| Chambers Property Consultants Ltd | Real estate | 2019 |
| Changeworks Consulting Ltd | Professional & scientific | 2025 |
| Changing Places Project Ltd | Construction | 2016 |
| Charis Capital Management Limited | Financial services | 2015 |
| Cherry Valley Farming Limited | Agriculture & fishing | 2017 |
| Cherry Valley Qnostics Limited | Manufacturing | 2018 |
| Cherryvale Limited | Professional & scientific | 2009 |
| CHL Contracts Ltd | Transport & logistics | 2021 |
| Ciaran Mcavoy Electrical Ltd | Construction | 2026 |
| Cipa Ltd | Financial services | 2020 |
| City Pads (UK) Ltd | Construction | 2013 |
| CK Software Ltd | Information & communication | 2016 |
| CKM Plastering Limited | Construction | 2020 |
| Clanconnel Home Care Limited | Health & social care | 2018 |
| Clarke Electrical & Sons Limited | Construction | 2018 |
| Classic Malts Limited | Wholesale & retail | 2011 |
| Clearhill Enterprises Limited | Arts & recreation | 1992 |
| Clearhill Estates Limited | Professional & scientific | 2019 |
| Clements Engineer Assessors Ltd | Wholesale & retail | 2016 |
| Clements Medical Services Ltd | Health & social care | 2024 |
| Clements Vehicle Inspections Limited | Wholesale & retail | 2024 |
| Cliffgar Ltd | Health & social care | 2022 |
| Cloney Contracts Limited | Construction | 2013 |
| Clydeair Ltd | Real estate | 2011 |
| CM Interior Design Ltd | Professional & scientific | 2022 |
| CMS Global Limited | Administrative & support | 2009 |
| Comfi Feet Podiatry Ltd | Health & social care | 2024 |
| Commercial Excellence Limited | Financial services | 2010 |
| Comotion Mobility Solutions Ltd | Wholesale & retail | 2024 |
| Complete Industrial Solutions Limited | Manufacturing | 2021 |
| Concept Occupational Health Ltd | Professional & scientific | 2024 |
| Connecting Minds Project | Education | 2023 |
| Controls Process & Automations Limited | Professional & scientific | 2021 |
| Coolnacran Farm Ltd | Agriculture & fishing | 2020 |
| Corbally Dairy Farm Ltd | Agriculture & fishing | 2021 |
| Corbally EGG Farm Ltd | Wholesale & retail | 2024 |
| Corbally Poultry Farm Ltd | Agriculture & fishing | 2014 |
| Corbey Ltd | Construction | 2017 |
| Cosby Limited | Administrative & support | 2007 |
| Costello's Hill Limited | Real estate | 2025 |
| Court Finance Limited | Financial services | 1982 |
| Cowan Haulage Ltd | Transport & logistics | 2005 |
| Craftstone Ltd | Extraterritorial | 2018 |
| Creevy House Farm Ltd | Agriculture & fishing | 2021 |
| Croobview Ltd | Financial services | 2022 |
| Crothers Lettings Ltd | Construction | 2025 |
| CTL Specialist Joinery Services Ltd | Manufacturing | 2024 |
| Cutting Edge Designs Newry Ltd | Administrative & support | 2025 |
| CW Propco Limited | Real estate | 2025 |
| CYH Business Consultancy Limited | Professional & scientific | 2014 |
| D Mcmullan Chimney & Stove Services Ltd | Administrative & support | 2026 |
| D Topley & Co Ltd | Professional & scientific | 2007 |
| D-Tech Design Ltd | Professional & scientific | 2001 |
| D.M.P.F. Developments Ltd | Real estate | 2015 |
| D.R Farms Limited | Agriculture & fishing | 2023 |
| D.S. Rogers Limited | Wholesale & retail | 2012 |
| D7 RGF Limited | Extraterritorial | 2012 |
| Dada Life Ltd | Wholesale & retail | 2024 |
| Daintree Investments Limited | Real estate | 2023 |
| Damien Trolan Ltd | Construction | 2005 |
| Daniva Developments Limited | Professional & scientific | 2016 |
| Dark Forest Theatre Ltd | Administrative & support | 2022 |
| Dask Timber Products Limited | Manufacturing | 1973 |
| Datacni Limited | Construction | 2013 |
| David Brown Inspection Services Ltd | Mining & quarrying | 2013 |
| David Morton Mortgages Limited | Financial services | 2026 |
| DB Investments N.I. Ltd | Real estate | 2022 |
| Dcfi Limited | Real estate | 2025 |
| DCM Contracts (NI) Limited | Construction | 2016 |
| Dean Contracts Limited | Construction | 2023 |
| Deans Wood (Richhill) Management Limited | Households | 2022 |
| Declan Diamond Design Ltd | Professional & scientific | 2018 |
| Deepee Limited | Construction | 2005 |
| Derek Faulkner Contracts Ltd | Construction | 2011 |
| DF Management (NI) Limited | Real estate | 2013 |
| Digi-Fone Limited | | 1996 |
| Digital Designs Print & Embroidery Limited | Manufacturing | 2024 |
| Digney Canavan Mccartan Limited | Financial services | 2024 |
| Direct Hardware Supplies Ltd | Wholesale & retail | 2012 |
| Discount Decorating Banbridge Ltd | Wholesale & retail | 2026 |
| Disnation Ltd | Wholesale & retail | 2019 |
| Diversitec Ltd | Professional & scientific | 2002 |
| Diviron Ltd | Professional & scientific | 2022 |
| DJL Commercial Haulage (NI) Limited | Transport & logistics | 2020 |
| DJL Surveyors Ltd | Professional & scientific | 2020 |
| DMAC82 Ltd | Construction | 2026 |
| Dmcg Agri Limited | Agriculture & fishing | 2022 |
| Dmnp Estates Ltd | Real estate | 2022 |
| Domino Developments Limited | Professional & scientific | 2006 |
| Donaghy Shoes Limited | Wholesale & retail | 2012 |
| Donaldson Developments Ltd | Construction | 2005 |
| Doral Construction Limited | Construction | 1975 |
| Doral Contracts Limited | Construction | 2013 |
| Dorans Hill Limited | Construction | 2016 |
| Down Autograss Ltd | Arts & recreation | 2024 |
| Down Leisure Limited | Wholesale & retail | 2023 |
| Downshire Marketing Ltd | Professional & scientific | 2025 |
| Downshire Propco Limited | Real estate | 2014 |
| Doyles Ventures Ltd | Households | 2025 |
| DPD Estimating Services Ltd | Construction | 2021 |