| 39A Ltd | Wholesale & retail | 2024 |
| A & a Morrow Consultancy Ltd | Other services | 2015 |
| A W Wilson Metal Work and Training Limited | Manufacturing | 2017 |
| A.T. Engineering Ltd | Construction | 2013 |
| A.T. Mechanical & Welding Services Ltd | Agriculture & fishing | 2019 |
| A1 Decorators Ltd | Construction | 2014 |
| AB Cabs Ltd | Transport & logistics | 2015 |
| Access Employment Ltd | Wholesale & retail | 1998 |
| Access Safety Testing Ltd | Professional & scientific | 2022 |
| Accounting Investments Ltd | Administrative & support | 2020 |
| Ace Developements Larne Limited | Construction | 2016 |
| Ace Recovery Services Ltd | Transport & logistics | 2025 |
| Ace Tanning Studio Limited | Other services | 2025 |
| ACG Trees Limited | Administrative & support | 2025 |
| Achill Rock Enterprises Limited | Construction | 2016 |
| Achill Rock Limited | Extraterritorial | 2016 |
| Aculeate Limited | Real estate | 1992 |
| AD Sustainability Consultancy Ltd | Professional & scientific | 2013 |
| ADA Services (N.I.) Limited | Manufacturing | 2017 |
| Adsc Ltd | Professional & scientific | 2021 |
| Adventure After 30 Ltd | Administrative & support | 2026 |
| Agricultai Limited | Wholesale & retail | 2025 |
| AGS (N.I) Ltd | Wholesale & retail | 2025 |
| Ahara Haven Ltd | Hospitality | 2024 |
| Aijs (N.I) Ltd | Arts & recreation | 2023 |
| Ailsa View Management Company Limited | Households | 2016 |
| Airgen Ireland Ltd | Professional & scientific | 2026 |
| AJ Design Consultancy Ltd | Professional & scientific | 2024 |
| AL Mart Ltd | Wholesale & retail | 2025 |
| Alex Magill Hair NI Ltd | Other services | 2025 |
| Alpco Ltd | Wholesale & retail | 2014 |
| Andy School of Motoring Ltd | Administrative & support | 2014 |
| Anlaimh Ltd | Professional & scientific | 2013 |
| Ansal Predator Control Ltd | Administrative & support | 2026 |
| Antrim Coast Vineyard Church | Other services | 2018 |
| Antrim Farmers Harvest Limited | Wholesale & retail | 2025 |
| Apex Performance (N.I.) Ltd | Arts & recreation | 2024 |
| APM (N.I.) Ltd | Administrative & support | 2022 |
| Apollo Ceilings Ltd | Construction | 2018 |
| Arbor Hills Ltd | Hospitality | 2022 |
| Arcex Limited | Professional & scientific | 2010 |
| ARK MW Properties (N.I.) Ltd | Real estate | 2019 |
| Arnott Knowe Farms Ltd | Agriculture & fishing | 2025 |
| Arranmore Ltd | Extraterritorial | 2018 |
| Articlave Enterprise Limited | Real estate | 2025 |
| Asap Cargo Ltd | Transport & logistics | 2007 |
| Asfs (N.I.) Ltd | Extraterritorial | 2017 |
| Assure Services (NI) Ltd | Construction | 2011 |
| ATC Plus Ltd | Professional & scientific | 2023 |
| Aviation Solutions KB Ltd | Manufacturing | 2021 |
| B H Logistics Consultancy Limited | Professional & scientific | 2022 |
| B&L Global Recruitment Ltd | Administrative & support | 2024 |
| B.I.L Furnishings Ltd | Wholesale & retail | 2019 |
| B9 Biogas Ltd | Extraterritorial | 2011 |
| B9 Energy Control Ltd | Energy | 2008 |
| B9 Energy Development Ltd | Professional & scientific | 2001 |
| B9 Energy Group Limited | Administrative & support | 2018 |
| B9 Energy Horizons Ltd | Energy | 2019 |
| B9 Energy Limited | Administrative & support | 1999 |
| B9 Energy Services Limited | Professional & scientific | 2018 |
| B9 Energy Storage Ltd | Construction | 2011 |
| B9 Feedstocks Limited | Water & waste | 2018 |
| B9 Fertiliser Ltd | Water & waste | 2018 |
| B9 Food Recovery Limited | Water & waste | 1999 |
| B9 Fuels Limited | Extraterritorial | 2021 |
| B9 GAS Limited | Energy | 2019 |
| B9 Heat and Power Limited | Energy | 2013 |
| B9 LFG Craigmore Ltd | Energy | 2023 |
| B9 Organic Energy Limited | Professional & scientific | 1998 |
| B9 Power Limited | Energy | 2018 |
| B9 Renovare Limited | Professional & scientific | 2022 |
| B9 Shipping Limited | Administrative & support | 2006 |
| B9 Solar Ltd | Energy | 2025 |
| B9 Solutions Limited | Professional & scientific | 2010 |
| B9H2 Ltd | Financial services | 2020 |
| B9RENEWABLES Ltd | Construction | 2025 |
| Baird Designs Ltd | Professional & scientific | 2001 |
| Ballyeaston Brea Management Company Limited | Households | 2022 |
| Ballygilbert LLP | | 2014 |
| Ballylesson Homes Limited | Real estate | 2026 |
| Ballymena Barbers (N.I.) Ltd | Other services | 2019 |
| Ballymoney Investors Limited | Real estate | 2024 |
| Ballypollard Properties Limited | Real estate | 2026 |
| Ballyrickard Investments Ltd | Households | 2026 |
| Barclay Building Construction Ltd | Construction | 2018 |
| Barline Transport Limited | | 2006 |
| Barr Cregg Energy Limited | Energy | 2020 |
| Batdj Ltd | Health & social care | 2022 |
| Batts Farm Ltd | Agriculture & fishing | 2026 |
| Bayshore Homes Limited | Construction | 2010 |
| Bayview Management NO. 1 Limited | Real estate | 2019 |
| Bcda Limited | Administrative & support | 2010 |
| Bcda Trading Limited | Administrative & support | 2010 |
| BCW (N.I.) Ltd | Wholesale & retail | 2024 |
| Be-Fit (N.I) Ltd | Arts & recreation | 2023 |
| Bearnagh Developments Limited | Real estate | 2022 |
| Bearnagh Downe Limited | Real estate | 2014 |
| Bearnagh Downe Property Limited | Construction | 2018 |
| Belfast Beard Company Ltd | Manufacturing | 2015 |
| Belfast Playbus Limited | Arts & recreation | 2017 |