| CDL Group Properties Ltd | Real estate | 2024 |
| Cefn Coch Sewerage Treatment Plant Management Company Limited | Extraterritorial | 2012 |
| Cefnbarrach Farms Limited | Hospitality | 2021 |
| Celtic Training UK Ltd | Information & communication | 2022 |
| Chad Fellows Homes Limited | Real estate | 2022 |
| Chaos + Order Ltd | Arts & recreation | 2023 |
| Charford Group Limited | Administrative & support | 2015 |
| Charles Humphreys Ltd | Wholesale & retail | 2019 |
| Chemical Laboratories Ltd. | Wholesale & retail | 1993 |
| Chivers&Rogers Ltd | Real estate | 2026 |
| Circular Economy MID Wales Limited | Education | 2019 |
| Claire Austin Hardy Plants Limited | Agriculture & fishing | 1999 |
| CLE Contractors Ltd | Construction | 2021 |
| CLF Groundworks Limited | Construction | 2020 |
| Climate Action Newtown CIC | Other services | 2021 |
| Close Protection World Limited | Administrative & support | 2012 |
| Clough Williams-Ellis Nominee Company Limited | Financial services | 2016 |
| Colin Foulkes Tyres Limited | Wholesale & retail | 2019 |
| Common Cause Foundation | Education | 2015 |
| Compass Community Care Limited | Health & social care | 2000 |
| Compass Investment Property Ltd | Real estate | 2025 |
| Complete Move Limited | Information & communication | 2022 |
| Concord Hydraulics Limited | Professional & scientific | 1984 |
| Confederate Chemicals GRP Limited | Manufacturing | 2014 |
| Consilium Systems Limited | Information & communication | 2025 |
| Constructiv Clothing Limited | Manufacturing | 2010 |
| Contender Studios Ltd | Information & communication | 2016 |
| Copperhouse Films Ltd | Information & communication | 2023 |
| Corinthian Paradiso Consulting Ltd | Administrative & support | 2024 |
| Cornerstone Advisory Group Limited | Professional & scientific | 2026 |
| Costel Nedelcu Ltd | Transport & logistics | 2025 |
| Costume Studio Limited | Arts & recreation | 1987 |
| Cosy Night Limited | Hospitality | 2025 |
| CPL UK Investments Ltd | Financial services | 2025 |
| Craven Arms Hand Car Wash Ltd | Administrative & support | 2023 |
| CRD Construction Limited | Construction | 2013 |
| CRE8 Wellbeing Ltd | Health & social care | 2022 |
| Creative Stuff Newtown Community Interest Company | Arts & recreation | 2021 |
| Cricket Matters Ltd | Arts & recreation | 2022 |
| Crop Surveillance Limited | Administrative & support | 2011 |
| Crugnant Farm Ltd | Agriculture & fishing | 2026 |
| Cupiditas Ltd | Administrative & support | 2014 |
| Custom Fasteners Limited | Wholesale & retail | 2015 |
| Cwtchy Campers Limited | Manufacturing | 2023 |
| D and S Richards Properties Ltd | Real estate | 2025 |
| D Marshall Ltd | Professional & scientific | 2020 |
| D.R.E. Holdings Ltd | Manufacturing | 2007 |
| D88 Properties Limited | Real estate | 2025 |
| Dagga Ltd | Wholesale & retail | 2012 |
| Dale Warren & SON Ltd | Construction | 2011 |
| DAM Holdings and Investments Ltd | Financial services | 2025 |
| Darwin Property Solutions Limited | Construction | 2026 |
| Dave Williams Construction and Plant Hire Limited | Construction | 2022 |
| Davies Enterprise Holdings Limited | Financial services | 2021 |
| Daxaid Limited | Manufacturing | 2020 |
| DC Autos (Newtown) Limited | Wholesale & retail | 2010 |
| Ddolfadog Farms Limited | Professional & scientific | 2016 |
| DE Bens Industries Limited | | 1984 |
| Deal Tree K Limited | Administrative & support | 2024 |
| Derwas Holdings Limited | Financial services | 2014 |
| Derwent Power Limited | Energy | 2014 |
| Derwent Renewable Power Limited | Energy | 2015 |
| DGM Construction Limited | Construction | 2003 |
| Direct Control Systems Limited | Construction | 1993 |
| DMR Property Ventures Ltd | Real estate | 2026 |
| Dolywind Ltd | Energy | 2025 |
| Donlo Janitorial Ltd | Wholesale & retail | 2024 |
| Donna Griffiths Limited | Health & social care | 2014 |
| Douglas Hughes Architects Limited | Professional & scientific | 2003 |
| DR RR Limited | Health & social care | 2021 |
| Dragon Joinery Ltd | Manufacturing | 2003 |
| Dragon's Lair Newtown Limited | Hospitality | 2013 |
| Drivesshop Limited | Extraterritorial | 1999 |
| DS Analytics and Machine Learning Ltd | Information & communication | 2016 |
| Duma Technical Services Limited | Wholesale & retail | 1989 |
| Duti Ltd | Real estate | 2022 |
| DYFFRYN6 Ltd | Manufacturing | 2016 |
| DYFFRYN6BG Limited | Financial services | 2023 |
| Dyke Engineering Ltd | Manufacturing | 2005 |
| E. Morrish Ltd | Manufacturing | 2020 |
| E.O.M.(Electrical Contractors)Ltd | Construction | 1994 |
| EBC Grab & Haulage Ltd | Water & waste | 2025 |
| EBC Groundworks Ltd | Construction | 2023 |
| Ecomet Shop Ltd | Wholesale & retail | 2024 |
| Eddie Maguire Plumbing and Heating Limited | Construction | 2016 |
| Edward Jones Contractors Limited | Agriculture & fishing | 2017 |
| Electric Classic Cars Holdings Ltd | Financial services | 2023 |
| Electric Classic Cars Limited | Manufacturing | 2016 |
| Elephant & Castle Hotel Limited | Hospitality | 2009 |
| Elite Auto Recruitment Ltd | Professional & scientific | 2025 |
| Ellen Calvert Limited | Wholesale & retail | 2012 |
| Elmo Specialists Ltd | Health & social care | 2021 |
| Elnac Ltd | Information & communication | 2020 |
| Emma Capener Art Limited | Arts & recreation | 2022 |
| Empire Martial Arts Limited | Arts & recreation | 2019 |
| Energized Electrical Contractors Ltd | Construction | 2008 |
| Erco Cafe and Restaurant Ltd | Hospitality | 2024 |
| Escalade Services PVT Limited | Information & communication | 2014 |
| Esh.Ep. Management Ltd | Agriculture & fishing | 2020 |
| ET Bookkeeping Services Ltd | Professional & scientific | 2016 |