| Byyoursew Ltd | Wholesale & retail | 2026 |
| C & L Concrete Ltd | Construction | 2015 |
| C Gallagher Ltd | Construction | 2018 |
| C Mcgowan Property Ltd | Real estate | 2025 |
| C&J Carsales NI Ltd | Wholesale & retail | 2019 |
| C&P Ireland Ltd | Construction | 2025 |
| C. & G. Retail Limited | Wholesale & retail | 2003 |
| C.M.F. (Strabane) Ltd | Wholesale & retail | 2011 |
| Caffe Milano Limited | Hospitality | 2019 |
| Caldwell Brothers Plant Hire Ltd | Construction | 2018 |
| Caldwell Demolition Limited | Construction | 2020 |
| Calf Barns Ltd | Agriculture & fishing | 2025 |
| Caliway Ltd | Wholesale & retail | 2018 |
| Cannon Coach and BUS Limited | Manufacturing | 2016 |
| Cannon Coach Ltd | Manufacturing | 2024 |
| Cargate Leasing Ltd | Administrative & support | 2014 |
| Carmen Consulting Services Ltd | Professional & scientific | 2024 |
| Carolina Apartments Managemet Co. Ltd | Real estate | 2008 |
| Carrick Engineering Limited | Manufacturing | 2017 |
| Carrick Systems Ltd | Wholesale & retail | 2021 |
| Carrickdon Developments Limited | Construction | 2007 |
| Carricklee Breeze Ltd | Energy | 2012 |
| CAS Construction & Concreting Ltd | Construction | 2021 |
| CAS Developments Limited | Construction | 2023 |
| Casey's Salmon Ltd | Wholesale & retail | 2008 |
| Casino Grand Limited | Arts & recreation | 2011 |
| Casino Holdings Limited | Financial services | 2016 |
| Castle Star Property Holdings Limited | Real estate | 2017 |
| Castletown Berehaven Holdings Limited | Extraterritorial | 2021 |
| Castletown Electrics Limited | Construction | 2014 |
| Castletown Renewable Energy Limited | Energy | 2013 |
| Caulfield Composites Ltd | Manufacturing | 2021 |
| Cavanalee Contracts Limited | Administrative & support | 2018 |
| CBM Contracts Ltd | Construction | 2016 |
| CC Trade Cars Ltd | Wholesale & retail | 2025 |
| CEA Formwork Limited | Construction | 2021 |
| CFC Ltd | Construction | 2025 |
| Charlie & Colin Crumley Ltd | Agriculture & fishing | 2022 |
| Charlie's Bar Ltd | Hospitality | 2013 |
| Cherrymore UK Ltd | Extraterritorial | 2012 |
| Cherryvale Decor Ltd | Construction | 2019 |
| Chill Repair | Manufacturing | 2023 |
| Chipzel Ltd | Arts & recreation | 2020 |
| Choc U LOT Ltd | Wholesale & retail | 2022 |
| Chris Mccauley Construction Ltd | Construction | 2016 |
| Christopher Boyle Consultants Ltd | Construction | 2010 |
| Christy's Bar (N.I.) Ltd | Hospitality | 2016 |
| Cita Furniture Ltd | Manufacturing | 2008 |
| City Fireplaces Ltd | Wholesale & retail | 2020 |
| CKS Catering Ltd | Hospitality | 2008 |
| Clady Fuels Ltd | Wholesale & retail | 2014 |
| Clady Hill Energy Limited | Energy | 2013 |
| Claimsassist (NI) Limited | Administrative & support | 2003 |
| Clarke Contracts and Civils Limited | Construction | 2014 |
| Class ACT Theatre Group Ltd | Arts & recreation | 2020 |
| Cleaning Network Solutions Ltd | Wholesale & retail | 2024 |
| CMC Builders Ltd | Construction | 2018 |
| CMD Construction Ltd | Construction | 2019 |
| Cock N' Bull Bar & Restaurant Ltd | Hospitality | 2015 |
| Colhoun Holdings Ltd | Financial services | 2023 |
| Commtex Ltd | Construction | 2021 |
| Complete Access Solutions INL Limited | Construction | 2024 |
| Compliance (N.I.) Ltd | Manufacturing | 2020 |
| Concal Holdings Limited | Financial services | 2025 |
| Conn Tinney Groundworks Limited | Construction | 2018 |
| Connolly Contracts Ltd | Construction | 2022 |
| Connor Joseph Doherty T/A CDS Ltd | Wholesale & retail | 2025 |
| Conor Dolan Motors Ltd | Wholesale & retail | 2020 |
| Conor Kelly Ltd | Construction | 2014 |
| Conor Logue Motors Ltd | Wholesale & retail | 2023 |
| Cool Castles Ltd | Arts & recreation | 2019 |
| Cool Running Systems Ltd | Professional & scientific | 2020 |
| Coolatee Joinery Ltd | Construction | 2010 |
| Core Power and Control Ltd | Construction | 2013 |
| Core Switchgear Limited | Manufacturing | 2023 |
| Coulter Advisory Ltd | Professional & scientific | 2025 |
| Country Kids Childcare Ltd | Health & social care | 2013 |
| Coylin Ltd | Real estate | 2022 |
| CR3 Architecture Ltd | Construction | 2018 |
| Craft Training Ltd | Arts & recreation | 2013 |
| Craig & Lindsay Building Contractors Limited | Construction | 2018 |
| Crane CAD Solutions Ltd | Professional & scientific | 2025 |
| Crazy Cabs Ltd | Transport & logistics | 2011 |
| CSP Joinery Ltd | Manufacturing | 2015 |
| Cummings Bros Plant Hire & Grounds Work Ltd | Construction | 2017 |
| Cummings Brothers Ltd | Construction | 2017 |
| Cummings Contracts Ltd | Construction | 2017 |
| Curley Hill Manor Limited | Construction | 2014 |
| Cutting Edge Training (NI) Limited | Education | 2011 |
| D & M Homes Ireland Ltd | Real estate | 2024 |
| D Black & SON Limited | Agriculture & fishing | 2014 |
| D C Tyres Ltd | Wholesale & retail | 2005 |
| D Gallen Construction Limited | Construction | 2014 |
| D Hunter Glass Ltd | Construction | 2022 |
| D.S. Pumps Ltd | Manufacturing | 2005 |
| Daizee Studios Ltd | Wholesale & retail | 2024 |
| Dara Developments Limited | Real estate | 2014 |
| Dash Inc Ltd | Manufacturing | 2013 |
| David Beck Consulting Limited | Professional & scientific | 2018 |
| David Montgomery Electrical Services Limited | Professional & scientific | 2013 |