| Coyle Developments Limited | Construction | 2019 |
| Coyle Group Limited | Construction | 2019 |
| Coyle Holdings Limited | Extraterritorial | 2009 |
| CPD Homes LLP | | 2018 |
| Crafty Little Linguists Ltd | Education | 2024 |
| Craig Estates | Extraterritorial | 1999 |
| Crane Operator Assurance Ltd | Education | 2024 |
| Creative West Ltd | Information & communication | 2017 |
| Creighton Ward Productions Ltd | Administrative & support | 2017 |
| Crest Upholstery Ltd | Manufacturing | 2025 |
| Crossfit Avenge Limited | Arts & recreation | 2018 |
| Crown Solar & Storage Ltd | Wholesale & retail | 2026 |
| Cryo MOD Ltd | Extraterritorial | 2023 |
| CSR Ground Rent Services Ltd | Real estate | 2023 |
| CSR Online Trading Limited | Wholesale & retail | 2023 |
| CSV & Data Integrity Services Ltd | Information & communication | 2020 |
| CTH Imaging Limited | Health & social care | 2021 |
| Cuatro Property Ltd | Real estate | 2023 |
| Cubic Asset Management Ltd | Real estate | 2025 |
| Cummings O'Neill Limited | Arts & recreation | 2016 |
| CW Agri Limited | Wholesale & retail | 2025 |
| CW Electrical Services & Design Ltd | Construction | 2018 |
| CY Mechanical Design Solutions Limited | Professional & scientific | 2024 |
| Cyberprint Ltd | Manufacturing | 2024 |
| Cyntax Software Ltd | Information & communication | 2019 |
| D & G Tyre Bay Ltd | Wholesale & retail | 2013 |
| D J Simpson Properties Limited | Households | 2023 |
| D M Developments (2018) Ltd | Construction | 2018 |
| D&T Business Consultants Ltd | Professional & scientific | 2010 |
| D.T. Mcallister & Associates Ltd | Wholesale & retail | 2020 |
| D.Wilson Healthcare Ltd | Health & social care | 2023 |
| DA Pizza Plus Ltd | Hospitality | 2022 |
| Dagda Properties Limited | Real estate | 2019 |
| Dale's Race Tuning Ltd | Manufacturing | 2025 |
| Dalzell Property and Facilities Management Ltd | Administrative & support | 2016 |
| Danetal Commerce Ltd | Wholesale & retail | 2023 |
| Danetal Holdings Ltd | Financial services | 2022 |
| Dargan Press Limited - the | Manufacturing | 1986 |
| Darran Anderson H&S Consulting Ltd | Professional & scientific | 2025 |
| Dawg House Productions Ltd | Information & communication | 2026 |
| DC Properties (Belfast) Ltd | Real estate | 2024 |
| DC Tattoos Ltd | Arts & recreation | 2018 |
| DDC Plumbing & Mechanical Ltd | Construction | 2023 |
| DDC UK Promotions Ltd | Hospitality | 2025 |
| Dean Best Automotive Ltd | Wholesale & retail | 2021 |
| Debbie Morrow People Solutions Ltd | Professional & scientific | 2024 |
| Decor Interiors Ltd | Wholesale & retail | 2018 |
| Decrown Global Concept Limited | Wholesale & retail | 2024 |
| Deliver IT - IT Consultancy Services Ltd | Information & communication | 2017 |
| Delta Security Systems (N.I.) Ltd | Information & communication | 2017 |
| Denver Leigh Interiors Limited | Professional & scientific | 2023 |
| Dermotmurphydigital Limited | Professional & scientific | 2019 |
| Derrymorgan Distribution Ltd | Transport & logistics | 2012 |
| Dewberry Portraits Ltd | Professional & scientific | 2023 |
| DGS Logistics Limited | Transport & logistics | 1994 |
| Diamond Homes (NI) Ltd | Construction | 2010 |
| Diamond Nails & Spa Abbey Ltd | Other services | 2026 |
| Diamond Nails Abbey Centre Ltd | Other services | 2024 |
| Diamond Trucks Limited | Manufacturing | 2014 |
| Digital Guardian Angel | Education | 2017 |
| Digital Pulse Works Ltd | Wholesale & retail | 2025 |
| Dine at Luna Limited | Hospitality | 2025 |
| Direct Deliveries (NI) Limited | Transport & logistics | 2011 |
| Diskshred Ltd | Extraterritorial | 2009 |
| Djjintensity Ltd | Public administration | 2022 |
| DK Joinery & Sheds Ltd | Manufacturing | 2024 |
| DLM Trading AS Claim Solutions Limited | Financial services | 2024 |
| DLR Leisure Ltd | Arts & recreation | 2005 |
| DMA Boarders Ltd | Construction | 2022 |
| Dmpd Ltd | Hospitality | 2022 |
| DN Beauty Limited | Other services | 2025 |
| Dog Days Limited | Arts & recreation | 2016 |
| Doire Beag Management Company Limited | Real estate | 2001 |
| Donganies Automations Limited | Transport & logistics | 2023 |
| Donna Louise Mcmullan Ltd | Extraterritorial | 2022 |
| DOT Micro Scalp Revive Ltd | Health & social care | 2024 |
| DOT Micro Training Academy Ltd | Education | 2024 |
| DR & MC Investments Limited | Professional & scientific | 2019 |
| DR Heating Ltd | Construction | 2009 |
| Dramallama Ltd | Information & communication | 2021 |
| Dream Maker Competitions Ltd | Information & communication | 2023 |
| Dream Media Ireland Ltd | Information & communication | 2013 |
| Drmr Property LLP | | 2025 |
| Drumbo Investments Limited | Professional & scientific | 2020 |
| DS Bookkeeping Services Ltd | Professional & scientific | 2016 |
| Dsib Investing Limited | Real estate | 2024 |
| Dudes & Divas the Village C.I.C. | Education | 2026 |
| Dunadry Hotel Ltd | Hospitality | 2017 |
| Dundee Dental Laboratory Ltd | Manufacturing | 2023 |
| Dune (Investments) Limited | Real estate | 2016 |
| Dunluskin Ltd | Hospitality | 2017 |
| Dunsilly Hotel Ltd | Hospitality | 2003 |
| Dunsuivnish Ltd | Real estate | 2022 |
| Dylan & Arthur Co. Ltd | Wholesale & retail | 2025 |
| Dynamic Fire and Security Limited | Manufacturing | 2016 |
| E & C Inns Ltd | Hospitality | 2001 |
| E.J.C. Contracts Ltd | Construction | 2003 |
| Eagle EYE Drone Photography Ltd | Professional & scientific | 2025 |
| Eagle Holdings Ireland Limited | Professional & scientific | 2005 |
| Earlford 1961 Limited | Extraterritorial | 2013 |