| Bert Trans Ltd | Transport & logistics | 2022 |
| Besides Money Limited | Financial services | 2016 |
| Bespoke Educational Software Limited | Information & communication | 2015 |
| Bessbrook Development Company Limited | Real estate | 1993 |
| Bessbrook Pharmacy Ltd | Wholesale & retail | 2003 |
| Bessbrook Solutions Limited | Construction | 2025 |
| Bessbrook Townhall Ltd | Arts & recreation | 2021 |
| Bessie Developments Ltd | Construction | 2024 |
| Best Util Construct SRL Limited | Manufacturing | 2020 |
| Bettys Care Ltd | Health & social care | 2020 |
| Beverly Wilson Food Consultancy & Training Limited | Professional & scientific | 2013 |
| Beyond the Branding Ltd | Professional & scientific | 2023 |
| BF Holdings Group Ltd | Financial services | 2020 |
| BF Services Limited | Wholesale & retail | 2015 |
| BFG Properties Ltd | Hospitality | 2025 |
| BFM Deals Limited | Wholesale & retail | 2023 |
| BGP Plastering Ltd | Construction | 2024 |
| BGQ Ltd | Health & social care | 2014 |
| BH Services Group Ltd | Construction | 2025 |
| Bhandara Limited | Hospitality | 2025 |
| BHP Accountants Ltd | Professional & scientific | 2006 |
| Bhqss Holdings Ltd | Professional & scientific | 2026 |
| Bid-Ma Bistro Ltd | Hospitality | 2017 |
| Bidrops Limited | Information & communication | 2026 |
| Big Bites Indian Takeaway Limited | Hospitality | 2023 |
| Big Daddy Foods Limited | Financial services | 2021 |
| Big Gate Holdings Limited | Financial services | 2024 |
| Big Joes Sales Recovery’S LDT Ltd | Water & waste | 2026 |
| Big Mountain Productions Limited | Information & communication | 2005 |
| Bikeloxz Limited | Manufacturing | 2023 |
| Billcroft Trading L.P. | | 2016 |
| BIM Tech Engineering (Ireland) Limited | Professional & scientific | 2026 |
| Binarypriv Ltd | Information & communication | 2021 |
| Binnian Fishing Ltd | Agriculture & fishing | 2017 |
| Bint Property Ltd | Real estate | 2025 |
| Bio-Hack-Kins Ltd | Health & social care | 2025 |
| Biobridge Scientific Limited | Professional & scientific | 2018 |
| Biofires Ireland Limited | Administrative & support | 2009 |
| BIP Limited | Hospitality | 2025 |
| Birch Coffee Ltd | Hospitality | 2021 |
| Birchlea Trading Company Ltd | Wholesale & retail | 2003 |
| Birchwood Joinery Limited | Manufacturing | 2024 |
| Birds Amusements Limited | Arts & recreation | 2020 |
| Birthwise | Administrative & support | 2019 |
| BJF Training Services Ltd | Information & communication | 2015 |
| BJF Transport Compliance & Training Ltd | Information & communication | 2025 |
| BJH Trading Ltd | Wholesale & retail | 2013 |
| BJV Developments Ltd | Construction | 2019 |
| BK Building Contracts Ltd | Construction | 2018 |
| BK Direct Supplies Ltd | Construction | 2008 |
| BK Full Circle UK Ltd | Wholesale & retail | 2024 |
| BK on the Go Limited | Hospitality | 2019 |
| BK Property Enterprises Ltd | Construction | 2024 |
| Black Forest Joinery Ltd | Manufacturing | 2023 |
| Black Gate Developments Ltd | Construction | 2016 |
| Black Shed Thoughts Ltd | Professional & scientific | 2020 |
| Blackart Engineering Limited | Professional & scientific | 2015 |
| Blackhill Wind Ltd | Energy | 2013 |
| Blackmourne Contracts Ltd | Manufacturing | 2025 |
| Blackrock Cars Limited | Wholesale & retail | 2025 |
| Blackrock Contracts (NI) Limited | Administrative & support | 2019 |
| Blackrock Electrical (N.I.) Ltd | Construction | 2022 |
| Blackthorn Furniture Ltd | Manufacturing | 2012 |
| Blackthorn Property Management Ltd | Real estate | 2014 |
| Bladecycle Solutions Ltd | Water & waste | 2025 |
| Blaney Mediation Collaborative Ltd | Professional & scientific | 2024 |
| Blaney Road Poultry Limited | Extraterritorial | 2025 |
| Blantyre Consultants Limited | Professional & scientific | 2009 |
| Blast 106 Limited | Wholesale & retail | 2010 |
| Blast the Past Cleaning Services Ltd | Administrative & support | 2026 |
| BLAST106 Digital Ltd | Wholesale & retail | 2023 |
| BLC Contracts Limited | Construction | 1998 |
| BLC Property Services Ltd | Real estate | 2026 |
| Blend and Batch Limited | Hospitality | 2019 |
| Bliary Stone UK Ltd | Mining & quarrying | 2018 |
| Blisslow Limited | Hospitality | 2022 |
| Block Management (N.I.) Ltd | Real estate | 2012 |
| Blockbusters Environmental Services (NI) Limited | Water & waste | 2014 |
| Blu-Water Ltd | Real estate | 2023 |
| Blue Azul Limited | Water & waste | 2019 |
| Blue Bubbles Car Wash Limited | Administrative & support | 2022 |
| Blue Lion Group Limited | Financial services | 2026 |
| Blue Print Pizza Co Ltd | Hospitality | 2025 |
| Blue Sugar Limited | Hospitality | 2026 |
| Blueapple Dental and Implant Team Limited | Health & social care | 2012 |
| Blueberry Hearing Services Ltd | Health & social care | 2019 |
| Bluechip Title Solutions Ltd | Financial services | 2007 |
| Bluechoice Limited | Wholesale & retail | 2026 |
| Bluecool Water Dispensers Limited | Construction | 2009 |
| Bluestar Contracts Ltd | Construction | 2014 |
| Bluezone Scientific Limited | Professional & scientific | 2020 |
| Bluezone Technologies Ltd. | Information & communication | 2015 |
| BM Financial Services Ltd | Professional & scientific | 2001 |
| BM Fishing Company Ltd | Agriculture & fishing | 2011 |
| BM Joinery(Ni) Ltd | Construction | 2024 |
| BMC Accountants Ltd | Professional & scientific | 2015 |
| BMC Consultancy (N.I.) Ltd | Professional & scientific | 2018 |
| BMC Freight Limited | Transport & logistics | 2015 |
| BMC Taxation Ltd | Professional & scientific | 2003 |
| BMD Consulting Ltd | Professional & scientific | 2024 |