| 1013 Training Limited | Education | 2017 |
| 121 Sound Services Ltd | Manufacturing | 2025 |
| 153 Templemore Management Company Limited | Households | 2022 |
| 1823SAMRINE Company Limited | Health & social care | 2024 |
| 1ACER Limited | Financial services | 2026 |
| 1LIFE Accounting Ltd | Professional & scientific | 2026 |
| 1LIFEPROJECTS Ltd | Real estate | 2021 |
| 2007 GAL Limited | Professional & scientific | 2004 |
| 360 Energy (N.I.) Limited | Professional & scientific | 2016 |
| 360 Surveys (NI) Ltd | Professional & scientific | 2011 |
| 3CS Cleaning & Installation Services Ltd | Administrative & support | 2020 |
| 3V3 Sports NI Limited | Arts & recreation | 2025 |
| 4 Winds Property Ltd | Households | 2025 |
| 565 Ltd | Real estate | 2020 |
| 66 Atelier Limited | Construction | 2025 |
| 7 Summits Consultancy Limited | Professional & scientific | 2019 |
| 727 Your Store Limited | Wholesale & retail | 2013 |
| 8 Wellington Park Avenue Management Companu Limited | Households | 2023 |
| 82 Causeway Limited | Hospitality | 2021 |
| 86 Causeway Limited | Hospitality | 2021 |
| A & B Industrial Cleaning (N.I.) LLP | | 2019 |
| A & B Pneumatics Limited | Manufacturing | 2005 |
| A & R Horizon Homes Ltd | Real estate | 2022 |
| A & SW Farms Ltd | Agriculture & fishing | 2026 |
| A Black Contracts Ltd | Construction | 2019 |
| A G Wilson Limited | Construction | 2010 |
| A H and M (Holdings) Limited | Financial services | 2019 |
| A J Construction (Lurgan) Ltd | Construction | 2011 |
| A Jamison Vehicle Maintenance & Repair Ltd | Wholesale & retail | 2025 |
| A Logan Solutions Limited | Construction | 2021 |
| A MC a Builders Limited | Construction | 2006 |
| A Plus Motoring Academy Limited | Education | 2017 |
| A to B Storage Limited | Transport & logistics | 2019 |
| A W Mitchell Electrical Services Ltd | Construction | 2022 |
| A W R Jamison Limited | Construction | 2005 |
| A-2-B Coaches N.I. Limited | Transport & logistics | 2024 |
| A.A.E.S. (Ireland) Ltd | Extraterritorial | 2019 |
| A.C. Powerlines Ltd | Energy | 1999 |
| A.C.E.Rogan (Consultancy) Ltd | Professional & scientific | 2007 |
| A.E.S Enterprises Ltd | Hospitality | 2019 |
| A.J. Power Limited | Manufacturing | 2003 |
| A.L. Hearthstone Ltd | Real estate | 2026 |
| A.T. Europe Ltd | Construction | 2026 |
| A1 Construction Services Ltd | Construction | 2013 |
| A1 Rewinds Ltd | Manufacturing | 2015 |
| A1 Site Surveys NI Limited | Construction | 2017 |
| Aangelov Ltd | Construction | 2023 |
| AAR Rentals Limited | Real estate | 2023 |
| Aaron Buys Cars Ltd | Wholesale & retail | 2024 |
| AB Kebab Limited | Hospitality | 2024 |
| AB Refrigeration & Air Conditioning Ltd | Wholesale & retail | 2003 |
| Abbb Catering Limited | Hospitality | 2024 |
| Abbey Street Investments Limited | Real estate | 2024 |
| Abbney Homes Ltd | Construction | 2021 |
| Abbs Services Ltd | Health & social care | 2020 |
| Abbycare Home Services Ltd | Health & social care | 2025 |
| ABC Autism Group CIC | Health & social care | 2022 |
| ABC Auto Sales Ltd | Wholesale & retail | 2024 |
| ABC Bins Ltd | Water & waste | 2022 |
| ABC Community Network | Professional & scientific | 1999 |
| ABC JET Car Wash Limited | Wholesale & retail | 2025 |
| ABC Operations Ltd | Transport & logistics | 2019 |
| ABC Travel Solutions (NI) Ltd | Transport & logistics | 2022 |
| ABC Waste Management Ltd. | Water & waste | 2010 |
| Abzni Limited | Other services | 2023 |
| AC Wind Power Ltd | Energy | 2012 |
| Accept Crypto UK Ltd | Information & communication | 2026 |
| Access 24/7 Care Ltd | Public administration | 2025 |
| Accessible Resources Ltd | Information & communication | 2022 |
| Accounting & Consulting (NI) Limited | Professional & scientific | 2013 |
| Acett Ltd | Arts & recreation | 2021 |
| Acheson Carson Optical Ltd | Health & social care | 2020 |
| Acl.Man.Eng.Services Ltd | Professional & scientific | 2022 |
| Acorns 2 Oaks Enterprises Ltd | Real estate | 2016 |
| Actv Limited | Wholesale & retail | 2022 |
| AD Homes Ltd | Real estate | 2018 |
| Adarcadia Ltd | Professional & scientific | 2025 |
| ADB Retail Ltd | Wholesale & retail | 2019 |
| Adbel Ltd | Real estate | 2024 |
| Adco Distributors (NI) Limited | Manufacturing | 2011 |
| ADD Consulting Engineers Ltd | Professional & scientific | 2023 |
| Adelmi Ltd | Manufacturing | 2020 |
| ADG Group Holdings Ltd | Financial services | 2016 |
| Adla Property Holdings NI Ltd | Real estate | 2026 |
| Admarrow Limited | Information & communication | 2026 |
| Adow Construction Management Services Ltd | Construction | 2022 |
| Adverra Digital Ltd | Professional & scientific | 2025 |
| AE Comfy Ltd | Wholesale & retail | 2025 |
| Aero Powered Access Ltd | Manufacturing | 2025 |
| Aerotec Systems and Software Ltd. | Information & communication | 2016 |
| Aeternum Consilium Ltd | Administrative & support | 2025 |
| AG Asset Finance Ltd | Financial services | 2018 |
| AG Personal Training Limited | Arts & recreation | 2026 |
| AGD Innovations Ltd | Manufacturing | 2025 |
| Aggai Ltd | Professional & scientific | 2025 |
| Aggcycle Engineering Ltd | Manufacturing | 2026 |
| Aghalee Pharmacy Practice Ltd | Wholesale & retail | 2004 |
| Agile Nexus Ltd | Information & communication | 2025 |
| AGM Construction and Cost Management Ltd | Construction | 2025 |
| Agnail Recovered Resources Limited | Water & waste | 2018 |