| BMG Studios Ltd | Information & communication | 2023 |
| Bmkd Ltd | Construction | 2026 |
| BML Building Ltd | Construction | 2016 |
| BML Plumbing and Heating Ltd | Construction | 2024 |
| BMP Furniture Ltd | Manufacturing | 2004 |
| BMS Mourne Ltd | Manufacturing | 2004 |
| BN Hire Ltd | Wholesale & retail | 2018 |
| BND Property Investments Ltd | Real estate | 2026 |
| Boconnell Court Management Limited | Households | 2009 |
| BOD Renewables Ltd. | Professional & scientific | 2025 |
| BOG Road Management Co Limited | Households | 2009 |
| Boley Inn Ltd | Hospitality | 2025 |
| Bolster Community | Education | 2018 |
| Bolt Creative Ltd | Arts & recreation | 2026 |
| Bolt-On Fasteners Limited | Wholesale & retail | 2023 |
| Bonds Consulting Ltd | Professional & scientific | 2021 |
| Bonika Industries Limited | Wholesale & retail | 2023 |
| Bonlex Trading L.P. | | 2017 |
| Bonumcorpus (NO. 53) Limited | Manufacturing | 2019 |
| Boost Bikes Limited | Manufacturing | 2013 |
| Border Jack's Limited | Wholesale & retail | 2021 |
| Border Skip Hire Ltd | Water & waste | 2023 |
| Border Taxi Newry Ltd | Transport & logistics | 2016 |
| Borderline Auto Parts Limited | Wholesale & retail | 2022 |
| Boson Tech Limited | Information & communication | 2025 |
| Bounce & Jump Ltd | Arts & recreation | 2010 |
| Bovery Limited | Extraterritorial | 2010 |
| Bow's Boutique Ltd | Wholesale & retail | 2014 |
| Box-It (Ireland) Limited | Manufacturing | 2006 |
| Boyd Enterprises (Evesham) Limited | Real estate | 2017 |
| Boyds Catering Limited | Hospitality | 2025 |
| Boyds Diner Ltd | Hospitality | 2022 |
| Boyle & Co Accountants (IRE) Limited | Professional & scientific | 2017 |
| Boyle Bingo Ltd | Arts & recreation | 2019 |
| Boyle Electrical Contracts Limited | Construction | 2019 |
| Boyle Property Holdings Ltd | Real estate | 2025 |
| Boyle Snooker Ltd | Arts & recreation | 2018 |
| Boyle Transport (NI) Ltd | Transport & logistics | 2011 |
| Boylebet Limited | Arts & recreation | 2001 |
| BOYLES247 Limited | Arts & recreation | 2026 |
| Boylesports Leisure Developments (NI) Ltd | Arts & recreation | 2006 |
| BPK Assets L.P. | | 2015 |
| BPS Asset Protection Limited | Financial services | 2013 |
| BPT Construction Limited | Construction | 2015 |
| BPT Property Limited | Construction | 2025 |
| BR Excavations Ltd | Construction | 2023 |
| Braaap Cloud Ltd. | Extraterritorial | 2023 |
| Brac Ventures Limited | Real estate | 2014 |
| Brack Tours Northern Ireland Limited | Administrative & support | 2021 |
| Brackenagh Transport Limited | Transport & logistics | 2019 |
| Brackenview Hill Farm Ltd | Agriculture & fishing | 2026 |
| Bradbury Corporation Ltd | Real estate | 2021 |
| Bradley Estates NI Limited | Real estate | 2017 |
| Bradport Inter L.P. | | 2017 |
| Bradshaw's Place Management Company Limited | Households | 2005 |
| Braetec Ltd | Real estate | 2014 |
| Braetec Urban Vision Ltd | Construction | 2025 |
| Braham Hire Limited | Construction | 2022 |
| Braham Mechanical Services Limited | Construction | 2020 |
| Bramack Limited | Financial services | 2025 |
| Bramasolie Enterprise's Limited | Manufacturing | 2024 |
| Bramblewood Developments LLP | | 2025 |
| Bramblewood Limited | Financial services | 2013 |
| Brand Ready Ltd | Professional & scientific | 2025 |
| Brannock Contracts Ltd | Construction | 2017 |
| Brannock Trading Limited | Construction | 2013 |
| Branán Collective Ltd | Manufacturing | 2025 |
| Bravaro Safety Ltd | Professional & scientific | 2025 |
| Bravo Live Ltd | Hospitality | 2016 |
| Bream Properties Limited | Real estate | 2018 |
| Breen Developments Ltd | Real estate | 2022 |
| Breen Holdings Limited | Professional & scientific | 1999 |
| Breffni Air (UK) Limited | Construction | 2011 |
| Breffni Air Installations (UK) Ltd | Construction | 2024 |
| Brendan Bellew Contracts Limited | Construction | 2018 |
| Brexit Fuels Ltd | Wholesale & retail | 2018 |
| Brexit Oils Limited | Manufacturing | 2020 |
| Brexporters Limited | Manufacturing | 2020 |
| Brian a Mooney Ltd | Wholesale & retail | 2008 |
| Brian Fearon SG Holdings Limited | Financial services | 2023 |
| Brian Morgan Plastering Limited | Construction | 2016 |
| Brian Murray Contractors Ltd | Construction | 2026 |
| Brian Rice Garden Services and Home Maintenance Ltd | Administrative & support | 2025 |
| Brian Thomas O'Hare Ltd | Hospitality | 2010 |
| Bric Bagels Ltd | Hospitality | 2015 |
| Brickmore Construction Limited | Construction | 2014 |
| Brickscaff Ltd | Construction | 2009 |
| Brictek Ltd | Construction | 2015 |
| Bridgegate Property Group Limited | Construction | 2026 |
| Bridgelea Apartments Management (NO2) Company Limited | Construction | 2015 |
| Bridgelea Apartments Management Company (NO 1) Limited | Real estate | 2012 |
| Bridgelea Management Company Limited | Real estate | 2010 |
| Bridges Management Company Limited - the | Households | 2005 |
| Bridgestone Mcgroder Quarries Ltd | Mining & quarrying | 2024 |
| Bridgeview Estates Ltd | Real estate | 2025 |
| Bridgeview Logistics Ltd | Transport & logistics | 2016 |
| Bridgeview Trading Ltd | Hospitality | 2014 |
| Bright Places Counselling Services | Administrative & support | 2020 |
| Brilliant Red Developments Limited | Information & communication | 2017 |
| Brilliant Red Digital Ltd | Information & communication | 2019 |