| Deal Mane Ltd | Agriculture & fishing | 2025 |
| Dealz Wholesale Ltd | Wholesale & retail | 2026 |
| Declan Derby Consulting Ltd | Professional & scientific | 2007 |
| Decor-Wright Paints Limited | Construction | 2000 |
| Deebrief Ltd | Information & communication | 2026 |
| Deer Park Lawns Ltd | Agriculture & fishing | 1999 |
| Deering (Phase 1 ) Management Limited | Households | 2005 |
| Deering (Phase 2) Management Ltd | Households | 2015 |
| Defined Calculus Ltd | Administrative & support | 2017 |
| Definitive Car Detail and Customs Limited | Wholesale & retail | 2025 |
| Defy the Stars Ltd | Manufacturing | 2019 |
| Degree Refrigeration & Air Conditioning Ltd | Construction | 2008 |
| Deimos Knives Ltd | Manufacturing | 2020 |
| Deirdre Lavery Solicitors Ltd | Professional & scientific | 2014 |
| Deliver ME Timber Ltd | Wholesale & retail | 2019 |
| Delta Blue Training and Consultancy Ltd | Information & communication | 2012 |
| Delta Properties (Portadown) Limited | Real estate | 2024 |
| Delta Sign Systems Ltd | Manufacturing | 2011 |
| Deluxe Art & Theme Limited | Manufacturing | 2002 |
| Demesne Court Management Company Limited | Households | 2002 |
| Dent BOY Ltd | Wholesale & retail | 2021 |
| Dent Expert Ireland Ltd | Wholesale & retail | 2025 |
| Dermot Grimley Consulting Limited | Information & communication | 2013 |
| Derrinraw Consultancy Ltd | Administrative & support | 2026 |
| Derry Group Ireland Ltd | Transport & logistics | 2020 |
| Derry Group Limited | Transport & logistics | 2024 |
| Derry Refrigerated Transport Limited | Transport & logistics | 2013 |
| Derry Transport Group Ltd | Transport & logistics | 2020 |
| Derryadd Pallets Ltd | Manufacturing | 2006 |
| Derrygavad Properties Limited | Real estate | 2023 |
| Derryhale Management Limited | Real estate | 2004 |
| Derryloiste Meadows Management Company Limited | Households | 2006 |
| Derrymore Construction Ltd | Construction | 2015 |
| Derryola Freight Limited | Transport & logistics | 2014 |
| Derrys Furniture Limited | Manufacturing | 2020 |
| Derrys Holdings Limited | Manufacturing | 2020 |
| Derrys Limited | Manufacturing | 1986 |
| Derrys Skelmersdale Limited | Real estate | 2024 |
| Derrytagh Properties Limited | Real estate | 2024 |
| Design Stics Ltd | Information & communication | 2023 |
| Designs Refined Ltd | Professional & scientific | 2024 |
| Designshop Solutions Limited | Construction | 2010 |
| Desy Cleaning and Handy Services Limited | Administrative & support | 2025 |
| Detrosz Ltd | Transport & logistics | 2022 |
| Devcon Homes Ltd | Construction | 2018 |
| Devibi Ltd | Information & communication | 2025 |
| Device Advice Ltd | Professional & scientific | 2023 |
| Devpack Limited | Wholesale & retail | 2026 |
| DFM Properties Limited | Real estate | 2005 |
| Dfwz Ltd | Wholesale & retail | 2020 |
| DGB Contracts Ltd | Construction | 2023 |
| DGH Recovery Ltd | Transport & logistics | 2016 |
| DH CAM Services Ltd | Professional & scientific | 2026 |
| Diamond Nails & Spa Portadown Limited | Other services | 2026 |
| Diamond Stella Ltd | Other services | 2025 |
| Diamond Valley Recruitment Limited | Administrative & support | 2022 |
| Dickson & Henderson Construction Limited | Construction | 1990 |
| DIG Attachments Ltd | Wholesale & retail | 2024 |
| Digi-Tone (NI) Ltd | Manufacturing | 2012 |
| Digiclub Ltd | Professional & scientific | 2022 |
| Digispark Reaction CIC | Education | 2025 |
| Digital Revamp NI Ltd | Information & communication | 2025 |
| Direct Rents Ltd | Real estate | 2025 |
| Disynct Limited | Information & communication | 2025 |
| Ditaisling Limited | Real estate | 2019 |
| Divers Newco Limited | Real estate | 2021 |
| Diverse Minds Events Limited | Education | 2019 |
| Divine Home Care PVT Ltd | Health & social care | 2023 |
| DJA Contractors Limited | Construction | 2022 |
| DJB Consultants (NI) Limited | Financial services | 2010 |
| DJC (NI) Limited | Construction | 2010 |
| Dlcd Property Ltd | Real estate | 2026 |
| Dlmc Solutions Ltd | Professional & scientific | 2024 |
| DM FOX Bricklaying Ltd | Construction | 2026 |
| DMC Event Promotions Limited | Arts & recreation | 2023 |
| DMC Financial Services (NI) Limited | Financial services | 2013 |
| DMC Global Consulting Ltd | Professional & scientific | 2017 |
| DMC Groundwork Contracts Ltd | Construction | 2014 |
| DMC Survey Services Ltd | Professional & scientific | 2010 |
| DMK Auto Repairs Ltd | Wholesale & retail | 2025 |
| Dmmi Marine Limited | Wholesale & retail | 2019 |
| Dmsc Ltd | Construction | 2013 |
| Dodds Estates Limited | Real estate | 2023 |
| Dodds Property Assets Limited | Real estate | 2024 |
| Doerla Ltd | Wholesale & retail | 2025 |
| Dog Life Limited | Wholesale & retail | 2025 |
| Doherty Consulting Services Ltd | Professional & scientific | 2020 |
| Dolce & Gelato Limited | Hospitality | 2011 |
| Dollingstown Football Club Limited | Arts & recreation | 2020 |
| Donard Living Limited | Real estate | 2022 |
| Doncarn Limited | Financial services | 2023 |
| Donnelly Haulage Limited | Transport & logistics | 2010 |
| Donut Ltd | Professional & scientific | 2010 |
| Dornan and Associates Ltd | Other services | 2020 |
| Double UPP Ltd | Hospitality | 2011 |
| Doudou Massage Limited | Health & social care | 2023 |
| Douglas Bleary Limited | Real estate | 2022 |
| Down Armagh Rural Transport Partnership | Transport & logistics | 2000 |
| Downshire Surveyors Ltd | Real estate | 2020 |
| DR Angel Ltd | Health & social care | 2025 |