| THE Dotted Crotchet Limited | Arts & recreation | 2021 |
| THE Dream Projects Ltd | Real estate | 2020 |
| THE Falcon Retreat Ltd | Real estate | 2022 |
| THE Gingerbread House (RCT) Ltd | Health & social care | 2016 |
| THE Martin Bush Group Limited | Manufacturing | 2022 |
| THE Old Town Hall (Aberdare) Ltd. | Wholesale & retail | 2007 |
| THE Penderyn Furniture Co. Ltd | Wholesale & retail | 2015 |
| THE Rendering Hub Ltd | Construction | 2021 |
| THE Steri-Brush People Limited | Health & social care | 2017 |
| THE Taff Collective Limited | Wholesale & retail | 2025 |
| THE TON (Cwmdare) Ltd | Hospitality | 2023 |
| THE TON Inn Ltd | Hospitality | 2025 |
| THE Tonglwydfawr Inn Ltd | Hospitality | 2018 |
| THE Town Hall (Aberdare) Limited | Hospitality | 2009 |
| THE Tramway Management Company Limited | Households | 2005 |
| THE TY Glyn Davis Trust Limited | Health & social care | 1996 |
| THE Vapour DEN Ltd | Wholesale & retail | 2013 |
| THE Wedding Guys Ltd | Professional & scientific | 2024 |
| Thomas & Rose Property Management Ltd | Real estate | 2009 |
| Thorus Building Services Ltd | Construction | 2025 |
| Thoughtful Response Ltd | Information & communication | 2008 |
| Threecine Ltd | Information & communication | 2023 |
| Tile and Stone South Wales Limited | Construction | 2023 |
| TIN HAY Garden Ltd. | Hospitality | 2016 |
| TIP Top Toilets Holdings Limited | Financial services | 2018 |
| TIP Top Toilets Limited | Administrative & support | 2010 |
| TIP Waste Ltd | Water & waste | 2025 |
| TJ Build Ltd | Construction | 2023 |
| TJ Surveying Services Ltd | Professional & scientific | 2017 |
| TJC Surveying Services Ltd | Professional & scientific | 2018 |
| TJH Rail and Construction Limited | Construction | 2019 |
| TJM Direct Ltd | Wholesale & retail | 2023 |
| TMZ Electrical Limited | Construction | 2017 |
| TOM Hope Contractors Limited | Construction | 2024 |
| Tony Webb Transport Consultancy Ltd | Extraterritorial | 2024 |
| Topspec Motors Limited | Wholesale & retail | 2014 |
| Totalise Trading Limited | Wholesale & retail | 2025 |
| Tower Colliery Limited | Mining & quarrying | 1994 |
| Tower Energy Resources Limited | Administrative & support | 1997 |
| TP Hearing Limited | Wholesale & retail | 2021 |
| Traditional Fish & Chips @ 65 Ltd | Hospitality | 2025 |
| Training and Funding Solutions Ltd | Education | 2019 |
| Trauma Informed Solutions Ltd | Professional & scientific | 2016 |
| Trentward Limited | Arts & recreation | 1991 |
| Trewen Consulting Ltd | Professional & scientific | 2024 |
| Trident Motor Spares Limited | Wholesale & retail | 2014 |
| Trident Tyre & Accessories Limited | Wholesale & retail | 1969 |
| Tripillar Group Limited | Real estate | 2026 |
| TTR - Trems Transport Recovery Ltd | Transport & logistics | 2022 |
| Tunnel Cottages Ltd | Hospitality | 2025 |
| Turner Davies Electrical & Property Services Ltd | Construction | 2010 |
| Turner Davies Holdings Limited | Financial services | 2020 |
| Twindraig Limited | Arts & recreation | 2022 |
| Two Brews Coffee & Brunch Ltd | Hospitality | 2025 |
| TY Brawd Ltd | Real estate | 2024 |
| TY Diwydiannol Ltd | Real estate | 2026 |
| TY Newydd Trading Company Ltd | Agriculture & fishing | 2006 |
| Tycon Developments Limited | Construction | 2016 |
| Tyre Recycling Services (Wales) Ltd | Water & waste | 2024 |
| Tyrone Probert Rail Ltd | Construction | 2018 |
| Ucan Care Limited | Health & social care | 2005 |
| Ultrastone Limited | Manufacturing | 2022 |
| Unit Base Catering B Ltd | Hospitality | 2023 |
| Units Direct Ltd | Real estate | 2024 |
| Untamable Fightwear Ltd | Manufacturing | 2024 |
| Upvc & Roofing Ltd | Administrative & support | 2017 |
| Urnurs UK Ltd | Health & social care | 2025 |
| V G Jarvis Coaches Limited | Transport & logistics | 2016 |
| Vale Autotec Limited | Wholesale & retail | 2008 |
| Valley Cleaning Solutions Ltd | Administrative & support | 2020 |
| Valley Logistics Ltd | Transport & logistics | 2026 |
| Valley's Homes Limited | Real estate | 2008 |
| Valley's Maintenance Limited | Construction | 2023 |
| Valleys VEG Ltd | Agriculture & fishing | 2021 |
| Vanquish Motor Spares Ltd | Wholesale & retail | 2018 |
| Velrox Fuel Technology Ltd | Wholesale & retail | 2026 |
| Veridion Consultancy Limited | Professional & scientific | 2014 |
| Veritas Financial Planning Limited | Financial services | 2015 |
| VHL Brickwork Ltd | Construction | 2026 |
| Victoria Bond Consulting Ltd | Professional & scientific | 2017 |
| Victory Home Sense Limited | Real estate | 2024 |
| Visage a LA Mode Ltd | Other services | 2024 |
| Vision Build Solutions Ltd | Construction | 2025 |
| Visionbuild Services Ltd | Construction | 2025 |
| Vital Care Housing Ltd | Real estate | 2025 |
| Vortex Environmental Services Ltd | Administrative & support | 2014 |
| W and B Homes Limited | Real estate | 2023 |
| W S Plant & Agriculture Services Ltd | Manufacturing | 2023 |
| WAD Electrical Ltd | Manufacturing | 2021 |
| Wagfest Ltd | Arts & recreation | 2025 |
| Walters Land (Barry) Limited | Construction | 2013 |
| Walters Land (Rogerstone) Limited | Water & waste | 2012 |
| Walters Land Limited | Construction | 2002 |
| Walters Major Projects Limited | Construction | 2016 |
| Walters Plant Hire Limited | Construction | 1994 |
| Walters Regeneration Limited | Construction | 2003 |
| Walters Residential Limited | Real estate | 2015 |
| WBS Developments (South Wales) Limited | Financial services | 2023 |
| WDL Management Limited | Households | 2020 |
| Webbers@Sbend Limited | Hospitality | 2021 |