| C & R Wines Limited | Wholesale & retail | 2012 |
| C.N Developments Limited | Construction | 1997 |
| CAF Haulage & Recovery Limited | Transport & logistics | 2024 |
| Cameron Cars NI Ltd | Wholesale & retail | 2020 |
| Campbell Adams Consulting Limited | Professional & scientific | 2003 |
| Capecastle Lime Works Limited | Extraterritorial | 1941 |
| Carmichael Cars Ltd | Wholesale & retail | 2007 |
| Carnaff Ltd | Construction | 2014 |
| Carrow Construction Limited | Construction | 2023 |
| Carrowcrin Limited | Construction | 2013 |
| Carsena Bloodstock Ltd | Agriculture & fishing | 2024 |
| Carsena Management Services Ltd | Professional & scientific | 2017 |
| Carua Project Engineering Ltd | Construction | 2014 |
| Castlecatt Properties Limited | Real estate | 2021 |
| Castletown Property (NI) Ltd | Real estate | 2026 |
| Causeway Coast & Glens Aims | Education | 2017 |
| Causeway Coast and Glens Heritage Trust Limited | Professional & scientific | 2002 |
| Causeway Coast Caravan Sales Ltd | Wholesale & retail | 2025 |
| Causeway Coast Security Solutions Ltd | Administrative & support | 2024 |
| Causeway Coffee Limited | Wholesale & retail | 2018 |
| Causeway Crafters NI Ltd | Wholesale & retail | 2024 |
| Causeway Geotech Limited | Construction | 2012 |
| Causeway Holdings Limited | Wholesale & retail | 2015 |
| Causeway Pallets & Transport Limited | Transport & logistics | 2004 |
| Causeway Property Assets Ltd | Real estate | 2024 |
| Causeway Publishing Limited | Manufacturing | 2012 |
| Ccght Enterprises Limited | Agriculture & fishing | 2025 |
| CDL Plant Hire Ltd | Administrative & support | 2019 |
| CEO Property Holdings Ltd | Financial services | 2020 |
| Chemworx Collection Ltd | Administrative & support | 2021 |
| Chestnutt Animal Feeds Limited | Manufacturing | 2010 |
| China Connections Consultant Limited | Professional & scientific | 2014 |
| China Garden Chen Limited | Hospitality | 2024 |
| Chips Inn Fast Food Ltd | Hospitality | 2026 |
| Christies Direct Ltd. | Wholesale & retail | 2005 |
| Claddagh Coffee Ltd | Hospitality | 2026 |
| Cleanscape Property Maintenance Ltd | Real estate | 2016 |
| Clearmount Limited | Professional & scientific | 2015 |
| Clifton Terrace Castlerock Management Company Limited | Households | 2026 |
| CML Building (Moneybrannon) Limited | Construction | 2019 |
| CN Timber Limited | Wholesale & retail | 2016 |
| Coast Carpentry & Interiors Ltd | Manufacturing | 2023 |
| Coast Contracts Ltd | Construction | 2023 |
| Coast to Coast Pet Supplies Ltd | Wholesale & retail | 2026 |
| Colin IAN Ross Studio Ltd | Professional & scientific | 2025 |
| Compass Advocacy Network Limited | Health & social care | 1997 |
| Complete Gyms Ltd | Wholesale & retail | 2024 |
| Connect Christian Fellowship | Other services | 2005 |
| Connolly Positech Ltd | Manufacturing | 2025 |
| Core Property Consultants Ltd | Real estate | 2017 |
| Country Real Estate Limited | Real estate | 2005 |
| Cowcare Systems Ltd | Manufacturing | 2011 |
| CRH Produce Limited | Wholesale & retail | 2025 |
| Crostini Enterprises Limited | Extraterritorial | 2013 |
| Cullycapple Developments Ltd | Construction | 2017 |
| CUT, Fold & Fabrication NI Ltd | Professional & scientific | 2021 |
| D & P Commercial Repairs Limited | Manufacturing | 2011 |
| D S Accounting Limited | Professional & scientific | 2025 |
| DAC Welding/Fabrication Ltd. | Construction | 2025 |
| Dalriada School | Education | 1925 |
| Damysus Trading Technologies Ltd | Information & communication | 2022 |
| Datinfra Ltd | Financial services | 2019 |
| David Mcmullan & Co Ltd | Professional & scientific | 2016 |
| DC Construction & Architectural Joinery Limited | Construction | 2026 |
| DC Construction (NI) Ltd | Construction | 2009 |
| Deepstown Rose Investments Limited | Financial services | 2023 |
| Delni Consulting Limited | Professional & scientific | 2022 |
| DG Mortgages Limited | Professional & scientific | 2017 |
| Digital Print & CNC Services Ltd | Manufacturing | 2016 |
| DMG Plumbing Services Ltd | Construction | 2015 |
| DMK Building & Surveying Services Limited | Professional & scientific | 2022 |
| DMT Contracts Ltd | Construction | 2025 |
| Donkey Comps Ltd | Wholesale & retail | 2024 |
| Dowey Fuels Ltd | Wholesale & retail | 2012 |
| DPC Homes Limited | Construction | 2012 |
| Drumabest Farm Ltd | Agriculture & fishing | 2020 |
| Drumk Developments Ltd | Construction | 2015 |
| Drumlee Energy Limited | Energy | 2025 |
| Drumlochart Caravan Sales Ltd | Wholesale & retail | 2005 |
| DRY Arch Limited | Wholesale & retail | 2008 |
| Ducati Antrim Ltd | Wholesale & retail | 2024 |
| Duff Engineering Ltd | Manufacturing | 2023 |
| Dunrunnin Ltd | Real estate | 2024 |
| Dynumo Ventures Limited | Information & communication | 2012 |
| E & L Construction Services Limited | Construction | 2017 |
| E Goudie Consulting Ltd | Administrative & support | 2022 |
| Eaglemount Developments Limited | Wholesale & retail | 2007 |
| Earls Harbour Ltd | Hospitality | 2025 |
| Earth TEC .1 Ltd | Construction | 2020 |
| Ebel Enterprises Ltd | Wholesale & retail | 2024 |
| Ecco Boutique Ltd | Wholesale & retail | 2022 |
| Eco Fresh Ventilation Ltd | Wholesale & retail | 2023 |
| EFS (NI) Limited | Wholesale & retail | 2014 |
| EFS Hydro DIP (NI) Limited | Wholesale & retail | 2020 |
| EFS Prestige Autos Ltd | Professional & scientific | 2022 |
| Eighty Promenade Management Company Limited | Households | 2026 |
| EJD Ecom Ltd | Wholesale & retail | 2024 |
| Eleveg Limited | Professional & scientific | 2022 |
| Eliteconnected.Ceg Limited | Education | 2023 |
| EMA Building & Civils Limited | Construction | 2020 |