| Dashin' Hounds Limited | Other services | 2020 |
| Dason Medical Limited | Health & social care | 2025 |
| Dassah Revive Ltd | Wholesale & retail | 2026 |
| Data Direct Limited | Information & communication | 2025 |
| Data Driven Healthcare Ltd | Information & communication | 2024 |
| Data Forensics Ltd | Information & communication | 2020 |
| Data Intellect Services Limited | Information & communication | 2011 |
| Datapac (N.I.) | Information & communication | 1998 |
| Dataworks Management Company Limited | Real estate | 2022 |
| Datinvest Ltd | Financial services | 2022 |
| Datza Limited | Professional & scientific | 1999 |
| Davant Ltd | Real estate | 2024 |
| Davcrow Limited | Real estate | 2010 |
| Dave and Danny Ltd | Wholesale & retail | 2024 |
| Dave Early Connection Limited | Administrative & support | 2001 |
| Dave K Limited | Information & communication | 2023 |
| Davencroft Europe Limited | Manufacturing | 2021 |
| Davenport Contracts Ltd | Construction | 2026 |
| Davenport House (NI) Limited | Information & communication | 2022 |
| Davenport Motors Ltd | Wholesale & retail | 2026 |
| Davenport Overseas Logistics LP | | 2018 |
| Davey Strategic Advisory Ltd | Professional & scientific | 2026 |
| Davi-Goodfrey Ltd | Wholesale & retail | 2025 |
| Davianmira Limited | Health & social care | 2025 |
| David Adams Ltd | Wholesale & retail | 2025 |
| David Andrews Wedding Cars Ltd | Administrative & support | 2023 |
| David Armstrong Consulting Ltd | Professional & scientific | 2025 |
| David Crymble & Sons Ltd | Other services | 2016 |
| David Cuttle Limited | Agriculture & fishing | 1991 |
| David Dickson Ltd | Wholesale & retail | 2023 |
| David Gill Engineering Ltd | Manufacturing | 2019 |
| David Graham Consultancy Limited | Professional & scientific | 2023 |
| David Graham Fitness Ltd | Other services | 2011 |
| David Hammill Plastering Ltd | Construction | 2023 |
| David Hanna Fitness Belfast Ltd | Other services | 2017 |
| David Henderson Design Ltd | Information & communication | 2014 |
| David Hughes Rental Limited | Real estate | 2018 |
| David James Anderson Ltd | Wholesale & retail | 2024 |
| David James Ball Ltd | Wholesale & retail | 2025 |
| David James Clarke Limited | Wholesale & retail | 2025 |
| David James Ward Ltd | Wholesale & retail | 2025 |
| David John Mitchell Ltd | Wholesale & retail | 2025 |
| David Kealey Ltd | Health & social care | 2011 |
| David Kennedy Recruitment Ltd. | Administrative & support | 2019 |
| David Lynas Consulting Limited | Information & communication | 2012 |
| David MAH Ltd | Wholesale & retail | 2024 |
| David Mccaughey Dental Practice Limited | Health & social care | 2004 |
| David Mcclean Limited | Professional & scientific | 2012 |
| David Mcclurkin Ltd | Wholesale & retail | 2025 |
| David Mccormack Clinical Psychology Services Limited | Health & social care | 2026 |
| David Mccrory Ltd | Health & social care | 2002 |
| David Mcgowan Limited | Construction | 2021 |
| David Mcnamee M.S. Ltd | Health & social care | 2010 |
| David Murphy Towing Brackets Limited | Manufacturing | 1979 |
| David Neely Ltd | Health & social care | 2021 |
| David O'Doherty Surveyors Limited | Professional & scientific | 2013 |
| David Paul Cross Foundation Limited | Education | 2018 |
| David Porter (N.I.) Ltd | Professional & scientific | 2019 |
| David Porter Trading Ltd | Wholesale & retail | 2025 |
| David Scott (Agencies) Limited | Wholesale & retail | 1986 |
| David Walker Music Limited | Arts & recreation | 2022 |
| Davidson & Boyd Developments Limited | Real estate | 2004 |
| Davidson & Hardy Limited | Extraterritorial | 2022 |
| Davidson Online Training (DOT) Limited | Administrative & support | 2021 |
| Davidson Walker Ltd | Hospitality | 2019 |
| Davinci Photovoltaic Limited | Energy | 2020 |
| Daviro Consulting Ltd | Information & communication | 2017 |
| Davis Rigging Ltd | Construction | 2025 |
| Davison & Associates (NI) Ltd | Financial services | 2009 |
| Davison Boat Limited | Wholesale & retail | 2025 |
| Davison Dalzell Property and Investments Limited | Real estate | 2025 |
| Davison Hospitality Ltd | Hospitality | 2023 |
| Davison Lamont Ltd | Financial services | 2012 |
| Davonne Housebakes Ltd | Manufacturing | 2008 |
| Davy Foster Eyewear Ltd | Wholesale & retail | 2024 |
| Dawar Traders Ltd | Wholesale & retail | 2024 |
| Dawn Shines Limited | Wholesale & retail | 2023 |
| Dawsee Media Limited | Information & communication | 2021 |
| Dawson Andrews Ltd | Information & communication | 2015 |
| Dawson Materials Handling Equipment Ltd | Wholesale & retail | 2000 |
| Dawson Street Trading Company Limited | Construction | 2024 |
| Dawson Whyte Limited | Financial services | 2003 |
| Daxcon Ltd | Other services | 2015 |
| DAY35 Limited | Real estate | 2024 |
| Dayday Lists Limited | Wholesale & retail | 2025 |
| Daymer Associates Limited | Professional & scientific | 2021 |
| Daypee Ltd | Wholesale & retail | 2025 |
| Daywalker Capital Limited | Information & communication | 2025 |
| DB Investment Holdings Limited | Financial services | 2025 |
| DB Retailing NI Limited | Wholesale & retail | 2025 |
| DB Top Co Limited | Financial services | 2025 |
| Db(Ni) Realisations Limited | Construction | 1975 |
| Dbdeguzman Ltd | Health & social care | 2023 |
| Dbfin LP | | 2020 |
| DBG Media Limited | Information & communication | 2019 |
| Dbgt 2011 (NO.3) Limited | Real estate | 2011 |
| DBJ Imaging Solutions Limited | Health & social care | 2024 |
| DBM Labs Ltd | Professional & scientific | 2025 |
| DBM Utilities Ltd | Construction | 2021 |
| DBS Enterprises Ltd | Professional & scientific | 2010 |