| Como Lake Limited | Real estate | 2015 |
| Como Property Company Ltd | Real estate | 2013 |
| Como Real Estate Limited | Financial services | 2017 |
| Como Trading Limited | Real estate | 2015 |
| Compact Properties (NI) Limited | Real estate | 2003 |
| Company Administration Limited | Administrative & support | 2007 |
| Company Formations (Belfast) Limited | Other services | 2011 |
| Company Image Consultants Ltd | Professional & scientific | 1998 |
| Compass Agencies N.I Ltd | Health & social care | 2021 |
| Compass Audit Limited | Administrative & support | 2017 |
| Compass Coach Travel Ltd | Transport & logistics | 2024 |
| Compass Counselling C.I.C. | Health & social care | 2016 |
| Compass Financial Associates Limited | Financial services | 2002 |
| Compass Hill Contracts Ltd | Construction | 2023 |
| Compassion Belfast | Other services | 1993 |
| Compendium AF Ltd | Wholesale & retail | 2025 |
| Compendium Wine Merchants Limited | Extraterritorial | 1975 |
| Complete Accident Management Limited | Administrative & support | 2026 |
| Complete Clean Belfast Limited | Administrative & support | 2017 |
| Complete Construction Training Services Limited | Education | 2010 |
| Complete Control Lighting Ltd | Construction | 2017 |
| Complete Conveyor Services Ltd | Mining & quarrying | 2019 |
| Complete DC Ltd | Information & communication | 2024 |
| Complete Financial Ltd | Financial services | 2023 |
| Complete Health Rewire Ltd | Other services | 2022 |
| Complete Heat Pump Services Ltd | Construction | 2025 |
| Complete Joinery NI Ltd | Manufacturing | 2019 |
| Complete Origin Ltd | Financial services | 2026 |
| Complete Property Solutions N. Ireland Ltd | Construction | 2024 |
| Complete Renovation Solutions NI Ltd | Construction | 2018 |
| Complete Taste PVT Ltd | Hospitality | 2023 |
| Complete Tasty MIX NI Ltd | Hospitality | 2026 |
| Complete Van Solutions NI Ltd | Administrative & support | 2025 |
| Complex Chemicals & Supplies Ltd | Wholesale & retail | 2019 |
| Complex Paints Limited | Wholesale & retail | 2016 |
| Compliance and Sustainability Ltd | Information & communication | 2022 |
| Complyni Ltd | Administrative & support | 2017 |
| Computer Support (Ireland) Ltd | Information & communication | 1998 |
| Compval Trading & Services Ltd | Information & communication | 2012 |
| Comsults NI Limited | Professional & scientific | 2019 |
| Comtec Developments (NO.1) Limited | Real estate | 2017 |
| Comtec Developments Limited | Real estate | 1999 |
| Conael Shipping Services Limited | Administrative & support | 2020 |
| Conal Kielty Enterprises Limited | Manufacturing | 2016 |
| Conalave Consulting Limited | Professional & scientific | 2018 |
| Conard Care Services Limited | Health & social care | 2005 |
| Conca Trading Limited | Wholesale & retail | 2025 |
| Concal (NI) Limited | Professional & scientific | 2010 |
| Concentrix CVG Group Limited | Information & communication | 1995 |
| Concentrix Europe Limited | Administrative & support | 1999 |
| Concept Apps Ltd | Professional & scientific | 2015 |
| Concept Beverages (NI) Ltd | Wholesale & retail | 2020 |
| Concept Beverages Holdings Ltd | Wholesale & retail | 2020 |
| Concept Fire Solutions Limited | Professional & scientific | 2017 |
| Concept Services (NI) Ltd | Administrative & support | 2003 |
| Concept Tech INT. Ltd | Manufacturing | 2011 |
| Concept-Fitout Ltd | Administrative & support | 2015 |
| Conchur Construction Ltd | Professional & scientific | 2021 |
| CONCINNITY365 Ltd | Information & communication | 2025 |
| Concord Farms Limited | Agriculture & fishing | 2009 |
| Concord Mediation Limited | Professional & scientific | 2019 |
| Concrete Clouds Ltd | Professional & scientific | 2019 |
| Conduit Secretarial Limited | Professional & scientific | 2018 |
| Conekt Legal Ltd | Administrative & support | 2024 |
| Conexpo (NI) Limited | Mining & quarrying | 1991 |
| Coney Island Holiday Park Limited | Hospitality | 2025 |
| Confianza Technologies Ltd | Information & communication | 2019 |
| Confidentem Consulting Limited | Professional & scientific | 2023 |
| Confluence Solutions Ltd | Administrative & support | 2024 |
| Cong River Capital NI Limited | Financial services | 2025 |
| Cong River Communications Limited | Financial services | 2025 |
| Conkea.Com Ltd | Manufacturing | 2026 |
| Conker Rewarding Limited | Information & communication | 2026 |
| Conkerfox NI Limited | Information & communication | 2025 |
| Conkir Developments Ltd | Real estate | 2012 |
| Conlan Boxing Ltd | Arts & recreation | 2018 |
| Conlan Boxing Management Limited | Arts & recreation | 2025 |
| Conlan Sports Ltd | Arts & recreation | 2021 |
| Conlon Group Limited | Professional & scientific | 2019 |
| Conlon Pubs (Belfast) Limited | Hospitality | 2026 |
| Connect & Protect Financial Limited | Professional & scientific | 2012 |
| Connect 2 Counselling C.I.C. | Health & social care | 2014 |
| Connect Digital Communications Limited | Information & communication | 2024 |
| Connect Enterprise Business Unit (EBU) Ltd | Information & communication | 2022 |
| Connect Plumbers Limited | Construction | 2019 |
| Connect SF Support Ltd | Information & communication | 2025 |
| Connect Through Service Limited | Administrative & support | 2024 |
| Connected Academy Limited | Education | 2018 |
| Connected Health (Care NI) Limited | Health & social care | 1999 |
| Connected Health Alliance CIC | Other services | 2012 |
| Connected Health Domiciliary Care Limited | Health & social care | 2006 |
| Connected Health Limited | Health & social care | 2012 |
| Connected Living LAB Limited | Health & social care | 2018 |
| Connoisseur TOM Healthcare Ltd | Health & social care | 2024 |
| Connolly Longhurst (Estate Agents) Limited | Real estate | 2013 |
| Connolly White Consultancy Limited | Health & social care | 2022 |
| Connor & Sons Limited | Real estate | 1938 |
| Connor Kelly Ltd | Wholesale & retail | 2025 |
| Connor Mcateer Ltd | Wholesale & retail | 2025 |
| Connor's Doagh Limited | Extraterritorial | 2011 |