| Craignamara Limited | Hospitality | 2013 |
| Cranagh Hill Ltd | Real estate | 2005 |
| Cranagh Leisure Ltd | Hospitality | 2017 |
| Crannagh Activity Centre Limited | Arts & recreation | 2017 |
| Crannyview Management Limited | Extraterritorial | 2001 |
| Crawford Square Management Company Limited | Households | 2003 |
| Creative Logic Solutions Limited | Wholesale & retail | 1999 |
| Creatures From the North Ltd | Wholesale & retail | 2025 |
| Crepe N Dough 2024 Ltd | Hospitality | 2025 |
| CRH Properties Ltd | Real estate | 2022 |
| Crindle Limited | Extraterritorial | 1998 |
| Croasdailes LLP | | 2015 |
| Crop Specialists (N.I.) Limited | Extraterritorial | 1993 |
| Crow's Nest Community Playgroup - the | Education | 2000 |
| Crusoes Catering Ltd | Hospitality | 2024 |
| Cryoclean Solutions NI Ltd | Manufacturing | 2026 |
| CTS (Embroidery) Ltd | Manufacturing | 2013 |
| Cuilbane Project 2 Limited | Other services | 2025 |
| Cunning Consultancy Ltd | Professional & scientific | 2014 |
| Curran Holding Limited | Financial services | 2018 |
| Currie Engineering (Garvagh) Limited | Manufacturing | 2010 |
| Currie Engineering (Holdings) Limited | Financial services | 2018 |
| Currie Fabtech (Holdings) Limited | Financial services | 2017 |
| Currie Fabtech Limited | Manufacturing | 2018 |
| Curtis Developments Ltd. | Wholesale & retail | 1996 |
| D.A. Stewart Accident Repairs | Wholesale & retail | 2007 |
| DAC Contracts (NI) Limited | Construction | 2014 |
| Daisy MAE NI Ltd | Wholesale & retail | 2024 |
| Dalriada Hall Management Company Ltd. | Households | 2016 |
| Dan-Matt Taverns Limited | Hospitality | 2015 |
| Dander and Santer C.I.C. | Health & social care | 2026 |
| Daniel Henry (Coleraine) Limited | Extraterritorial | 2009 |
| Daniel Henry (Derry) Limited | Real estate | 2008 |
| Daniel Henry Limited | Professional & scientific | 2009 |
| Daniel Mccormick Amusement Limited | Arts & recreation | 2021 |
| Darah Enterprises Ltd | Administrative & support | 2024 |
| Darraghs Accountancy Ltd | Professional & scientific | 2017 |
| David Coils Ltd | Wholesale & retail | 2021 |
| David Mcintyre Autobody & Alloys Ltd | Wholesale & retail | 2024 |
| Davil Properties Limited | Construction | 2008 |
| Davison Contracts (N.I.) Limited | Manufacturing | 2015 |
| Dawn-Pak (Derry) Limited | | 1973 |
| Dawson Street Capital Limited | Real estate | 2014 |
| DD Quayside Limited | Real estate | 2020 |
| Deadlift Energy Ltd | Manufacturing | 2025 |
| Deadly Digital Studios Limited | Information & communication | 2025 |
| Decodon Group Ltd | Financial services | 2024 |
| Decodon Ltd | Real estate | 2021 |
| Deerpark Property Management Company Limited | Administrative & support | 2015 |
| Define Developments Ltd | Construction | 2024 |
| DEH Plant Hire Ltd | Construction | 2001 |
| Deighan Construction Surveys Ltd | Professional & scientific | 2022 |
| Deighan Holdings Limited | Hospitality | 2006 |
| Deighan Transport Limited | Transport & logistics | 2016 |
| Deliberate Learning Limited | Education | 2018 |
| Delwyn Colley Electrical Services Ltd | Manufacturing | 2013 |
| Derry Hotel Trading Limited | | 1995 |
| Derrycourtney Manor Management Ltd | Households | 2021 |
| Derson Properties Limited | Extraterritorial | 2002 |
| Devenish Manor Gatelodge's Ltd | Extraterritorial | 2006 |
| DG E-Trading Ltd | Wholesale & retail | 2019 |
| Diamond Build Services Ltd | Construction | 2020 |
| Diamond Property Ltd | Real estate | 2015 |
| Dibanto Ltd | Health & social care | 2021 |
| Digital Financial Solutions Ltd | Extraterritorial | 2022 |
| Dinki Ltd | Manufacturing | 2024 |
| Distillery Court Development Management Company Limited | Extraterritorial | 2006 |
| Distillery Mews Management Company Limited | Households | 2005 |
| Divilment Inc. Limited | Manufacturing | 2017 |
| DJH 2020 Limited | Financial services | 1976 |
| DJM Plumbing Ltd | Construction | 2017 |
| DK Leisure Ltd | Hospitality | 2006 |
| DMC Plant Limited | Financial services | 2023 |
| DML Accountants Ltd | Professional & scientific | 2022 |
| Dmmf Services Ltd | Construction | 2021 |
| DNR Solutions (UK) Limited | Administrative & support | 2008 |
| DOC Developments Ltd | Real estate | 2023 |
| Dococ Property Developments Limited | Real estate | 2005 |
| Doherty Brennan Solicitors Limited | Professional & scientific | 2022 |
| Donaghy Bros | Wholesale & retail | 1996 |
| Dotsys Limited | Information & communication | 2011 |
| Downhill Property Company Limited | Real estate | 2009 |
| Downview Avenue Management Company Limited | Households | 2011 |
| DPL Construction & Civil Engineering (Garvagh) Limited | Construction | 2017 |
| Drain Jetters N I Ltd | Administrative & support | 2023 |
| Dram House Limited | Wholesale & retail | 2025 |
| Drambids Ltd | Wholesale & retail | 2024 |
| Drenagh Park Management Ltd | Households | 2014 |
| Drennan Consultancy Limited | Hospitality | 2024 |
| DRS Developments Limited | Construction | 1999 |
| Drum Irish Properties Ltd | Construction | 2004 |
| Drumahoe Road Residents Management Co. Ltd | Households | 2024 |
| Drumgoon Management Company Limited | Households | 2005 |
| Drumharvey Limited | Construction | 2011 |
| Drumorgan Manor Management Limited | Households | 2009 |
| Drumsaragh Farm Limited | Agriculture & fishing | 2018 |
| DRY Arch Interiors Limited | Construction | 2019 |
| Dsljm Ltd | Financial services | 2024 |
| Dtvr Security Solutions Ltd | Professional & scientific | 2020 |
| Duddy Holdings Limited | Financial services | 2015 |