| Brynafon Consulting Ltd | Information & communication | 2014 |
| Brynstore Limited | Real estate | 2012 |
| BS Renewables Ltd | Construction | 2023 |
| BT Parry Brickwork Limited | Construction | 2019 |
| Build Tight Testing Ltd | Professional & scientific | 2023 |
| Building Emea Channels Limited | Information & communication | 2017 |
| Built Smart Ltd | Construction | 2024 |
| Bull Lettings Ltd | Real estate | 2024 |
| Buns & Crusts Co Ltd | Hospitality | 2025 |
| Bunting Knights Ltd | Wholesale & retail | 2025 |
| Busy Bees Blaenavon Day Nursery and Kids Club | Education | 2008 |
| Butler Wall Blaenavon Limited | Construction | 2013 |
| Butlerwall Tenby Limited | Construction | 2015 |
| Bystrata Ltd | Information & communication | 2026 |
| C West & Sons Ltd | Construction | 2025 |
| C&J W Services Ltd | Information & communication | 2022 |
| C.M.Pattison Engineers Limited | Wholesale & retail | 1967 |
| Cadland Plates Ltd | Wholesale & retail | 2025 |
| Cairns Duvar Ltd | Wholesale & retail | 2025 |
| CAL38 CIC | Education | 2026 |
| Caldwell Crest Ltd | Wholesale & retail | 2025 |
| Calon Fawr Care and Support Services Limited | Health & social care | 2022 |
| Calon LAN Support Limited | Health & social care | 2021 |
| Calvert Cross Ltd | Wholesale & retail | 2025 |
| Camborne Sands Ltd | Wholesale & retail | 2025 |
| Camlas Cars Limited | Wholesale & retail | 2025 |
| Camlas Consultancy Ltd | Information & communication | 2020 |
| Canalside Caravan Park Limited | Hospitality | 2023 |
| Candleston Limited | Construction | 2013 |
| Captain Jones Limited | Construction | 2021 |
| Card Quest Collectibles Ltd | Wholesale & retail | 2025 |
| Cardiff Consulting Group Limited | Information & communication | 2016 |
| Care & Repair Monmouthshire & Torfaen Limited | Health & social care | 2022 |
| Cariad Domiciliary Support Services Ltd | Health & social care | 2001 |
| Cariad Prints Ltd | Wholesale & retail | 2019 |
| Carlton Caster Ltd | Wholesale & retail | 2025 |
| Castle Hotel Limited | Hospitality | 2016 |
| Cat & Crow CIC | Education | 2026 |
| Catrin Cleaning Company Ltd | Administrative & support | 2025 |
| Cavell Yard Ltd | Wholesale & retail | 2025 |
| CC4 Limited | Households | 2024 |
| Cefn Gwlad Designs Limited | Construction | 2024 |
| Cefn Llan Open Space Limited | Households | 2026 |
| Celtic Joinery Limited | Construction | 2023 |
| Central Academy of Performing Arts Ltd | Arts & recreation | 2022 |
| Cerissmile CYF | Wholesale & retail | 2025 |
| Ceryllium Ltd | Professional & scientific | 2024 |
| Cgmd Ltd | Administrative & support | 2011 |
| Challender Brent Ltd | Wholesale & retail | 2025 |
| Challenger Waste Management Ltd | Water & waste | 2024 |
| Charlie's Penygarn Ltd | Hospitality | 2018 |
| Charlotte Express Packaging Limited | Manufacturing | 2015 |
| Charlotte Packaging Limited | Manufacturing | 2000 |
| Charlton Robin Ltd | Wholesale & retail | 2025 |
| Cheetah RAM Ltd | Public administration | 2022 |
| Cheston Clover Ltd | Wholesale & retail | 2025 |
| Chocoholic Heaven Ltd | Wholesale & retail | 2010 |
| Chrishell Lettings Limited | Real estate | 2025 |
| Chrystal Queer Ltd | Administrative & support | 2025 |
| Churchward Properties Limited | Real estate | 2003 |
| Circular Commodities UK Ltd | Water & waste | 2019 |
| CL2 Systems Ltd | Professional & scientific | 2011 |
| Clarence Valeting Centre Ltd | Administrative & support | 2026 |
| Clarendon Cecil Ltd | Wholesale & retail | 2025 |
| Classic Mini Adventure Limited | Wholesale & retail | 2025 |
| Cleartone Telecoms Limited | Wholesale & retail | 1976 |
| Clifans Limited | Manufacturing | 1951 |
| Clifton Arms Ltd | Wholesale & retail | 2025 |
| Clutch Master & SON Ltd | Wholesale & retail | 2025 |
| Cmbf Products (U.K.) Limited | Manufacturing | 2005 |
| Cobourg York Ltd | Wholesale & retail | 2025 |
| Codi Lee’S Ltd | Wholesale & retail | 2025 |
| Cold Heat Limited | Construction | 2018 |
| Colin Campbell Consulting Limited | Professional & scientific | 2007 |
| Collectorparcels Ltd | Wholesale & retail | 2021 |
| Collier Haulage (South Wales) Limited | Transport & logistics | 2009 |
| Colman Twelve Ltd | Wholesale & retail | 2025 |
| Cometsecuritygroup Ltd | Administrative & support | 2021 |
| Complete Broker Solutions Limited | Information & communication | 2017 |
| Complete Clean Solutions Ltd | Administrative & support | 2013 |
| Compon Ltd | Arts & recreation | 2023 |
| Concrete Antibrasive Refractory Liningsi Ltd | Construction | 2023 |
| Connections by B Ltd | Arts & recreation | 2025 |
| Construction Metal Forming Limited | Manufacturing | 2005 |
| Contactsability Limited | Health & social care | 2013 |
| Cooper Conway Pharms Ltd | Agriculture & fishing | 2025 |
| Copestick Drinks Co. Limited | Administrative & support | 2026 |
| Coreplex Limited | Information & communication | 2005 |
| Cornwall Logan Ltd | Wholesale & retail | 2025 |
| Corrin Beech Ltd | Wholesale & retail | 2024 |
| County Bathrooms & Heating Ltd | Construction | 2015 |
| County Construction Solutions Ltd | Construction | 2023 |
| Countychildcare Croesyceiliog CYF. | Health & social care | 2019 |
| Countychildcare Glan Llyn CYF | Health & social care | 2019 |
| Countychildcare Greenmeadow CYF. | Health & social care | 2019 |
| Countychildcare Llanyrafon CYF. | Health & social care | 2019 |
| Countychildcare Padrepio CYF. | Health & social care | 2019 |
| Countychildcare Ponthir Ltd | Health & social care | 2020 |
| Countychildcare Stdavidsrc CYF. | Health & social care | 2023 |
| Court Close Residents Management Company Limited | Administrative & support | 2017 |