| Celandine Investments Limited | Real estate | 2017 |
| Cenpak Holdings Limited | Wholesale & retail | 2026 |
| Censer Perfumes Limited | Manufacturing | 2026 |
| Centre Electrical Services Ltd | Manufacturing | 2013 |
| Centre for Contemporary Art Derry-Londonderry Ltd | Arts & recreation | 2001 |
| Centreline Assets Limited | Real estate | 2026 |
| Centreline Brickworks Limited | Construction | 2019 |
| Certifia Limited | Professional & scientific | 2024 |
| Cfcp Limited | Professional & scientific | 2025 |
| CG Radiology Reports Ltd | Health & social care | 2020 |
| CGN Motors Ltd | Wholesale & retail | 2025 |
| Chapel Street Projects Ltd | Real estate | 2022 |
| Charcoal Grill House Ltd | Hospitality | 2025 |
| Charles Leisure Limited | Extraterritorial | 2015 |
| Charline Care Homes Limited | Health & social care | 2001 |
| Chartered Software Limited | Information & communication | 1989 |
| Chasing Light Tours Ltd | Professional & scientific | 2025 |
| Chcb Ltd | Other services | 2020 |
| Chen Yang Limited | Wholesale & retail | 2023 |
| Cherrydene Developments Ltd | Construction | 2001 |
| Chester Project Services Ltd | Professional & scientific | 2018 |
| Chestnut Grove Estates Limited | Construction | 2008 |
| Chicken Plaza Derry Ltd | Hospitality | 2021 |
| Chicken Plaza Limavady Ltd | Hospitality | 2025 |
| Children in Crossfire | Health & social care | 2005 |
| Chilis Restaurant Limited | Hospitality | 2025 |
| China Garden Yang Ltd | Hospitality | 2023 |
| China Kitchen 8886 Limited | Hospitality | 2025 |
| Christysdistributions Ltd | Wholesale & retail | 2025 |
| Churches' Enterprise Limited-The | Extraterritorial | 1992 |
| Churches' Training Company Ltd -the | Education | 1993 |
| Churches' Trust Limited -the | Other services | 1993 |
| Chuthulutrading Ltd | Wholesale & retail | 2023 |
| Cinecass Ltd | Professional & scientific | 2026 |
| Circle Advisory Unlimited | Professional & scientific | 2022 |
| Citpng Kwegb Ltd | Wholesale & retail | 2024 |
| City Competitions Limited | Arts & recreation | 2025 |
| City Dance Derry Ltd | Arts & recreation | 2022 |
| City Hotel Derry Ltd | Hospitality | 2023 |
| City Nails Spa & Beauty Limited | Other services | 2025 |
| City of Derry Accommodation Ltd | Extraterritorial | 2018 |
| City of Derry Farm CIC | Education | 2026 |
| City Plant Hire Limited | Administrative & support | 2016 |
| City Turkish Barber Derry Ltd | Other services | 2025 |
| City Windows & Doors Ltd | Extraterritorial | 2020 |
| CJC Campbell Ltd | Real estate | 2026 |
| CJC Investment Properties NI Limited | Real estate | 2022 |
| Cjcs Contracts Limited | Construction | 2024 |
| CJD Integrations Ltd | Information & communication | 2025 |
| CJF Drylining Limited | Construction | 2015 |
| CJL Design Ltd | Professional & scientific | 2021 |
| CK Business & Agri Finance Ltd | Financial services | 2026 |
| Ckpd Limited | Professional & scientific | 2018 |
| CL Bookkeeping Services Ltd | Professional & scientific | 2023 |
| Claims 4 U Loss Assessors Limited | Administrative & support | 2012 |
| Clann and Co Community Ltd | Arts & recreation | 2026 |
| Clann Limited | Professional & scientific | 2023 |
| Clannai Ltd | Information & communication | 2025 |
| Claragh Testing Ltd | Information & communication | 2025 |
| Claremont QQA Limited | Real estate | 2017 |
| Clarence Avenue Community Group Limited | Households | 2020 |
| Clarence Property Ventures Ltd | Real estate | 2017 |
| Clarendon International Facilities Management Limited | Administrative & support | 2012 |
| Clarendon Manor Management Services Limited | Households | 1999 |
| Clarke Quarries Ltd | Mining & quarrying | 2016 |
| Claud Trading Ltd | Wholesale & retail | 2018 |
| Claudes Catering Ltd | Hospitality | 2022 |
| Claudy Limited | Real estate | 2022 |
| Claudy Tiles Ltd | Construction | 2014 |
| Claudy Tyre Centre Ltd | Wholesale & retail | 2020 |
| CLD Property Ltd | Real estate | 2023 |
| Clean "N" Press Ltd | Other services | 2007 |
| Clean Point Solutions Ltd | Administrative & support | 2018 |
| Clean Water for Homes Ltd | Manufacturing | 2022 |
| Clear Autos Ltd | Wholesale & retail | 2025 |
| CLH Farms Ltd | Agriculture & fishing | 2025 |
| Click Corporate Limited | Wholesale & retail | 2022 |
| Click, Shop & Drop Limited | Hospitality | 2024 |
| Clifford Car Sales Ltd | Wholesale & retail | 2023 |
| Clinic 19 Ltd | Real estate | 2023 |
| Clinmara Consultancy Ltd | Professional & scientific | 2025 |
| Clipper Quay Riverfront Management Company Limited | Administrative & support | 2002 |
| Clipper Quay Street Limited | Hospitality | 2024 |
| Cloco Developments Ltd | Real estate | 2025 |
| Cloncool 9 Ltd | Professional & scientific | 2012 |
| Clooney Consulting Limited | Professional & scientific | 2022 |
| Clooney Enterprises Ltd | Real estate | 2021 |
| Clooney Estate Residents Association | Other services | 2008 |
| Clooney FC Community Sports Limited | Arts & recreation | 2013 |
| Clooney Investments Limited | Real estate | 2023 |
| Clooney Meats Ltd | Wholesale & retail | 2015 |
| Clooney Park Gardens Limited | Real estate | 2014 |
| Clooney Strand Retail Services Ltd | Wholesale & retail | 2026 |
| Cloontagh Property Group Ltd | Real estate | 2025 |
| Clothing Connected Ltd | Information & communication | 2024 |
| Cloudni Ltd | Information & communication | 2020 |
| Cloudwine Ltd | Wholesale & retail | 2023 |
| Cloudworks Consulting Limited | Information & communication | 2023 |
| Clover Limited | Professional & scientific | 2012 |
| Clsc Property Limited | Real estate | 2023 |