| Atlantic Quay Limited | Professional & scientific | 2020 |
| Atlantic Quay Management Company Limited | Real estate | 2002 |
| Atlas Roots Ltd. | Professional & scientific | 2021 |
| AUBURN89 Ltd | Real estate | 2026 |
| Aught Ventures Ltd | Real estate | 2022 |
| Auto-Mate Consultants Limited | Information & communication | 2025 |
| Avaritia Limited | Real estate | 2022 |
| AVC Property Maintenance Ltd | Construction | 2023 |
| Avert Enterprises Ltd. | Education | 2010 |
| Awakenangels Limited | Administrative & support | 2023 |
| Awakenhub Ltd | Information & communication | 2020 |
| Aware Defeat Depression | Professional & scientific | 1996 |
| Axis Motor Corporation Ltd | Manufacturing | 2023 |
| Axle Security Ltd | Administrative & support | 2025 |
| Ayton Transport (NI) Limited | Transport & logistics | 2017 |
| B Doherty Construction Limited | Construction | 2021 |
| B Doherty Screeding NI Ltd | Construction | 2015 |
| B H P Security Systems Limited | Extraterritorial | 1998 |
| B MC G Construction Limited | Construction | 2021 |
| B Mccolgan Holdings Limited | Financial services | 2025 |
| B T Cartmill Limited | Health & social care | 2014 |
| B Willis & SON Construction Ltd | Construction | 2017 |
| B. Mccolgan Limited | Manufacturing | 2020 |
| BAD Apple Apps Ltd | Information & communication | 2024 |
| Balcro Ltd | Professional & scientific | 2025 |
| Ballyarton Energy Limited | Extraterritorial | 2010 |
| Ballycairn Farms Ltd | Agriculture & fishing | 2008 |
| Ballycrum Hydro Limited | Energy | 2012 |
| Ballyh Holdings Limited | Financial services | 2025 |
| Ballyhan Interiors Ltd | Construction | 2025 |
| Ballymac Stores Ltd | Wholesale & retail | 2014 |
| Ballymagroarty Mobile Shop Ltd | Wholesale & retail | 2024 |
| Ballymonie Developments Limited | Construction | 2016 |
| Ballyness Renewables Limited | Energy | 2012 |
| Ballyorr Inns Limited | Hospitality | 2012 |
| Ballysillan Road Limited | Real estate | 2013 |
| Bambeeni Ltd | Wholesale & retail | 2024 |
| Bang on the Door Limited | Arts & recreation | 2000 |
| Bangiven Holdings Ltd | Financial services | 2026 |
| Bangiven Projects Ltd | Construction | 2026 |
| Bangkok Taste Kitchen Ltd | Hospitality | 2019 |
| Barnailt Electrical Ltd | Construction | 2022 |
| Barrs Takeaway Beechwood Ltd | Hospitality | 2018 |
| Barrs Takeaway Brandywell Ltd | Hospitality | 2018 |
| Base One Europe Beech Hill Limited | Arts & recreation | 2010 |
| Bastion Property (Londonderry) Limited | Real estate | 1991 |
| Bayfield Glenturas Developments Ltd | Construction | 2021 |
| Bayview House Management Company Ltd | Real estate | 2007 |
| Bayview Living Limited | Hospitality | 2024 |
| BB Management (N.I.) Limited | Professional & scientific | 2018 |
| BBS Consulting Services Limited | Professional & scientific | 2023 |
| BC Contracts Ireland Ltd | Construction | 2006 |
| BC Donaghy & Sons Ltd | Professional & scientific | 2024 |
| Bcle Commerce Limited | Wholesale & retail | 2024 |
| BCT Curry Limited | Wholesale & retail | 2014 |
| BD Hospitality Ltd | Hospitality | 2026 |
| BDN Energy Ltd | Construction | 2023 |
| BDQ Consulting Ltd | Information & communication | 2025 |
| BDV Pacific Holdco Ltd | Construction | 2021 |
| Beach Rentals Ltd | Administrative & support | 2018 |
| Beach TAN Ltd | Other services | 2024 |
| Bean Jason Ltd | Wholesale & retail | 2024 |
| Beautiful Faces Ltd | Other services | 2026 |
| Beaver LOG Cabins Limited | Manufacturing | 2011 |
| BEE Eaters Ltd | Hospitality | 2022 |
| Beech Hill House Hotel Limited | Hospitality | 2003 |
| Beechend Limited | Real estate | 1999 |
| Beechwood Construction and Services Ltd | Construction | 2022 |
| Beechwood Enterprises (Derry) Limited | Arts & recreation | 2024 |
| Beechwood Properties (Derry) Ltd | Real estate | 2017 |
| Bella MIA .App Ltd | Hospitality | 2025 |
| Bellandsonprehen Ltd | Construction | 2016 |
| Belmont Investment Properties Limited | Real estate | 2016 |
| Belpat Limited | Wholesale & retail | 2021 |
| Ben-Eden Enterprises Ltd | Hospitality | 2022 |
| Benahavis Holdings Ltd | Construction | 2021 |
| Benbradagh Estates Ltd | Real estate | 2020 |
| Benone Fishing Company Limited | Agriculture & fishing | 2004 |
| Benone Retreat Ltd | Hospitality | 2024 |
| Benone Spa Ltd | Other services | 2025 |
| Beragh Hill Ltd | Real estate | 2014 |
| Beragh Hill NO 2 Limited | Real estate | 2020 |
| Beraghmore Properties Ltd | Real estate | 2020 |
| Berko POD Systems Ltd | Construction | 2020 |
| Berngar Ltd | Administrative & support | 2000 |
| Besom Productions Limited | Information & communication | 1991 |
| Bespoke Interiors (IRL) Ltd | Wholesale & retail | 2020 |
| Betr Solutions Limited | Professional & scientific | 2024 |
| Betty & Bill Limited | Manufacturing | 2024 |
| Bexit Ltd | Information & communication | 2018 |
| BGF Promotions Ltd | Wholesale & retail | 2020 |
| BHE Creative Ltd | Information & communication | 2010 |
| Bhrl Investments Limited | Real estate | 2015 |
| BI General Trading Ltd | Hospitality | 2025 |
| Big Bear Investments Limited | Real estate | 2012 |
| Big Daddy Deals Limited | Wholesale & retail | 2020 |
| Big O Cafe Limited | Hospitality | 2019 |
| Bigwood Management Company Limited | Households | 2025 |
| Billiúin Limited | Administrative & support | 2022 |
| Billy Henderson Properties Limited | Construction | 2007 |