| Dbmc Investments Ltd | Construction | 2014 |
| DC Auto Repair Ltd | Wholesale & retail | 2026 |
| DC Lettings (NI) Ltd | Real estate | 2015 |
| Dcentral Security 25 Limited | Administrative & support | 2025 |
| DCL Contracts Ltd | Construction | 2018 |
| DCL O'Neill Limited | Wholesale & retail | 2026 |
| DCN Civils Limited | Construction | 2019 |
| DCP (Crewe) Ltd | Real estate | 2006 |
| DDF Investments Limited | Real estate | 2025 |
| Ddjk Limited | Professional & scientific | 2022 |
| DE Equestrian Services Ltd | Arts & recreation | 2019 |
| Dealer Control Hub Ltd | Information & communication | 2026 |
| Dean Beagan Ltd | Wholesale & retail | 2023 |
| Deanfield Properties Limited | Real estate | 1983 |
| Deanmont Company Limited | Hospitality | 2023 |
| Debt Resolved Limited | Professional & scientific | 2018 |
| Declan Mckeever Financial Services Ltd | Financial services | 2024 |
| Deco Contracts Ltd | Construction | 2024 |
| Dee.Ie Ltd | Information & communication | 2007 |
| Deery Enterprises Limited | Wholesale & retail | 2025 |
| Deery Solutions Ltd | Information & communication | 2023 |
| Deirdre Mcreynolds & Co Ltd | Financial services | 2011 |
| Delacroix (Derry) Ltd | Hospitality | 2014 |
| Dellmont Developments Limited | Construction | 2008 |
| Delly Holding Limited | Wholesale & retail | 2024 |
| Deluxe Irish Golf Ltd | Extraterritorial | 2024 |
| Deluxe Irish Tours and Transfers Ltd | Administrative & support | 2024 |
| Delward Limited | Hospitality | 2013 |
| Demshor Contracts Ltd | Manufacturing | 2023 |
| DEN Management Limited | Financial services | 2013 |
| Dencro Contracts Limited | Construction | 2010 |
| Dennpat Developments Ltd | Construction | 2000 |
| Deons Mega Deals Ltd | Wholesale & retail | 2023 |
| Dermatek Inc | | 1994 |
| Dermot.Dc.Safety Ltd | Administrative & support | 2025 |
| Derry City Brewing Company Ltd | Manufacturing | 2026 |
| Derry City BUS Tours Ltd | Transport & logistics | 2024 |
| Derry City Tours Ltd | Administrative & support | 2013 |
| Derry Craft Distillery Limited | Hospitality | 2015 |
| Derry Digital Creations Ltd | Wholesale & retail | 2026 |
| Derry Hostel & Guest Accommodation Ltd | Hospitality | 2017 |
| Derry MOR Events Ltd | Arts & recreation | 2014 |
| Derry Nails & Spa Ltd | Other services | 2023 |
| Derry Phones Limited | Wholesale & retail | 2026 |
| Derry Print Workshop Ltd | Arts & recreation | 2002 |
| Derry Samaritans | Health & social care | 2016 |
| Derry Taxi's Limited | Real estate | 2001 |
| Derry Theatre Trust | Arts & recreation | 1996 |
| Derrychrier Retail Limited | Wholesale & retail | 2024 |
| Derrychrier Services Limited | Wholesale & retail | 2019 |
| Derrygirl.Ie Ltd | Information & communication | 2020 |
| DES Reid & Co Limited | Professional & scientific | 2025 |
| Desert Construction Limited | Construction | 2017 |
| Destined Ltd | Administrative & support | 2002 |
| Deveire UK Limited | Information & communication | 2019 |
| Developing Healthy Communities (DHC) Limited | Health & social care | 2016 |
| Devera Properties Limited | Real estate | 2013 |
| Devine Ebrington Limited | Hospitality | 2026 |
| Devine Moments Ltd | Professional & scientific | 2020 |
| DG Skye Limited | Arts & recreation | 2012 |
| DHG Belfast Limited | Hospitality | 2014 |
| DHG Brunswick Limited | Hospitality | 2016 |
| DHG Derry Commercial Limited | Hospitality | 2014 |
| DHG Derry Limited | Hospitality | 2014 |
| DI Bartolo Ltd | Wholesale & retail | 2024 |
| Diamond Packaging Limited | Manufacturing | 2019 |
| Diamond Simms Investments Ltd | Real estate | 2019 |
| Dian Research Ltd | Professional & scientific | 2023 |
| Diana Mclaughlin Limited | Professional & scientific | 2025 |
| Diarmuid Duffy Limited | Financial services | 2019 |
| Dida Properties Limited | Real estate | 2017 |
| Diesel Tech Ltd | Wholesale & retail | 2025 |
| Diez Atater Ltd | Wholesale & retail | 2023 |
| Different Class Clothing Limited | Wholesale & retail | 2014 |
| Different Class Hire Limited | Administrative & support | 2019 |
| Digdawg Ltd | Wholesale & retail | 2024 |
| Dillon Property Limited | Real estate | 2015 |
| Dimwood Studios Ltd | Manufacturing | 2026 |
| Dingley & Ferris Group Ltd | Real estate | 2025 |
| Direct Electrical Services (Ireland) Ltd | Construction | 1998 |
| Discount Tyre Centre NW Ltd | Wholesale & retail | 2023 |
| Disten Property Maintenance Ltd | Construction | 2003 |
| Djcp Construction Limited | Construction | 2021 |
| DJM Contractors Ltd | Construction | 2019 |
| DM Solutions Ireland Limited | Construction | 2025 |
| DM Training Solutions (N.I) Ltd | Administrative & support | 2021 |
| Dmac Consulting Engineers Ltd | Professional & scientific | 2018 |
| Dmack Data Solutions Ltd | Professional & scientific | 2025 |
| Dmccr Limited | Construction | 2013 |
| DME Building & Maintenance Limited | Construction | 2018 |
| DMG Building Ltd | Construction | 2023 |
| DMG Global-Tec NI Ltd. | Construction | 2016 |
| DMG Groundworks Contracting N.I. Limited | Other services | 2019 |
| DMG Joinery Ltd | Construction | 2026 |
| DMH Digital Holdings Limited | Financial services | 2025 |
| Dmjf Human Capital Ltd | Professional & scientific | 2024 |
| DOC Drylining Limited | Construction | 2011 |
| DOD Services Limited | Construction | 2025 |
| Dogs Bollox Apparel Ltd | Wholesale & retail | 2018 |
| Dohertys Digital Products Ltd | Information & communication | 2025 |