| 38 Stacey Road Property Management Company Limited | Households | 2004 |
| 3HMFIRE Ltd | Education | 2022 |
| 44 Dunraven Street Limited | Real estate | 2019 |
| 4D Academy Ltd | Education | 2019 |
| 556 Safety Limited | Professional & scientific | 2024 |
| A D V Accountancy Limited | Professional & scientific | 2009 |
| A Trembath Plant, Groundworks and Haulage Contractors Limited | Construction | 2015 |
| Abbotts Events Limited | Hospitality | 2019 |
| Accessio Ltd | Professional & scientific | 2024 |
| Accountants Plus Limited | Professional & scientific | 2000 |
| Aderyn Limited | Other services | 2009 |
| Advertising Productions Limited | | 1986 |
| Aero Surveying Limited | Construction | 2012 |
| Airfield & Business Consultancy Limited | Extraterritorial | 2025 |
| AJE Evans Limited | Financial services | 2021 |
| AJP Building Limited | Real estate | 2006 |
| AK & Co Properties Ltd | Wholesale & retail | 2019 |
| Alesky Limited | Wholesale & retail | 2025 |
| Alexis Healthcare Recruitment and Service Limited | Health & social care | 2022 |
| Alien-Unlimited Limited | Wholesale & retail | 2014 |
| ALL Spec Solutions Ltd | Construction | 2020 |
| Allied Living History Group CIC | Professional & scientific | 2024 |
| Almi Service Limited | Wholesale & retail | 2020 |
| ALO MOT Service Ltd | Wholesale & retail | 2023 |
| ALO Taxi Ltd | Transport & logistics | 2023 |
| Alpine Financial Services Ltd | Financial services | 2022 |
| Alty Homes Ltd | Real estate | 2024 |
| American Nails Tonypandy Ltd | Other services | 2026 |
| Andrews Petrol Services Limited | Wholesale & retail | 2015 |
| Annabelle Huntley Limited | Other services | 2024 |
| Apex Commerce Market Ltd | Wholesale & retail | 2026 |
| Apple Tree Carpentry & Construction Ltd | Manufacturing | 2021 |
| Ascend Property Services Group Ltd | Real estate | 2026 |
| Ashbee Civils UK Ltd | Construction | 2019 |
| Autism Life Centres CIC | Health & social care | 2015 |
| B Signature Aesthetics Ltd | Health & social care | 2025 |
| B-Speed Logistic Ltd | Transport & logistics | 2025 |
| Barbara Rees Ltd | Real estate | 2002 |
| Barodi Ltd | Hospitality | 2026 |
| Bassett General Services Ltd | Transport & logistics | 2023 |
| Belrocc Productions Limited | Construction | 2013 |
| Berbillion's Burger Bar Ltd | Hospitality | 2026 |
| Berbillion’S Removals Ltd | Transport & logistics | 2026 |
| Better Property Services Ltd | Administrative & support | 2024 |
| BH Adref Limited | Construction | 2021 |
| Big Dog Van Accessories Limited | Manufacturing | 2025 |
| Birchwood Mobile Office Co.Limited(The) | Administrative & support | 1972 |
| Bj's Roofing Services Ltd | Construction | 2024 |
| BKM Limited | Health & social care | 1993 |
| BNC Painting and Decorating (South Wales) Ltd | Construction | 2026 |
| Bob's Brunch Limited | Hospitality | 2017 |
| Bobba Food Fusion Limited | Hospitality | 2025 |
| BOOZE247 Limited | Wholesale & retail | 2023 |
| Bradleys Homes Ltd | Real estate | 2022 |
| Brent Thomas Coaches Limited | Transport & logistics | 2006 |
| Bricks & Fire Ltd | Construction | 2025 |
| BTM Electrical Services Ltd | Construction | 2025 |
| BTM Residential Ltd | Real estate | 2025 |
| Bucknor Renewables Construction Management Ltd | Construction | 2025 |
| Butchers Kitchen Limited | Hospitality | 2025 |
| Butchery Bocs Limited | Wholesale & retail | 2022 |
| C N Construction Svcs Ltd | Construction | 2010 |
| C45H 4 Cars Limited | Wholesale & retail | 2016 |
| Cambrian Lakeside Ltd | Arts & recreation | 2013 |
| Cambrian Trade Specialists Limited | Construction | 2021 |
| Cambrian Village Trust Limited | Education | 2018 |
| Cambrian Welfare RFC Limited | Hospitality | 2026 |
| Cameron-James Wealth Management Ltd | Professional & scientific | 2024 |
| Capel Associates Ltd | Professional & scientific | 2023 |
| Capriole Express Ltd | Wholesale & retail | 2026 |
| Carreg Consulting Ltd | Construction | 2017 |
| Carters Couriers Limited | Transport & logistics | 2025 |
| Caterpillar Business Psychologists Ltd | Professional & scientific | 2002 |
| Celtic Dragon Services Ltd | Construction | 2020 |
| CF40 Limited | Other services | 2008 |
| Chestilly Holdings Limited | Financial services | 2025 |
| Chronowin Limited | Arts & recreation | 2026 |
| CJS Signalling Ltd | Construction | 2022 |
| Claire's Community Support Services Ltd | Health & social care | 2025 |
| Clarke HSE Solutions Ltd | Professional & scientific | 2026 |
| Clwb Coffi Ltd | Hospitality | 2019 |
| CMB Business Management Limited | Wholesale & retail | 2003 |
| Coalfield Flower Farm CIC | Wholesale & retail | 2021 |
| Cobra Workwear Ltd | Manufacturing | 2022 |
| Code Knights Limited | Information & communication | 2026 |
| Coffee 11 Limited | Hospitality | 2025 |
| Colcombe Capital Group Ltd | Financial services | 2025 |
| Commercially AI (UK) Ltd | Professional & scientific | 2026 |
| Complete Commercial Contractors Ltd | Construction | 2025 |
| Cookies and Kreme Tonypandy Ltd | Hospitality | 2025 |
| Cool Girl Clubhouse Ltd | Arts & recreation | 2025 |
| Cooply Solutions Ltd | Information & communication | 2007 |
| Cpiwales Ltd | Real estate | 2022 |
| Craft of Hearts Ltd | Wholesale & retail | 2012 |
| Craftwood Furniture Ltd | Manufacturing | 2019 |
| Creatoracademi CIC | Education | 2026 |
| CS Llewellyn Haulage Ltd | Transport & logistics | 2018 |
| CS Rail Services Ltd | Transport & logistics | 2015 |
| Curtis Bowden & Thomas Limited | Professional & scientific | 2003 |
| CWM Cariad Enterprises Ltd | Manufacturing | 2019 |