| CMB Ltd | Professional & scientific | 2003 |
| CMB Recruitment Belfast Limited | Administrative & support | 2015 |
| CMB Recruitment Ltd | Administrative & support | 2010 |
| Cmbd Limited | Information & communication | 2015 |
| CMC Properties (2026) Ltd | Real estate | 2026 |
| CMC Tax Limited | Professional & scientific | 2017 |
| CMC0 Holdings Limited | Financial services | 2026 |
| Cmcc Services Limited | Construction | 2016 |
| Cmcg Holdings Belfast Ltd | Manufacturing | 2025 |
| Cmcg Properties Ltd | Real estate | 2025 |
| Cmcl Imaging Ltd | Health & social care | 2025 |
| CMD (N.I.) Ltd | Other services | 2020 |
| CMD Management (N.I.) Limited | Professional & scientific | 2022 |
| CME Technology and Support Services Limited | Information & communication | 2011 |
| CMG Claims (UK) Ltd | Financial services | 2019 |
| CMG Consulting N.I. Ltd | Professional & scientific | 2025 |
| CMG Cunningham Dickey LLP | | 2018 |
| CMG Finance Ltd | Other services | 2023 |
| CMG Plant Limited | Wholesale & retail | 2014 |
| CMK Automotive Ltd | Administrative & support | 2026 |
| CMK Media Limited | Manufacturing | 2015 |
| CMK Plumbing and Heating (Belfast) Ltd | Construction | 2017 |
| CMK Productions Ltd | Information & communication | 2022 |
| CML Warranties Ltd | Extraterritorial | 2017 |
| Cmlaserandbeauty Ltd | Other services | 2026 |
| CMN Engineering Solutions Ltd | Manufacturing | 2019 |
| CMP Consulting Limited | Professional & scientific | 2025 |
| CMP Planning & Design Ltd | Professional & scientific | 2024 |
| Cmph Properties Ltd | Real estate | 2024 |
| Cmpr Property Ltd | Real estate | 2017 |
| CMR Security Systems Ltd | | 1998 |
| Cmrc Dental Ltd | Health & social care | 2024 |
| CMS Mechanical Services Ltd | Construction | 2021 |
| CMS Restoration Limited | Construction | 2018 |
| CN Pro Repair Ltd | Manufacturing | 2025 |
| CN90 Ltd | Hospitality | 2023 |
| CN91 Ltd | Hospitality | 2024 |
| Cnag Teoranta Limited | Education | 2016 |
| Cnber Global Ltd | Transport & logistics | 2025 |
| CND Joinery & Flooring Ltd | Construction | 2024 |
| CNG Catering Ltd | Hospitality | 2025 |
| CNL Contracts Ltd | Construction | 2018 |
| Co-Operation Ireland | Health & social care | 1982 |
| Co-Operation Ireland Events Limited | Administrative & support | 1999 |
| CO3 Chief Officers Third Sector | Other services | 1999 |
| CO3 Enterprises Ltd | Professional & scientific | 2018 |
| Coach Travel Ireland Ltd | Transport & logistics | 2023 |
| Coached Plus Ltd | Arts & recreation | 2018 |
| Coachfinish (NI) Ltd | Wholesale & retail | 1974 |
| Coachsmith Ltd | Education | 2024 |
| Coan Consult Ltd | Construction | 2020 |
| Coast Fitness CIC | Arts & recreation | 2022 |
| Coastal Baptist Limited | Other services | 2024 |
| Coastal Clear Water (Holdings) Limited | Extraterritorial | 1999 |
| Coastal Clear Water Limited | Water & waste | 1995 |
| Coastal Container Line Limited | Transport & logistics | 1978 |
| Coastguard Developments Ltd | Administrative & support | 2014 |
| Coastline Heat Ltd | Construction | 2025 |
| Coastways Records Management Ltd | Transport & logistics | 2014 |
| Coastways Storage and Removals Limited | Transport & logistics | 1999 |
| Cobain Group Limited | Administrative & support | 2015 |
| Cobain Holdings Limited | Financial services | 2022 |
| Cobain Invest Co 2 Limited | Financial services | 2021 |
| Cobain Invest Co Limited | Transport & logistics | 2021 |
| Cobblers ROW Management Company Limited | Households | 2008 |
| Cobra Automation Limited | Extraterritorial | 2011 |
| Cobra Bidco Limited | Information & communication | 2015 |
| Cobra Midco Limited | Information & communication | 2015 |
| Cobra Topco Limited | Information & communication | 2015 |
| Cobro Limited | Hospitality | 2023 |
| Cobuy Qmall Limited | Wholesale & retail | 2025 |
| COC Aistriuchan Ltd | Professional & scientific | 2024 |
| Cocktail KEG Company Ltd | Manufacturing | 2019 |
| Coco Socials Studio Ltd | Professional & scientific | 2022 |
| Cocoon.Systems Limited | Manufacturing | 2025 |
| Code 15 Pizza Ltd | Hospitality | 2024 |
| Code Art LP | | 2016 |
| Code Fifteen Ltd | Wholesale & retail | 2025 |
| Codeaim Limited | Information & communication | 2017 |
| Codec-Dss Ltd | Information & communication | 2015 |
| Codefixer Ltd | Professional & scientific | 2023 |
| Codeseek Limited | Information & communication | 2023 |
| Coding Group Ltd | Information & communication | 2021 |
| Codiopert Ltd | Wholesale & retail | 2024 |
| Codzilla Ltd | Hospitality | 2020 |
| Coenco Limited | Information & communication | 2025 |
| Coey and Johnston (Holdings) Limited | Real estate | 1978 |
| Coffe Management LP | | 2018 |
| Coffee & Co N.I Ltd | Manufacturing | 2025 |
| Coffee & Heroes Ltd | Wholesale & retail | 2017 |
| Coffee @the Castle Limited | Hospitality | 2019 |
| Coffee Black Belfast Limited | Administrative & support | 2017 |
| Coffee Technology Ltd | Manufacturing | 2025 |
| Coffee Vending NI Limited | Wholesale & retail | 2021 |
| Coffeys Finaghy Limited | Wholesale & retail | 2021 |
| Coffeys Lisburn Road Limited | Wholesale & retail | 2021 |
| Coflip Ltd | Information & communication | 2024 |
| COG Training Ltd | Education | 2019 |
| Cogent Management Consulting LLP | | 2009 |
| Cogito Consultancy Ltd. | Information & communication | 2019 |