| Abbisouls Ltd | Health & social care | 2025 |
| Abbotswood Events Limited | Arts & recreation | 2026 |
| Abbotswood Sports Management Limited | Professional & scientific | 2025 |
| Abbte Network Limited | Wholesale & retail | 2025 |
| ABC Car Repair Limited | Wholesale & retail | 2016 |
| ABC Fitness Ltd | Arts & recreation | 2013 |
| ABC Games, Design & Development Limited | Manufacturing | 2024 |
| ABC Homecare Ltd | Health & social care | 2024 |
| ABC Investment Properties Limited | Hospitality | 2015 |
| ABC Nutrition Limited | Extraterritorial | 2012 |
| ABC Recovery Belfast Ltd | Wholesale & retail | 2022 |
| ABC Recovery NI Ltd | Wholesale & retail | 2022 |
| ABC Vehicle Recovery Ltd | Administrative & support | 2016 |
| ABC Worldwide Ltd | Wholesale & retail | 2021 |
| Abcd Diagnostics Ltd | Health & social care | 2025 |
| Abcd Restaurant NI Ltd | Hospitality | 2024 |
| Abco Kovex (N.I.) Limited | Manufacturing | 2018 |
| Abco Subsea Ltd | Construction | 2022 |
| Abcreativelabs Ltd | Wholesale & retail | 2024 |
| Abeer Salon Ltd | Other services | 2026 |
| Abegail Hermoso Ltd | Administrative & support | 2023 |
| Abel Facilities Limited | Administrative & support | 2026 |
| Abel Industrial Cleaning Limited | Administrative & support | 2026 |
| Abel Michael Ltd | Wholesale & retail | 2023 |
| Abelnce Neilrry Limited | Wholesale & retail | 2024 |
| Abelni Limited | Transport & logistics | 2025 |
| Abercorn Construction Limited | Construction | 2011 |
| Abercromby Place LLP | | 2021 |
| Abergrove Limited | Real estate | 2016 |
| Abetta Project Delivery Ltd | Professional & scientific | 2025 |
| Abey Developments Limited | Real estate | 1998 |
| Abike Foods Limited | Hospitality | 2025 |
| Ability Matters (NI) Limited | Extraterritorial | 2004 |
| Abinel Retail Ltd | Wholesale & retail | 2026 |
| Abingdon Homes Ltd | Health & social care | 2011 |
| Abingdon Manor Care Centre Limited | Health & social care | 1997 |
| Abismmo UK Ltd | Information & communication | 2026 |
| Aboteks Industries LP | | 2017 |
| About Blank Creative Limited | Administrative & support | 2017 |
| About YE! Limited | Wholesale & retail | 2025 |
| Abpg Ltd | Wholesale & retail | 2019 |
| Abraham Engineering and Educational Consultancy Limited | Information & communication | 2014 |
| Abrfs Ltd | Wholesale & retail | 2007 |
| Abri Ltd | Construction | 2017 |
| Absalg Limited | Professional & scientific | 2022 |
| Absorbopak Global Limited | Manufacturing | 2014 |
| ABT LP | | 2007 |
| ABU Holdings Limited | Financial services | 2021 |
| ABU Tareq Ltd | Hospitality | 2018 |
| Abundant New Life Trust | Health & social care | 2022 |
| Abundia Plastics Europe Limited | Financial services | 2020 |
| ABV Cash & Carry Limited | Wholesale & retail | 2009 |
| ABW Developments Ltd | Real estate | 2015 |
| ABÚ Wear Ltd | Wholesale & retail | 2020 |
| AC Creative Events Limited | Arts & recreation | 2022 |
| AC Human Capital Limited | Administrative & support | 2021 |
| AC Property Limited | Real estate | 2016 |
| AC Realisations Limited | | 2000 |
| AC Ventures (Belfast) Limited | Financial services | 2023 |
| ACA Forwarding Limited | Transport & logistics | 2009 |
| ACA Models Ltd | Other services | 2021 |
| Acaasa Ltd | Hospitality | 2018 |
| Acacia Path Limited | Education | 2021 |
| Academy Apartments (2007) Limited | Households | 2007 |
| Academy of Digital Skills Ltd | Information & communication | 2025 |
| Academy One Nutrition Limited | Hospitality | 2014 |
| Academy Salon Limited | Other services | 2015 |
| Acapulco Mexican Restaurant LLP | | 2013 |
| Acasca Limited | Wholesale & retail | 2025 |
| ACCELER8 Business Solutions Ltd. | Administrative & support | 2020 |
| Accelerate Accident Management Ltd | Professional & scientific | 2026 |
| Accelerate Energy Holdings Limited | Energy | 2023 |
| Accept Care Ltd | Health & social care | 2003 |
| Acceptifi Ltd | Education | 2026 |
| Access Centre NI Limited | Information & communication | 2010 |
| Access Scaffolding Co. (N.I.) Ltd | Construction | 2010 |
| Access Skills Ireland Limited | Education | 2001 |
| Accessibility Transport Ltd | Transport & logistics | 2026 |
| Accident Management NI Ltd | Administrative & support | 2026 |
| Accidental Live Limited | Information & communication | 2025 |
| Accidental Theatre Ltd | Arts & recreation | 2012 |
| Accidentpro Limited | Other services | 2015 |
| Accommodate Global Ltd | Real estate | 2025 |
| Accord Assets L.P. | | 2018 |
| Accord Northern Ireland Catholic Marriage Care Service | Other services | 2014 |
| Accountsify Limited | Extraterritorial | 2013 |
| Accountsready Limited | Professional & scientific | 2023 |
| Accpro Recruitment Ltd | Administrative & support | 2025 |
| Accuprop Limited | Real estate | 2018 |
| Acdc Pharma Ltd | Financial services | 2024 |
| Ace Autofix Limited | Wholesale & retail | 2025 |
| Ace Bates Skip Hire Limited | Water & waste | 1996 |
| Ace Care Constru Ltd | Wholesale & retail | 2023 |
| Ace Diagnostics Ltd | Health & social care | 2026 |
| Ace Diamond Drilling Limited | | 1998 |
| Ace of Diamonds N.I. Ltd | Wholesale & retail | 2026 |
| Ace Trans and Trading Limited | Wholesale & retail | 2016 |
| ACE23 Ltd | Professional & scientific | 2023 |
| ACE45 Limited | Information & communication | 2020 |
| Acend Consulting Limited | Professional & scientific | 2018 |