |
| T B Ponty Ltd | Real estate | 2020 |
| T Young Property Ltd | Real estate | 2024 |
| T&K Jones Holdings Ltd | Real estate | 2023 |
| T-Bar-Apparel Ltd | Manufacturing | 2020 |
| T.B.S (South Wales) Holdings Limited | Manufacturing | 2005 |
| T.B.S. (South Wales) Properties Limited | Real estate | 1979 |
| TA Jones Holdings Ltd | Real estate | 2024 |
| Tabcell Limited | Financial services | 2011 |
| Taldra Limited | Construction | 2015 |
| Tapas Twist Limited | Hospitality | 2018 |
| Tapio Search Limited | Administrative & support | 2020 |
| Tarw Homes Limited | Real estate | 2016 |
| TAS Kebab Ltd | Hospitality | 2026 |
| TD Hillman Property Ltd | Real estate | 2023 |
| TED Williams & Sons Limited | Other services | 2013 |
| Tellus Financial Planning Ltd | Financial services | 2018 |
| Tenant Ready Ltd | Real estate | 2022 |
| Tenbee Property Limited | Real estate | 2024 |
| Thames Industrial Ltd | Wholesale & retail | 2024 |
| Tharssun Limited | Real estate | 1993 |
| THE 44 Main Road Gilwern Management Company Limited | Households | 2005 |
| THE Abergavenny Little Kitchen Ltd | Hospitality | 2025 |
| THE Art Shop Abergavenny Limited | Wholesale & retail | 2011 |
| THE Bell Hotel & Restaurant Ltd. | Hospitality | 2011 |
| THE Blorenge Consultancy Limited | Professional & scientific | 2014 |
| THE Brand Ambassador Academy Ltd | Education | 2026 |
| THE Bridge Llanfoist Ltd | Hospitality | 2023 |
| THE Bryn Trading Post Community Interest Company | Wholesale & retail | 2006 |
| THE Cannibal Surf Shack Limited | Information & communication | 1998 |