| Creative Joyful Moments Ltd | Wholesale & retail | 2025 |
| Crestech Ltd | Information & communication | 2026 |
| Crossfit Livin Ltd | Arts & recreation | 2021 |
| Crumlin Road Management Company Limited | Households | 2008 |
| Crush Cocktails Ltd | Wholesale & retail | 2024 |
| CS Maintenance Services Ltd | Construction | 2024 |
| Cultra View Management Ltd | Households | 2011 |
| Curl UP + DYE Belfast Ltd | Other services | 2023 |
| Custom Laser NI Limited | Extraterritorial | 2020 |
| CYA Consultancy Limited | Professional & scientific | 2023 |
| Cyanotype Media Ltd | Professional & scientific | 2024 |
| Cyberdyne Projects Ltd | Professional & scientific | 2024 |
| Cybernia Ltd | Information & communication | 2024 |
| D J Holmes Developments Ltd | Construction | 2010 |
| D Lynn Engineering Ltd | Construction | 2023 |
| D X Properties Ltd | Real estate | 2023 |
| D&P Enterprises Limited | Financial services | 2019 |
| D.R. Mitchell Holdings Ltd | Extraterritorial | 1996 |
| D.R. Mitchell Ltd. | Construction | 1990 |
| D2 Scaffolding Ltd | Construction | 2018 |
| DAB Aero Ltd | Manufacturing | 2013 |
| Daily Hot Deal Ltd | Wholesale & retail | 2025 |
| Damp Mould and Woodworm Specialists Ltd | Professional & scientific | 2025 |
| Dark Matter Productions Limited | Information & communication | 2022 |
| David Martin and SON Limited | Manufacturing | 2008 |
| Dawsy & Armin Engineering Ltd | Manufacturing | 2019 |
| Day Spa Online Ltd | Other services | 2023 |
| DC Floors Limited | Wholesale & retail | 2015 |
| DC Propco Limited | Real estate | 2023 |
| DC Retail Limited | Hospitality | 2015 |
| DCG Publications Ltd | Information & communication | 2004 |
| Decky Boyle Training Ltd | Health & social care | 2026 |
| DEL Fulton Contractors Ltd | Manufacturing | 2017 |
| Delivered Worldwide Ltd | Wholesale & retail | 2025 |
| Denso Aviation Ltd | Manufacturing | 2014 |
| DFK Aviation Ltd | Manufacturing | 2016 |
| Diane Emma Paul Ltd | Hospitality | 2003 |
| Dillon and Dodds Ltd | Hospitality | 2018 |
| Dillon's Foods Ltd | Hospitality | 2025 |
| Discerno Ltd | Information & communication | 2025 |
| Disputes Resolution Partnership Limited | Professional & scientific | 2024 |
| Ditad Limited | Health & social care | 2016 |
| Divine Mercy Private Limited | Hospitality | 2026 |
| Dmcadata Ltd | Information & communication | 2025 |
| DML Construction Ltd | Construction | 2009 |
| DMN Billposting Services Ltd | Other services | 2023 |
| DMT HQ Limited | Wholesale & retail | 2018 |
| Dolphin Court Management Limited | Extraterritorial | 1998 |
| DON Key Enterprises Ltd | Real estate | 2025 |
| Dorset Investments Limited | Hospitality | 2000 |
| Doubleaacateringsolutions Ltd | Hospitality | 2025 |
| Doxa Collection Ltd | Professional & scientific | 2019 |
| DR B Tutoring Ltd | Education | 2020 |
| Driver Training N.I. Ltd | Education | 2014 |
| Drivewayrestore NI Ltd | Administrative & support | 2024 |
| Drummond Manor Management Company Limited | Households | 2004 |
| Drumnagoon Meadow Management Company Limited | Households | 2014 |
| Drumnagoon Park Management Company Limited | Real estate | 2021 |
| Drvn Coaching Club CIC | Arts & recreation | 2026 |
| DTG Electrical Ltd | Construction | 2025 |
| Dual Glazing NI Limited | Manufacturing | 2026 |
| Dundrum Bay View Management Company Limited | Households | 2008 |
| Dundy Ltd | Manufacturing | 2025 |
| Dundyni Ltd | Wholesale & retail | 2025 |
| Duranay Barber Co Ltd | Other services | 2026 |
| DWM Engineering Ltd | Manufacturing | 2018 |
| DWW Project Management Services Ltd | Information & communication | 2015 |
| DY5ENTERPRISES Ltd | Professional & scientific | 2025 |
| Dynamic Fire NI Limited | Professional & scientific | 2019 |
| Dynamo Social Enterprises Ltd | Education | 2014 |
| East Antrim Chimney Sweep Ltd | Administrative & support | 2026 |
| East Antrim Readymix Ltd | Manufacturing | 2024 |
| Eastcoastaviation Ltd | Manufacturing | 2024 |
| Easton Developments Management Company Limited | Households | 2006 |
| Ecobia Ltd | Water & waste | 2024 |
| Ecoheat N.I. Ltd | Construction | 2023 |
| Eden Car Sales Limited | Wholesale & retail | 2022 |
| Edenderry Lofts Management Company Limited | Extraterritorial | 2008 |
| Edenmore Court Apartments Management Company Limited | Real estate | 2012 |
| EDM Solutions Ltd | Construction | 2019 |
| Edmonstone House Management Company Limited | Households | 2001 |
| Edwards Marine Ltd | Manufacturing | 2020 |
| Efra Care Services Ltd | Health & social care | 2026 |
| Egnite Consultancy Limited | Professional & scientific | 2025 |
| Ekwiti Ltd | Professional & scientific | 2017 |
| Elecc Ltd | Construction | 2023 |
| Eliana Private Limited | Transport & logistics | 2025 |
| Elite Cleaning Services (Carpets & Upholstery) Cleaning Ltd | Administrative & support | 2025 |
| Elite Hire (Antrim) Ltd | Administrative & support | 2021 |
| Ellie's Play Village Ltd | Health & social care | 2025 |
| Emailgain Limited | Manufacturing | 2025 |
| Embrace Style N.I. Ltd | Other services | 2023 |
| Emerald Computers Limited | Wholesale & retail | 2020 |
| Emergency Fire & Safety Ltd | Professional & scientific | 2011 |
| Empatech Ltd | Information & communication | 2019 |
| Encounter Jesus Ministries | Other services | 2025 |
| Energy Motion Limited | Wholesale & retail | 2023 |
| Enhanced Hair Creations Limited | Other services | 2020 |
| Epic Love Photography Ltd | Information & communication | 2012 |
| Epoxy ROX Ltd | Construction | 2022 |