| Derrymore Investments Limited | Real estate | 2014 |
| Derryogue Farms Ltd | Agriculture & fishing | 2013 |
| Derryogue Holdings Limited | Extraterritorial | 2016 |
| Derryogue Property Limited | Real estate | 2016 |
| Derryogue Sand Company Ltd | Mining & quarrying | 2002 |
| Derrywilligan Farm Ltd | Agriculture & fishing | 2020 |
| DES Winter | Health & social care | 2011 |
| DES Winter Consultants Limited | Health & social care | 2011 |
| Design 777 Limited | Wholesale & retail | 2024 |
| Design a New Shed Ltd | Wholesale & retail | 2020 |
| Design Studio 40 Ltd | Professional & scientific | 2021 |
| DESIGNHOUZ33 Limited | Wholesale & retail | 2023 |
| Desiúnta Ltd | Professional & scientific | 2018 |
| Devine Skin Nurse Ltd | Health & social care | 2024 |
| Devnex Criticial Solutions Limited | Wholesale & retail | 2026 |
| Dexburg Properties L.P. | | 2017 |
| DEZ Property Holding Limited | Hospitality | 2018 |
| DF JP Group Limited | Arts & recreation | 2018 |
| Dfni Ltd | Arts & recreation | 2025 |
| DG Joinery & Construction Limited | Construction | 2024 |
| DG Professional Group Limited | Administrative & support | 2026 |
| DGD & Sons Limited | Professional & scientific | 2025 |
| Dgon (N.I.) Limited | Real estate | 2023 |
| DH NI Consultancy Ltd | Professional & scientific | 2022 |
| DHD Group Ltd | Financial services | 2021 |
| Dhmp Limited | Real estate | 2006 |
| DHS Truck Styling Ltd | Manufacturing | 2014 |
| Diadis Ltd | Wholesale & retail | 2024 |
| Dialledinbymaginn Ltd | Education | 2024 |
| Diamex Trading LP | | 2016 |
| Diamond Property Management Services Ltd | Real estate | 2019 |
| Diamond Real Estate Management Ltd | Real estate | 2025 |
| Diamonds Restaurant Ltd | Hospitality | 2004 |
| Dieci Ltd | Extraterritorial | 2010 |
| Dieci UK Ltd | Extraterritorial | 2010 |
| Digital Isle Limited | Wholesale & retail | 2014 |
| Digney Bros. Limited | Real estate | 1994 |
| Digney Grant Financial Planning Limited | Financial services | 2014 |
| Digney Transport Ltd | Transport & logistics | 2025 |
| Diner Five Ltd | Hospitality | 2024 |
| Dinsmore Construction Ltd | Construction | 2025 |
| Diocese of Dromore Trustee | Other services | 2011 |
| Directus Marketing Ltd | Professional & scientific | 2022 |
| Discovery Publications Ireland Ltd | Information & communication | 2013 |
| Discuvr Innovation Ltd | Professional & scientific | 2024 |
| Dish-Dash Ltd | Wholesale & retail | 2020 |
| Dissolved Createpro LP | | 2021 |
| Distill Direct Trading Limited | Wholesale & retail | 2023 |
| Distriview Ltd | Professional & scientific | 2025 |
| Divernagh Dairies Ltd | Agriculture & fishing | 2019 |
| Diverse Space Ltd | Education | 2023 |
| Diversiton Limited | Professional & scientific | 2004 |
| Divinelightstudio Ltd | Arts & recreation | 2025 |
| Diviney Limited | Information & communication | 2012 |
| DIVISION88 NI Ltd | Wholesale & retail | 2024 |
| Dizzyland FUN Fairs Ltd | Extraterritorial | 2011 |
| Dizzylands FUN Fairs Ltd | Extraterritorial | 2011 |
| DJ Properties (NI) Ltd | Real estate | 2014 |
| DJ3 Transport Limited | Transport & logistics | 2026 |
| DJD Contracts Ltd | Construction | 2021 |
| Djmck Property Ltd | Real estate | 2026 |
| DJR Bricklaying Ltd | Construction | 2024 |
| Djsd Construction Ltd | Construction | 2025 |
| DK Pro Hair Ltd | Other services | 2025 |
| DK Roofing Ltd | Construction | 2018 |
| DKR Construction Ltd | Construction | 2006 |
| DLD Transport Ltd | Transport & logistics | 2015 |
| Dljem Ltd | Professional & scientific | 2025 |
| DM Car & Commercials Limited | Wholesale & retail | 2017 |
| DM Construction Consultancy Limited | Professional & scientific | 2017 |
| Dmac Plastering Ltd | Construction | 2021 |
| DMB (1991) Ltd | Health & social care | 2021 |
| DMB Haulage Ltd | Transport & logistics | 2016 |
| DMB Murphy Farming Ltd | Agriculture & fishing | 2013 |
| DMC Building & Construction Ltd | Construction | 2018 |
| DMC Payroll and Consulting Ltd | Professional & scientific | 2023 |
| Dmcam Construction Limited | Professional & scientific | 2023 |
| DMD Plastering Ltd | Construction | 2024 |
| DML Logistics Limited | Transport & logistics | 2024 |
| Dmmd Investments Limited | Financial services | 2025 |
| DMT Trading Ltd | Wholesale & retail | 2026 |
| Dndlaw (2024) Limited | Professional & scientific | 2024 |
| Dndlaw Limited | Professional & scientific | 2013 |
| DNG Construction & Maintenance Ltd | Construction | 2016 |
| DNM Property Ltd | Construction | 2013 |
| DNS Electrical Contracts Ltd | Construction | 2004 |
| DO IT ALL Property Maintenance Limited | Construction | 2023 |
| DO the Deals Limited | Information & communication | 2021 |
| Docon Ltd. | Construction | 2012 |
| Document Binding Company Limited | Administrative & support | 1988 |
| Dog Eclipse Ltd | Arts & recreation | 2015 |
| DOH Softplay Ltd | Arts & recreation | 2026 |
| Doha Investments Ltd | Financial services | 2024 |
| Doherty Build Ltd | Construction | 2015 |
| Doherty Supply Chain Partners Ltd | Professional & scientific | 2025 |
| Dollard Contracts Ltd | Construction | 2024 |
| Dolo DD Ltd | Arts & recreation | 2010 |
| Domani Investments Limited | Hospitality | 2022 |
| Dombucha Limited | Wholesale & retail | 2025 |
| DON Contracts Limited | Construction | 2017 |