| 104 Tennent Street Management Co. Limited | Real estate | 2022 |
| 11MILLSTREET Limited | Professional & scientific | 2026 |
| 16NEWSTREETED Limited | Professional & scientific | 2026 |
| 17 QS Management Company Ltd | Households | 2018 |
| 1859 Revival Ltd | Real estate | 2014 |
| 198 Brollagh Road Ltd | Real estate | 2021 |
| 274SYCAMORES Limited | Professional & scientific | 2026 |
| 2BSUR Limited | Professional & scientific | 2025 |
| 2M Care Service Ltd | Health & social care | 2024 |
| 3:16 Trust Limited | Hospitality | 2019 |
| 3D Eco OIL Limited | Wholesale & retail | 2015 |
| 3DK Commercials Limited | Wholesale & retail | 2026 |
| 43MEADOWS Limited | Professional & scientific | 2026 |
| 44 Head Street Management Company Limited | Real estate | 2006 |
| A Flanagan Engineering Ltd | Manufacturing | 2026 |
| A Welsh Ltd | Health & social care | 2021 |
| A&A Mulligan Properties Ltd | Real estate | 2026 |
| A&D Smart Ltd | Administrative & support | 2025 |
| A1 Commercial Holdings Ltd | Financial services | 2021 |
| A1 Commercial Repairs (NI) Ltd | Manufacturing | 2014 |
| A1 Global Logistics Ltd | Transport & logistics | 2014 |
| A1 Global Properties (NI) Ltd | Transport & logistics | 2019 |
| A1 Logistics Holdings Ltd | Financial services | 2021 |
| A1 Transport (NI) Ltd | Transport & logistics | 2009 |
| AAA Pristine Cleaning Ltd | Administrative & support | 2020 |
| Aaron Dembski-Bowden Ltd | Arts & recreation | 2025 |
| ABA Developments Ltd | Real estate | 2024 |
| Abdel Electrical Co. Limited | | 1987 |
| ABQ Power Services Ltd | Construction | 2010 |
| Absoco Limited | Transport & logistics | 2019 |
| Access Avenue International Limited | Health & social care | 2025 |
| Access Rescue Consulting at Height Ltd | Professional & scientific | 2014 |
| Accessible Adventures Ireland CIC | Education | 2025 |
| Acel Energy NI Limited | Professional & scientific | 2023 |
| Acos (N.I.) Holdings Limited | Information & communication | 2021 |
| Acos (N.I.) Limited | Information & communication | 1991 |
| ACS Claims Limited | Financial services | 2016 |
| ACS Events Limited | Hospitality | 2024 |
| ACTIV8 Events Belfast Ltd | Arts & recreation | 2026 |
| Actpsych Marketing Limited | Professional & scientific | 2019 |
| Advanced Cleaning Experts Limited | Administrative & support | 2016 |
| Aesculus Consulting Ltd | Professional & scientific | 2020 |
| Affinitas Information Technology Limited | Information & communication | 2021 |
| Affluentsuccess Ltd | Professional & scientific | 2024 |
| AG International Transport Ltd | Transport & logistics | 2023 |
| AG Property Solutions NI Ltd | Real estate | 2025 |
| Aghalane Contracts Limited | Construction | 2017 |
| Agharainey Court Management Company Limited | Administrative & support | 2004 |
| Aghindaiagh Wind Limited | Energy | 2012 |
| Aghinver Boat Co. Limited | Arts & recreation | 1973 |
| Aghyoule Eggs Limited | Wholesale & retail | 2025 |
| AGR Precision Engineering Limited | Professional & scientific | 2023 |
| Agricultural Consultancy Ltd | Professional & scientific | 2023 |
| Agridirect UK Limited | Wholesale & retail | 2017 |
| Agrilink Farm Services NI Limited | Manufacturing | 2023 |
| AHH Limited | Professional & scientific | 2017 |
| AIM Estates Limited | Real estate | 2007 |
| Air Tightness and Building Energy Consultants Ltd. | Construction | 2010 |
| Airfield Properties Limited | Real estate | 2001 |
| Aisling Centre Company Ltd | Health & social care | 1992 |
| AJT Consult Limited | Extraterritorial | 2023 |
| AKO Kurdish Barber Ltd | Other services | 2026 |
| Alan Cathcart Limited | Administrative & support | 2016 |
| Alan Graham Recovery Ltd | Wholesale & retail | 2025 |
| Alan Mccormick Haulage Ltd | Transport & logistics | 2021 |
| Aleron Properties Limited | Real estate | 2005 |
| Alex Knowles Structural Design Ltd | Professional & scientific | 2025 |
| Alexandra & Horatiu Ltd | Health & social care | 2024 |
| Alexandra Terrace Residents Management Company Ltd | Households | 2015 |
| Alignni Ltd | Other services | 2025 |
| Aligra Ltd | Wholesale & retail | 2024 |
| ALJ Investments Ltd | Real estate | 2022 |
| ALL Physio Ltd | Health & social care | 2024 |
| Allan Curran Architects Limited | Professional & scientific | 2004 |
| Alpha 7 Inc Limited | Health & social care | 2025 |
| Alpine Properties Limited | Real estate | 1999 |
| Alpvenagh Limited | Agriculture & fishing | 2015 |
| Altdrumman Limited | Real estate | 2022 |
| Am:Pm Communications Ltd | Professional & scientific | 2008 |
| Aman Association | Education | 2020 |
| AMD Renewables Ltd | Professional & scientific | 2025 |
| AMF Mech Ltd | Professional & scientific | 2021 |
| AML Plant Ltd | Wholesale & retail | 2017 |
| AMP Sync Ltd | Information & communication | 2026 |
| Anchorage Developments Limited | Construction | 2004 |
| Andrew Mahon Properties Limited | Real estate | 1996 |
| Anfield Iron Ltd | Hospitality | 2023 |
| Angie's New Haven Apizza Limited | Hospitality | 2026 |
| ANN Street Dental Practice Limited | Health & social care | 2011 |
| Annagh Social Farm CIC | Health & social care | 2016 |
| Annan Interiors Limited | Wholesale & retail | 1999 |
| Antoinette Toya Ltd | Wholesale & retail | 2023 |
| Aona Environmental Consulting (UK) Ltd | Professional & scientific | 2019 |
| APG Agri Ltd | Wholesale & retail | 2019 |
| APK Stonework Ltd | Manufacturing | 2022 |
| Apollo Fulfilment Ltd | Wholesale & retail | 2013 |
| Apollo Solar Ltd | Energy | 2025 |
| Apostolic Fellowship NI Limited | Other services | 2024 |
| Archgrove Homes Limited | Construction | 2022 |
| ARD Bhearna Limited | Financial services | 2023 |