| Cahir Linn Oysters Limited | Agriculture & fishing | 2017 |
| Cairn Grove Management Co Ltd | Households | 2007 |
| Cairn Hill Home a Limited | Administrative & support | 1989 |
| CAL Electrical Services Ltd | Construction | 2019 |
| Calculass Limited | Financial services | 2021 |
| Calibration Laboratory Limited | Professional & scientific | 2021 |
| Calibration NI Ltd | Wholesale & retail | 2025 |
| Calm Cosmetic Skin Care Clinic Ltd | Health & social care | 2017 |
| Calm Tides Wellbeing CIC | Health & social care | 2025 |
| Calma Health | Health & social care | 2017 |
| Calmbee Ltd | Information & communication | 2021 |
| Calmdon Ltd | Professional & scientific | 2014 |
| Calmor Properties Limited | Construction | 2003 |
| Calmor Timber Limited | Manufacturing | 2025 |
| Calmount Investments Limited | Real estate | 2019 |
| Camen Capital NI Ltd | Wholesale & retail | 2026 |
| Camish Utilities Limited | Transport & logistics | 2026 |
| Camlough Community Association Limited | Arts & recreation | 2009 |
| Camlough Contracts & Co Limited | Construction | 2018 |
| Camlough Electrical Appliance Centre Ltd | Wholesale & retail | 2006 |
| Camlough GC Ltd | Wholesale & retail | 2021 |
| Camlough Lake Adventure Ltd | Administrative & support | 2025 |
| Camlough Metals Ltd | Wholesale & retail | 2015 |
| Camlough Nursery Ltd | Wholesale & retail | 2025 |
| Camlough Pharmacy Limited | Wholesale & retail | 2016 |
| Camlough Restoration Repair Contractors Ltd | Construction | 2024 |
| Camlough Rovers Football Club | Arts & recreation | 2015 |
| Campbell and Grant Solicitors Limited | Professional & scientific | 2020 |
| Campbell Transport Ltd | Transport & logistics | 2016 |
| CAMPERHIRE4U Ltd | Administrative & support | 2020 |
| Camphill Social Fund (N.I.) | Other services | 1968 |
| Camsaw Distribution Ltd | Wholesale & retail | 2019 |
| Camtech Solutions Ltd | Information & communication | 2024 |
| Camtek IT Limited | Information & communication | 2021 |
| Canal Communications Ltd | Information & communication | 2019 |
| Canavan Engineering Solutions Ltd | Professional & scientific | 2023 |
| CANDU2 Ltd | Wholesale & retail | 2020 |
| Canewpoint Limited | Real estate | 2018 |
| Cann Properties (1) Ltd | Real estate | 2018 |
| Cann Properties Ltd | Real estate | 2014 |
| Cann Scaff Ltd | Construction | 2021 |
| Canning Plant Services Ltd | Wholesale & retail | 2025 |
| Canon Estates Limited | Construction | 1988 |
| Capacityconcepts Limited | Hospitality | 2013 |
| Capall Solutions Limited | Construction | 2015 |
| Capital Machinery Services Limited | Manufacturing | 2015 |
| Cappy Trading Ltd | Wholesale & retail | 2026 |
| Cappy Wines & Spirits Ltd | Hospitality | 2015 |
| Capsure Tax Management Limited | Professional & scientific | 2012 |
| Captain Greens Craigavon Ltd | Arts & recreation | 2018 |
| Captain Greens Ltd | Arts & recreation | 2018 |
| Car Sales Distribution Ltd | Wholesale & retail | 2014 |
| Cara IRL Ltd | Wholesale & retail | 2024 |
| Caraderm Limited | Extraterritorial | 1991 |
| Carbery House Limited | Wholesale & retail | 2015 |
| Carbon First Ltd | Manufacturing | 2018 |
| Carcullion Properties Limited | Construction | 2011 |
| Cardiac Care Ireland | Health & social care | 2022 |
| Care for People (N.I.) Ltd | Real estate | 2021 |
| Care Home Spare Parts Ltd | Health & social care | 2026 |
| Careforsons Northern Ireland Limited | Wholesale & retail | 2021 |
| Carepay Solutions Limited | Information & communication | 2024 |
| Cargie Construction Ltd | Construction | 2024 |
| Carlingford Lough Mussels Limited | Administrative & support | 1988 |
| Carlingford Lough Yacht Club Limited | Arts & recreation | 2014 |
| Carlingford Oyster Company (N.I.) Limited | Agriculture & fishing | 2019 |
| Carlingford Vision Ltd | Financial services | 2026 |
| Carlinn Transport N.I. Limited | Professional & scientific | 2018 |
| Carlinn's Cove Management Company Limited | Households | 2000 |
| Carmac Limited | Arts & recreation | 2018 |
| Carmave Properties Limited | Real estate | 2001 |
| Carn Hill Livestock Ltd | Agriculture & fishing | 2024 |
| Carna Industrial Engineering Ltd | Professional & scientific | 2013 |
| Carnation Capital LP | | 2017 |
| Carnbane Customs Clearance Ltd | Transport & logistics | 2021 |
| Carnbane Estates Limited | Construction | 2014 |
| Carnbane Health Limited | Financial services | 2018 |
| Carnbane Meadow Limited | Real estate | 2016 |
| Carncastle Properties Limited | Agriculture & fishing | 2009 |
| Carnegie Construction IRE Ltd | Construction | 2026 |
| Carneyhaugh Court Management Company Limited | Households | 2008 |
| Carnglen Properties Limited | Real estate | 2024 |
| Carnhill Homes Limited | Construction | 2017 |
| Carnmeen Developments Limited | Professional & scientific | 2010 |
| Carnmeen Energy Limited | Other services | 2008 |
| Carnvalley Management Company Limited | Households | 2002 |
| Carnview Construction (NI) Ltd | Construction | 2013 |
| Caroline Benson Medical Ltd | Other services | 2023 |
| CAROUSELS4EVENTS Ltd | Arts & recreation | 2017 |
| Carr Contracts Ltd | Construction | 2019 |
| Carragher Fuels Ltd | Wholesale & retail | 2013 |
| Carragher Oils Limited | Wholesale & retail | 1994 |
| Carragher Tyre Sales Limited | Wholesale & retail | 2006 |
| Carraig Mhuire Management Company Limited | Households | 2006 |
| Carraigh DUA Services Ltd | Wholesale & retail | 2016 |
| Carrclo Limited | Financial services | 2020 |
| Carrick & Leck Ltd | Construction | 2021 |
| Carrick Brae Contracts (NI) Ltd | Construction | 2024 |
| Carrick Chemicals Ltd. | Agriculture & fishing | 2017 |
| Carrick Contracts Holdings Ltd | Financial services | 2023 |