| AN Post (NI) Limited | Financial services | 1991 |
| AN Puca Limited | Real estate | 2007 |
| AN Tsnathaid Mhor Teoranta | Arts & recreation | 2004 |
| Anaclasis Limited | Wholesale & retail | 2026 |
| Anaecon Ltd | Health & social care | 2013 |
| Anaeko Limited | Information & communication | 2002 |
| Analytical Logic Ltd | Information & communication | 2010 |
| Analytics Engines Limited | Information & communication | 2008 |
| Anam Collective Ltd | Agriculture & fishing | 2020 |
| Anam Records LLP | | 2025 |
| Anann's Arch Ltd | Arts & recreation | 2020 |
| Anatomy Trains (UK & Europe) Limited | Education | 2008 |
| Anbrox Ltd | Professional & scientific | 2024 |
| Anchor Data Systems (N.I.) Limited | Wholesale & retail | 1995 |
| Anchor Speech Therapy Limited | Health & social care | 2025 |
| Anchor Watch Management Company Limited | Households | 2005 |
| Anchorage Inn Holding Limited | Hospitality | 2026 |
| Anchorage Inn Property Limited | Real estate | 2026 |
| Anchorage Inn Trade Limited | Hospitality | 2026 |
| Ancor Care Limited | Health & social care | 2023 |
| Andar Daew Ltd | Wholesale & retail | 2024 |
| Anders Florence Ltd | Administrative & support | 2019 |
| Anderson & Macaulay Mortgage Services LLP | | 2007 |
| Anderson Advertising Limited | Professional & scientific | 2000 |
| Anderson Crosshill Limited | Construction | 2024 |
| Anderson Electrical Services (NI) Ltd | Construction | 2025 |
| Anderson Estates (NI) Ltd | Real estate | 2005 |
| Anderson Heating Services Ltd | Construction | 2025 |
| Anderson Mechanical Limited | Construction | 2018 |
| Anderson Medical Limited | Health & social care | 2021 |
| Anderson Mental Health Limited | Health & social care | 2016 |
| Anderson Spratt Group Holdings Limited | Professional & scientific | 1982 |
| Anderson Spratt Group Limited | Professional & scientific | 1992 |
| Anderton 1 Ltd | Wholesale & retail | 2025 |
| Andkeel Limited | Administrative & support | 2010 |
| Andor Technology Limited | Manufacturing | 1989 |
| Andrew Clements Partnership Ltd | Financial services | 2006 |
| Andrew Collins Ltd | Wholesale & retail | 2023 |
| Andrew D Trimble Ltd | Arts & recreation | 2015 |
| Andrew Dunlop Home Interiors Limited | Professional & scientific | 2024 |
| Andrew Dunlop Homes 4 Ltd | Construction | 2025 |
| Andrew Dunlop Homes Limited | Construction | 2023 |
| Andrew G. Crawford & Company Limited | Professional & scientific | 2010 |
| Andrew Irwin Racing Limited | Arts & recreation | 2018 |
| Andrew James Park Limited | Manufacturing | 2024 |
| Andrew James Smith Ltd | Wholesale & retail | 2025 |
| Andrew James West Ltd | Wholesale & retail | 2025 |
| Andrew Kelly Painting DEC Ltd | Construction | 2022 |
| Andrew Mcdonald Marine Ltd | Construction | 2017 |
| Andrew Mulvenna Hair Limited | Other services | 2000 |
| Andrew Spring Limited | Agriculture & fishing | 2019 |
| Andrew Watson (NI) Ltd. | Wholesale & retail | 2010 |
| Andrewderetail Ltd | Wholesale & retail | 2025 |
| Andrews & Gregg Lettings Belfast Ltd | Real estate | 2017 |
| Andrews & Gregg North Down Ltd | Real estate | 2019 |
| Andrews & Gregg Sales Belfast Ltd | Real estate | 2017 |
| Andrews Flour Mills Limited | Manufacturing | 2015 |
| Andrews Group Limited | Financial services | 2015 |
| Andri Wnedk Ltd | Wholesale & retail | 2024 |
| Andshar Limited | Financial services | 2026 |
| Andyforty Global Software Solutions Ltd | Information & communication | 2022 |
| Aneesa Prime Ltd | Wholesale & retail | 2025 |
| Aneo Ltd | Wholesale & retail | 2023 |
| ANF Acquisitions Ltd | Real estate | 2020 |
| ANG Engineering Consultants Ltd | Professional & scientific | 2016 |
| ANG Michael Vincent Ltd | Wholesale & retail | 2025 |
| Angad Food Limited | Hospitality | 2018 |
| Angel Eyes NI Services | Information & communication | 2015 |
| Angel Oak Care Ltd | Health & social care | 2025 |
| Angel Touch Belfast Ltd | Health & social care | 2025 |
| Angel-Touch Limited | Extraterritorial | 2003 |
| Angela Restaurant Ltd | Hospitality | 2023 |
| Angels' Share, Belfast Ltd | Hospitality | 2024 |
| Anger Hammer Ltd | Manufacturing | 2024 |
| Angle Comms Limited | Professional & scientific | 2020 |
| Anglia & General Developments Limited | | 1984 |
| Anglo Chinese Trading Company Ltd | Administrative & support | 2009 |
| Anglo Commerce Partners Limited | Wholesale & retail | 2025 |
| Angloasset L.P. | | 2017 |
| Angm & Co UK Limited | Hospitality | 2024 |
| Angoka Limited | Manufacturing | 2019 |
| Angsana Brands PTE Ltd | Wholesale & retail | 2026 |
| Angus Properties Limited | Real estate | 2013 |
| Anhaga Ltd | Arts & recreation | 2023 |
| Animal Manager Limited | Information & communication | 2019 |
| Animated Creative Ltd | Information & communication | 2026 |
| Animotive Limited | Information & communication | 2019 |
| Animus Corporation N.I Limited | Wholesale & retail | 2021 |
| Anita Adams Ltd | Wholesale & retail | 2025 |
| Anitech Solutions Limited | Administrative & support | 2025 |
| Anjali Medical Limited | Health & social care | 2016 |
| Ankita Textile Ltd | Wholesale & retail | 2023 |
| ANL Investments (NI) Ltd | Financial services | 2021 |
| ANN Holdings Limited | Hospitality | 2026 |
| ANN Trading Limited | Hospitality | 2026 |
| Anna Douglas Consulting Limited | Professional & scientific | 2016 |
| Anna Mckeever Art Ltd | Arts & recreation | 2021 |
| Annadale Avenue Management Company Limited | Households | 2009 |
| Annadale Development Limited | Households | 1982 |
| Annadale Nursing Home Limited | Health & social care | 2010 |