| Cognisense Ltd | Professional & scientific | 2018 |
| Coherence Audio Ltd | Arts & recreation | 2023 |
| Coin Cufflinks Limited | Wholesale & retail | 2023 |
| Coinvine Industries LP | | 2018 |
| Cois Locha Management Company Limited | Real estate | 2005 |
| Coiste Irish Political Tours C.I.C. | Administrative & support | 2016 |
| Coiste NA N-Iarchimi | Other services | 1999 |
| COL MAR Bangor Limited | Real estate | 2015 |
| Cold Plus Limited | Manufacturing | 2023 |
| Coldice Limited | Real estate | 2020 |
| Colebrook Developments Limited | Real estate | 2007 |
| Colenso Apartments Limited | Extraterritorial | 1982 |
| Colenso Medical Limited | Wholesale & retail | 2020 |
| Coleraine Business & Trade Centre Limited | Households | 2003 |
| Coleraine Distillery Limited | Administrative & support | 1974 |
| Coleraine Joinery Limited | | 1998 |
| Colfuline Technology Limited | Wholesale & retail | 2025 |
| Colhountech Limited | Information & communication | 2016 |
| Colily Limited | Wholesale & retail | 2024 |
| Colin Backus Ltd | Wholesale & retail | 2025 |
| Colin Bridge Community Interest Company | Other services | 2020 |
| Colin Buchanan and Partners Limited | | 2006 |
| Colin Glen Trust | Administrative & support | 1991 |
| Colin House & Home Ltd | Wholesale & retail | 2021 |
| Colin James O Neill Ltd | Extraterritorial | 2022 |
| Colin Joshua Greer Ltd | Wholesale & retail | 2022 |
| Colin Lavery TM Ltd | Construction | 2023 |
| Colin Lurring Ltd | Wholesale & retail | 2025 |
| Colin Neighbourhood Partnership | Other services | 2003 |
| Colin Neighbourhood Sure Start Project | Other services | 2001 |
| Colin T Farr Limited | Arts & recreation | 2020 |
| Colinglen Contractors Limited | Water & waste | 2002 |
| Colinglen Fuels Depot Limited | Wholesale & retail | 2017 |
| Colinwell Masonry Products Holdings Limited | Financial services | 2021 |
| Colinwell Masonry Products Limited | Manufacturing | 2021 |
| Collateral Property Limited | Real estate | 2006 |
| College Court Central Management Company Limited | Real estate | 2007 |
| College Mews Apartments Limited | Extraterritorial | 2003 |
| College Park Management Company Limited | Extraterritorial | 2008 |
| College Square North Management Company Limited | Extraterritorial | 2004 |
| College Street Caffe Ltd | Hospitality | 2018 |
| Collette Creative Photography Ltd | Professional & scientific | 2023 |
| Colliers Belfast Ltd | Real estate | 2012 |
| Colliers N.I. Residential Limited | Real estate | 2016 |
| Collinbridge Finance Ltd | Professional & scientific | 2011 |
| Collinbridge Holdings Ltd | Financial services | 2010 |
| Collins Property Developments Ltd | Real estate | 2014 |
| Collins Rolston Architects Ltd | Professional & scientific | 2015 |
| Collinward Healthcare Ltd | Wholesale & retail | 2021 |
| Collision Impact Services Ltd | Wholesale & retail | 2021 |
| Colmantex Export LP | | 2018 |
| Color Master Tech Limited | Wholesale & retail | 2025 |
| Colorado Holdings Limited | Financial services | 2020 |
| Colorfulworld Ltd | Hospitality | 2018 |
| Colorite Europe Limited | Manufacturing | 1996 |
| Colotex Industries LP | | 2017 |
| Colour Investments Ltd | Financial services | 2006 |
| Colour Ventures Limited | Information & communication | 2008 |
| Colourhouse International Ireland Ltd | Other services | 2021 |
| Colpany Ltd | Wholesale & retail | 2025 |
| Colthurst Card & Payment Solutions (UK) Ltd | Professional & scientific | 2018 |
| Colton Quarries Limited | Mining & quarrying | 2004 |
| Columbanus Enterprises Limited | Other services | 1988 |
| Colwena Holdings Limited | Financial services | 2024 |
| Comac Ltd | Manufacturing | 2019 |
| Combat Robotics NI CIC | Education | 2025 |
| Combohq Ltd | Administrative & support | 2026 |
| Comcentris Ltd | Information & communication | 2007 |
| Comco Holdings Limited | Financial services | 2022 |
| Comco Plastics (Belfast) Limited | Wholesale & retail | 2011 |
| Come for Best Limited | Wholesale & retail | 2025 |
| Comedy Séance Ltd | Information & communication | 2024 |
| Comerton & Hill Solicitors Limited | Professional & scientific | 2014 |
| Comfort & Rest Ltd Ltd | Manufacturing | 2023 |
| Comfort Afro/Caribbean Grocery Store Ltd | Wholesale & retail | 2025 |
| Comhairle NA Gaelscolaiochta | Education | 2000 |
| Comhar Training Limited | Financial services | 2017 |
| Commander Prompt Limited | Information & communication | 2018 |
| Commedia of Errors | Education | 2021 |
| Commercial Catering Solutions Ltd | Other services | 2019 |
| Commercial Court Inns Limited | Hospitality | 1984 |
| Commercial Print Solutions Limited | Manufacturing | 2013 |
| Commissioning Partners Limited | Professional & scientific | 2025 |
| Committee on the Administration of Justice Ltd-The | Other services | 1997 |
| Common Ground Enterprises Limited | Professional & scientific | 2026 |
| Common Youth Ltd | Public administration | 1993 |
| Commons Brae Developments Ltd | Construction | 2003 |
| Commonwealth Games Northern Ireland Ltd. | Arts & recreation | 1998 |
| Commprop Link Ltd | Financial services | 2021 |
| Communication Club Limited | Health & social care | 2018 |
| Communicorp UK Limited | Information & communication | 2013 |
| Community Calling Ltd | Extraterritorial | 2020 |
| Community Developers Initiative Limited | Education | 2015 |
| Community Energy NI (Ceni) Limited | Education | 2026 |
| Community Football Company CIC | Education | 2022 |
| Community Garden Support Ltd | Other services | 2025 |
| Community Multisport CIC | Arts & recreation | 2014 |
| Community Perks Limited | Other services | 2018 |
| Community Restorative Justice Ireland | Other services | 2002 |
| Community Sports Network Ltd | Arts & recreation | 2006 |