| 2 Northland Ltd | Real estate | 2020 |
| 323 Dash 7 Ltd | Hospitality | 2025 |
| 3EAST Ltd | Real estate | 2022 |
| 5015 Finance Limited | Financial services | 2016 |
| 5M Contracts Limited | Construction | 2026 |
| 6S Properties Limited | Real estate | 2014 |
| 6S Property Management Ltd | Real estate | 2017 |
| 9 Petals Ltd | Wholesale & retail | 2025 |
| A & D Mcivor Ltd | Agriculture & fishing | 2025 |
| A MAC Electrics Ltd | Construction | 2021 |
| A Primeira Limited | Wholesale & retail | 2024 |
| A&A Properties (N.I.) Limited | Real estate | 2016 |
| A&J Harkness Ltd | Wholesale & retail | 2022 |
| A-Met Engineering Limited | Construction | 2011 |
| A. Hughes (Cookstown), Limited | Real estate | 1953 |
| A. Scullin Electrics Ltd | Energy | 2019 |
| A.J Walsh Ltd | Professional & scientific | 2026 |
| A.M. Innovation Limited | Professional & scientific | 2018 |
| AAA Biomass Services Ltd | Construction | 2018 |
| Abbey BIO Fibre Products Limited | Agriculture & fishing | 2020 |
| ABM Donnelly Properties Ltd | Real estate | 2026 |
| Ackermann Medicolegal Ltd | Health & social care | 2022 |
| ACL Developments Limited | Construction | 2013 |
| Acorn Rental Ltd | Real estate | 2015 |
| Adda (N.I.) Ltd | Real estate | 2012 |
| Adeelan Ltd | Mining & quarrying | 2025 |
| Adrenaline Sportswear Ltd | Manufacturing | 2021 |
| Adrian & Co Jewellers Ltd | Wholesale & retail | 2011 |
| Advanced Electronic Solutions Global Ltd | Other services | 2009 |
| Advanced Security Distribution (NI) Ltd | Other services | 2025 |
| AED Boiler Installations Ltd | Construction | 2024 |
| AED Boiler Services Ltd | Construction | 2020 |
| Aerast Ltd | Information & communication | 2025 |
| AES Global Holdings Ltd | Financial services | 2021 |
| AES Property Holdings Ltd | Real estate | 2021 |
| AES Web Services Ltd. | Information & communication | 2015 |
| AJ Studios Ltd | Real estate | 2019 |
| Ajea Products Limited | Manufacturing | 2012 |
| AJM Sales & Hire Limited | Wholesale & retail | 2010 |
| AL Vito Ltd | Hospitality | 2018 |
| Albany CPC Limited | Wholesale & retail | 2025 |
| Albany DMS Limited | Wholesale & retail | 2008 |
| Albany Managed Print Services Limited | Wholesale & retail | 2013 |
| Allens Cookstown Ltd | Real estate | 2007 |
| Allens Pharmacy Limited | Wholesale & retail | 2015 |
| Allingham Holdings Ltd | Financial services | 2017 |
| Alphabeta Enterprises Ltd | Wholesale & retail | 2023 |
| Altrade Engineering Limited | Construction | 2021 |
| Aluplas Ireland Ltd | Manufacturing | 2001 |
| AMC Landholdings Ltd | Real estate | 2024 |
| AMC Retail Ltd | Wholesale & retail | 2010 |
| AMK Aquaculture Limited | Extraterritorial | 2014 |
| AML (N.I.) Ltd | Wholesale & retail | 2015 |
| AMR FBA Ltd | Wholesale & retail | 2025 |
| AMR Properties/Services Ltd | Real estate | 2025 |
| AMS (N.I.) Ltd | Wholesale & retail | 2019 |
| AN Comhdháil NA Múinteoirí LE Rincí Gaelacha Teoranta | Arts & recreation | 2026 |
| ANC 13 Ltd | Wholesale & retail | 2024 |
| Anderson PIG Farms Ltd | Agriculture & fishing | 2011 |
| Annaghmore Fuels Ltd | Wholesale & retail | 2018 |
| Aoife Property Limited | Real estate | 2018 |
| APC Joinery Ltd | Construction | 2022 |
| Apex Reset Ltd | Other services | 2026 |
| Aqua-Mech Solutions Ltd | Manufacturing | 2014 |
| ARC Developments (NI) Ltd | Construction | 2016 |
| Arcen (Ireland) Ltd | Professional & scientific | 2021 |
| Archewell Stables Ltd | Agriculture & fishing | 2021 |
| Architectural Planning Supervision LLP | | 2007 |
| Arcom Property Ltd | Real estate | 2012 |
| Ardagh Mechanical Limited | Construction | 2023 |
| Ardboe Agri Energy Ltd | Energy | 2012 |
| Artafex Ltd | Wholesale & retail | 2015 |
| Artea Trading Limited | Construction | 2015 |
| ASH Street Company Limited | Extraterritorial | 2016 |
| Askra Limited | Real estate | 2016 |
| Associated Construction Services Ltd | Construction | 2022 |
| Atlantic Developments (NI) Limited | Construction | 2008 |
| ATO Management Consultants Ltd | Professional & scientific | 2021 |
| Atti Holdings Limited | Construction | 2020 |
| Autocom (NI) Ltd | Manufacturing | 2012 |
| AVI Technologies Limited | Professional & scientific | 2002 |
| AW2 Advisory Ltd | Professional & scientific | 2025 |
| B & B Pizzeria Ltd | Hospitality | 2020 |
| B&S Tool Supplies Ltd | Wholesale & retail | 2017 |
| BA Clic Components Ltd | Manufacturing | 2016 |
| Bagel Bean Limited | Hospitality | 2012 |
| Ballinderry Rivers Trust | Agriculture & fishing | 2011 |
| Bally Renewables Limited | Mining & quarrying | 2017 |
| Ballycolin Wind Ltd | Energy | 2012 |
| Ballykilbeg Wind Ltd | Energy | 2014 |
| Ballylig Wind Ltd | Energy | 2016 |
| Ballymoyle Farms Limited | Agriculture & fishing | 2013 |
| Ballynahinch Bess Ltd | Energy | 2023 |
| Ballynakilly Farms Ltd | Agriculture & fishing | 2015 |
| Bameccni CIC | Education | 2021 |
| Bardun Ltd | Hospitality | 2024 |
| Barnes Farm Ltd | Energy | 2014 |
| Bathe (N.I.) Ltd | Wholesale & retail | 2018 |
| Bathe Retail Ltd | Extraterritorial | 2022 |
| Battery Bar Hospitality Ltd | Hospitality | 2025 |