| Astrand Motors Ltd | Wholesale & retail | 1994 |
| Astrum Books Limited | Information & communication | 2022 |
| ATV Bikes Ltd | Wholesale & retail | 2014 |
| ATW Private Limited | Information & communication | 2025 |
| Authentic World Foods Limited | Manufacturing | 2015 |
| Auto-Matt-Ic Ltd | Wholesale & retail | 2024 |
| AVB (Aber) Limited | Wholesale & retail | 2024 |
| AW Mears Consultancy Ltd | Professional & scientific | 2020 |
| AYP Consulting (UK) Ltd | Health & social care | 2021 |
| B&H Leach Limited | Extraterritorial | 2024 |
| B.F Global Services Ltd | Wholesale & retail | 2015 |
| Back 2 Front Physiotherapy Ltd | Health & social care | 2015 |
| Bannau Learning Collective Limited | Information & communication | 2025 |
| Barglo Rentals Ltd | Households | 2023 |
| BB Sparks Limited | Construction | 2018 |
| BE Yoga Love Ltd | Health & social care | 2024 |
| Bean Bros Ltd | Hospitality | 2026 |
| Bedrooms, Kitchens and Bathrooms Limited | Construction | 2015 |
| Bemrig Group Limited | Construction | 2022 |
| Bertram Dudley & Co Ltd | Manufacturing | 2018 |
| Best Works Limited | Real estate | 2012 |
| BHL FIX Ltd | Construction | 2026 |
| Billa's Food Ltd | Hospitality | 2019 |
| Black Gold Event Rigging Ltd | Arts & recreation | 2026 |
| Black Horse SW Properties Ltd | Real estate | 2026 |
| Blore Edwards Limited | Manufacturing | 2014 |
| Blue Light Service Group Limited | Administrative & support | 2026 |
| Blue Light Services Group Ltd | Administrative & support | 2021 |
| Bluebox Removals & Transport Ltd | Transport & logistics | 2025 |
| Bluemotors Aberdare Ltd | Wholesale & retail | 2025 |
| Bonanza Leisure Limited | Wholesale & retail | 2009 |
| Bonanza Trading Limited | Financial services | 2009 |
| Bonnie Rott Limited | Professional & scientific | 2025 |
| BPI Consultancy Limited | Professional & scientific | 2000 |
| Bradevansdelivers Limited | Transport & logistics | 2025 |
| Bream Housing Ltd | Construction | 2026 |
| Breath of Fresh Care Ltd | Health & social care | 2025 |
| Brennan Architectural Design Ltd | Professional & scientific | 2023 |
| Brennan Design & Developments Ltd | Construction | 2023 |
| Bright Heart Training Ltd | Education | 2018 |
| Brimor Environmental Services Ltd | Water & waste | 2025 |
| Bristol Building Contracts Ltd | Construction | 2015 |
| Brite Light Letting Limited | Real estate | 2011 |
| Britsync Global Ltd | Professional & scientific | 2025 |
| Brooks Rail Ltd | Construction | 2014 |
| Bugzone Ltd | Wholesale & retail | 2022 |
| Building Neads Limited | Construction | 2005 |
| Burner Efficiency Services Limited | Construction | 2006 |
| Bush Healthcare ( Showers ) Limited | Construction | 2023 |
| Bush Healthcare (Stairlifts ) Limited | Manufacturing | 2024 |
| Busy Pins and Needles Ltd | Wholesale & retail | 2022 |
| Bute Chambers Limited | Real estate | 1982 |
| C & C Wood Ltd | Construction | 2021 |
| C Hergest Ltd | Professional & scientific | 2014 |
| C&N Van & Commercials Ltd | Wholesale & retail | 2019 |
| C'N'C Home Improvements Limited | Construction | 2015 |
| C.I.T Land and Property Developers Ltd | Construction | 2012 |
| C.I.T. Holdings Ltd | Real estate | 2023 |
| C.P. Property Limited | Real estate | 1996 |
| Cadre Consultants UK Limited | Administrative & support | 2010 |
| Callan Farrell Consultants Limited | Professional & scientific | 2025 |
| CAP Properties (South Wales) Limited | Real estate | 2004 |
| Capricorn Windows Ltd | Construction | 2003 |
| Cardiff Road Fish Bar Limited | Hospitality | 2005 |
| Care Credentials Wales Ltd | Education | 2013 |
| Carililiseb Holdings Ltd | Financial services | 2022 |
| Carl Sweet Ltd | Construction | 2009 |
| Carpet Fit (Wales) Ltd | Wholesale & retail | 2010 |
| Carrera Cars (Wales) Ltd | Wholesale & retail | 2013 |
| Carrington-Wolf Advocacy Ltd | Professional & scientific | 2025 |
| Carter Llewellyn Recruitment Ltd | Administrative & support | 2016 |
| Cartref Perffaith Investments Limited | Real estate | 2026 |
| Case Cafe Ltd | Hospitality | 2022 |
| Castle Care Specialist Services Limited | Health & social care | 2008 |
| Castle Care Supported Living Ltd | Health & social care | 2009 |
| Caviell Property Investments Ltd | Households | 2025 |
| CB Property SW Ltd | Real estate | 2026 |
| Cbmg Electrical Services Ltd | Construction | 2026 |
| CCS (Aberdare) Ltd | Administrative & support | 2019 |
| CDC Developers Ltd | Construction | 2024 |
| Cdej Ltd | Health & social care | 2022 |
| Celtic Damproofing Limited | Construction | 2001 |
| Celtic Valley Consulting Limited | Professional & scientific | 2022 |
| Cenarth Developments Ltd | Construction | 2021 |
| Centavia Health Limited | Wholesale & retail | 2025 |
| Central Fish Bar (Aberdare) Limited | Hospitality | 2004 |
| Centre Point Surveys Limited | Professional & scientific | 2001 |
| CF44 Performance Limited | Hospitality | 2024 |
| Chameleon Interior Design Limited | Wholesale & retail | 2006 |
| Cheffin Properties Ltd | Real estate | 2007 |
| CHG Properties Ltd | Real estate | 2020 |
| Chikgee Ltd | Health & social care | 2025 |
| Chris Davies Funeral Services Ltd | Other services | 2018 |
| Chris Evans Building Contractors Limited | Construction | 2011 |
| Christoph Hillebrand Limited | Manufacturing | 2025 |
| Ciur (UK) Limited | Water & waste | 2011 |
| CJC Estates Ltd | Construction | 2012 |
| CJC Plant Hire Ltd | Construction | 2026 |
| Ckmd Ltd | Hospitality | 2023 |
| CLAD9 Ltd | Construction | 2023 |