| Annadale Village Management Limited | Extraterritorial | 2000 |
| Annagh Meadows Management Limited | Extraterritorial | 2005 |
| Annahaia Consultancy Limited | Professional & scientific | 2021 |
| Annahaia Properties Limited | Real estate | 2021 |
| Annalara Wine Merchants Limited | Wholesale & retail | 2021 |
| Annanpat Limited | Real estate | 2001 |
| Annavale House Management Company Limited | Households | 2001 |
| Anne Elizabeth Wood Ltd | Wholesale & retail | 2025 |
| Anne Mcmurray Development Ltd | Administrative & support | 2001 |
| Annertech (UK) Limited | Information & communication | 2021 |
| Annesley Holdings Ltd | Health & social care | 2020 |
| Annie Donaghy Ltd | Wholesale & retail | 2023 |
| Annie's Home Bakery Ltd | Manufacturing | 2015 |
| Annital Ltd | Wholesale & retail | 2021 |
| Anno Properties Limited | Real estate | 2022 |
| ANNS11 Limited | Financial services | 2018 |
| Annsfield Limited | Professional & scientific | 2006 |
| Annsgate Limited | Extraterritorial | 1998 |
| Anonymous Entertainments Limited | Arts & recreation | 2022 |
| Another Opinion Ltd | Professional & scientific | 2025 |
| Another World Belfast C.I.C. | Wholesale & retail | 2019 |
| Anova Financial Services Limited | Information & communication | 2024 |
| ANR Belfast Ltd | Hospitality | 2021 |
| ANR Core Ltd | Wholesale & retail | 2025 |
| Ansel Bing Ltd | Wholesale & retail | 2024 |
| Anst Holdings Ltd | Real estate | 2021 |
| Antares Marine Offshore Limited | Professional & scientific | 2019 |
| Antelope Transport Limited | Transport & logistics | 2015 |
| Antenna Systems Design & Installation Ltd | Extraterritorial | 2020 |
| Antenna Systems Ltd | Administrative & support | 2007 |
| Antennaware Limited | Manufacturing | 2020 |
| Anthaeum Limited | Health & social care | 2020 |
| Anthology Holdings 3 Ltd | Hospitality | 2024 |
| Anthology N.I. Limited | Hospitality | 2009 |
| Anthology Property 3 Ltd | Real estate | 2026 |
| Anthology Trading 3 Ltd | Hospitality | 2024 |
| Anthony LIU Limited | Wholesale & retail | 2024 |
| Anthony Mchugh Limited | Professional & scientific | 2024 |
| Anthony Norman Carson Ltd | Wholesale & retail | 2024 |
| Anthony Reddy Associates (NI) Limited | Professional & scientific | 2003 |
| Anthurium DEV Ltd | Information & communication | 2024 |
| Anti-Hero Films Ltd | Information & communication | 2011 |
| Antigenera Ltd | Professional & scientific | 2026 |
| Antipasto Ltd | Wholesale & retail | 2024 |
| Antons Gerria Limited | Wholesale & retail | 2025 |
| Antrim Apartment Management Limited | Real estate | 1999 |
| Antrim Asphalt Limited | Construction | 1975 |
| Antrim E CIG Limited | Wholesale & retail | 2017 |
| Antrim Electrical & Mechanical Engineers Limited | Construction | 1995 |
| Antrim Feeds Limited | Extraterritorial | 1964 |
| Antrim Massage Ltd | Health & social care | 2020 |
| Antrim Road Apartments Management Co. Ltd | Extraterritorial | 2007 |
| Antrim Road Autos Limited | Wholesale & retail | 2023 |
| Antrim Shipbrokers (NI) Limited | Transport & logistics | 2014 |
| Antrim Warehousing and Distribution Services Limited | Other services | 1973 |
| Antrim Wind Energy Ltd | Energy | 2006 |
| Anugrah Sarl Ltd | Wholesale & retail | 2025 |
| Anvari Partners Ltd | Real estate | 2013 |
| Anwoth Ltd | Real estate | 2017 |
| Anytime Login Ltd | Information & communication | 2016 |
| AOA Traders Ltd | Real estate | 2025 |
| AOB Advisory Limited | Professional & scientific | 2016 |
| AOB Nutrition Ltd | Wholesale & retail | 2021 |
| Aoife Devlin Architects Limited | Professional & scientific | 2024 |
| AOM Ltd | Information & communication | 2013 |
| AON Decs Limited | Construction | 2019 |
| Aonghusa Ventures Ltd. | Professional & scientific | 2011 |
| Aoni Hong Kong International Co Limited | Wholesale & retail | 2026 |
| Aorta Business Solutions NI Limited | Information & communication | 2015 |
| AP Eventss NI Limited | Other services | 2021 |
| AP Holdings (N.I.) Limited | Real estate | 2016 |
| AP MOS Ltd | Health & social care | 2024 |
| AP TEC Engineering Limited | Professional & scientific | 2022 |
| Apace EZ Solutions Limited | Wholesale & retail | 2025 |
| Apache Boxing Limited | Arts & recreation | 2024 |
| Apachetribebelfast Ltd | Wholesale & retail | 2024 |
| Apamore Services Ltd | Construction | 2012 |
| Apartment 39 the Courtyard Limited | Real estate | 2019 |
| Apartments NOW Ltd | Real estate | 2017 |
| Apateon Limited | Wholesale & retail | 2026 |
| APD N.I Ltd | Administrative & support | 2017 |
| Apek Investments Limited | Financial services | 2018 |
| Apex Auto Sales Belfast Ltd | Wholesale & retail | 2026 |
| Apex Consulting Group Services Ltd | Professional & scientific | 2024 |
| Apex Consulting Services Ltd | Professional & scientific | 2026 |
| Apex Driver Training Ltd | Education | 2017 |
| Apex Fintech Solutions UK Ltd | Information & communication | 2019 |
| Apex Group Training Ltd | Administrative & support | 2025 |
| Apex Holdings Belfast Limited | Financial services | 2023 |
| Apex Medical Solutions Ltd | Health & social care | 2024 |
| Apex Physiotherapy Ltd | Other services | 2004 |
| Apex Physique Ltd | Wholesale & retail | 2026 |
| Apex Pictures Ltd | Information & communication | 2012 |
| Apex Trade Group Ltd | Wholesale & retail | 2026 |
| Apheideo Associates Ltd | Health & social care | 2014 |
| Apiary Court Management Company Limited | Households | 2004 |
| Apjm Trading Ltd | Information & communication | 2017 |
| Apliance Store Ltd | Wholesale & retail | 2023 |
| Apogee Enhancements (NI) Limited | Real estate | 2022 |
| Apollo Blasting Ltd | Manufacturing | 2023 |