| Compost AID Train Ltd | Education | 2013 |
| Comprador Communications Limited | Information & communication | 1992 |
| Compressor Systems (Wales) Limited | Administrative & support | 2008 |
| Concept and Project Engineering Ltd | Manufacturing | 2019 |
| Congress Theatre Company | Arts & recreation | 2009 |
| Connect Your Social Ltd | Information & communication | 2015 |
| Consilium Consulting Engineers Limited | Professional & scientific | 2019 |
| Consilium Solutions Group LLP | | 2018 |
| Consulteq Ltd | Professional & scientific | 2012 |
| Continuum Intelligence Limited | Information & communication | 2026 |
| Control Systems Services Ltd. | Manufacturing | 1993 |
| Convene X Events Ltd | Professional & scientific | 2025 |
| Convert Leads Ltd | Information & communication | 2024 |
| Conway Developers Ltd | Construction | 2024 |
| Cookieonline Limited | Information & communication | 2017 |
| Coombe Farms Limited | Agriculture & fishing | 2011 |
| Corimark Property Investments Ltd | Real estate | 2022 |
| Cornerbit Ltd | Information & communication | 2025 |
| Cornfinch Management Services Limited | Construction | 2002 |
| Cosmetic Vehicle Repairs Limited | Wholesale & retail | 2006 |
| Costar Partnership | Hospitality | 2003 |
| County Roofing Ltd | Construction | 2025 |
| County Scaffolding Services (CSS) Ltd | Construction | 2020 |
| Cova Delivery Ltd | Transport & logistics | 2019 |
| Covid Bereaved Families for Justice Cymru Ltd | Information & communication | 2026 |
| Cozee Cats & Equestrian Centre Ltd. | Agriculture & fishing | 2007 |
| Craig Hawkins and SON Accident Repair Centre Ltd | Wholesale & retail | 2026 |
| Crazy Loyalty Limited | Information & communication | 2021 |
| CRE8IVE Products Limited | Manufacturing | 2015 |
| Crescent Cleaning Solutions Ltd | Administrative & support | 2026 |
| Croesyceiliog Rugby Football Club Limited | Arts & recreation | 2022 |
| Crossford OIL & Tool Supplies Ltd | Wholesale & retail | 1981 |
| Crow Valley GAS Services and Electrical Installation Ltd | Construction | 2012 |
| Crow Valley Motor Company Ltd | Wholesale & retail | 2022 |
| Crow Valley Performance Ltd | Wholesale & retail | 2025 |
| Crow Valley Property Services Ltd | Households | 2025 |
| Crow Valley Services Limited | Professional & scientific | 2008 |
| Crownhill Monmouthshire Limited | Construction | 2025 |
| Crystal Luxury Events Ltd | Extraterritorial | 2020 |
| CSW Controls Limited | Extraterritorial | 2013 |
| CSW Mortgages Limited | Financial services | 2020 |
| CTK Enterprises Limited | Administrative & support | 2003 |
| Ctrl ALT Elite Studio Ltd | Information & communication | 2026 |
| Cupcakes 'N' Dinosaurs, New Inn Limited | Education | 2015 |
| Curry & Collier Ltd | Real estate | 2020 |
| Curry Kitchen 44 Ltd | Hospitality | 2023 |
| Curtis Automotive Ltd | Wholesale & retail | 2025 |
| Custom Design Mouldings Limited | Manufacturing | 1976 |
| Customise R US Ltd | Manufacturing | 2020 |
| CW Mould Solutions Ltd | Construction | 2025 |
| CWM Fresh Ltd | Administrative & support | 2018 |
| Cwmbran Angling Association | Arts & recreation | 2011 |
| Cwmbran Beauty Ltd | Other services | 2025 |
| Cwmbran Car Breakers Limited | Other services | 2024 |
| Cwmbran Centre for Young People | Information & communication | 2004 |
| Cwmbran Commercial Repairs Ltd | Wholesale & retail | 2024 |
| Cwmbran Dental Care Limited | Health & social care | 2010 |
| Cwmbran Door Centre Ltd | Manufacturing | 2011 |
| Cwmbran Electrical Services Limited | Manufacturing | 1964 |
| Cwmbran Fire Protection (SW) Limited | Administrative & support | 2005 |
| Cwmbran Golden Style Limited | Other services | 2020 |
| Cwmbran Hand Car Wash Ltd | Wholesale & retail | 2020 |
| Cwmbran Kitchen Floors and Doors Limited | Construction | 2024 |
| Cwmbran Motors Ltd | Wholesale & retail | 2025 |
| Cwmbran Self Storage Ltd | Transport & logistics | 2021 |
| Cwmbran Skin Clinic Limited | Health & social care | 2017 |
| Cwmbran Tandoori Limited | Hospitality | 2019 |
| Cwmbran Timber & DIY Supplies Limited | Wholesale & retail | 2000 |
| Cwmbran Tuning & Service Centre Ltd | Wholesale & retail | 2023 |
| Cwmbran Tyres Limited | Wholesale & retail | 2014 |
| Cwmbrangarages Ltd | Wholesale & retail | 2019 |
| Cwmni ORT Limited | Real estate | 2016 |
| Cwmsork Ltd | Hospitality | 2024 |
| Cwmyoy Holdings Unlimited | Financial services | 2017 |
| Cwrt Bar Ltd | Hospitality | 2026 |
| Cwrt Maerdy Properties Limited | Real estate | 2024 |
| Cwtch Homes Limited | Real estate | 2014 |
| Cymru Glass & Glazing Limited | Construction | 2007 |
| D & M Landscaping Limited | Administrative & support | 2005 |
| D a Styles Ltd | Hospitality | 2018 |
| D B Specialist Cars Ltd | Wholesale & retail | 2025 |
| D E Building Contractors Limited | Construction | 2024 |
| D J Decorators Ltd. | Construction | 2002 |
| D J Poultry Limited | Agriculture & fishing | 2009 |
| D M O’Brien Construction Ltd | Construction | 2021 |
| D Miller Property Ltd | Real estate | 2024 |
| D Moore Windows & Plastics Limited | Wholesale & retail | 2014 |
| D R Draughting Ltd | Professional & scientific | 2021 |
| D T Contracting (South West) Limited | Construction | 2013 |
| D&Sg Sausage Ltd | Manufacturing | 2017 |
| D. W Roper (Electrical Contractor) Ltd | Construction | 2011 |
| D.H. & S.J. Preece Limited | Construction | 1973 |
| D.K. Forecourts Limited | Wholesale & retail | 1995 |
| D.K.Commercial Property Limited | Financial services | 2018 |
| D.K.P. Mechanical Services Limited | Manufacturing | 2015 |
| D.R Electrical Services Ltd | Construction | 2020 |
| D.S Utilities Ltd | Construction | 2026 |
| D.T. Rosser Properties Ltd | Real estate | 1990 |
| DAB Electrics Limited | Construction | 2018 |
| DAE Caravan Services Ltd | Manufacturing | 2017 |