| Bannon and Bannon Property (Commercial) 6 Ltd | Financial services | 2026 |
| Bannon and Bannon Property (Commercial) 7 Ltd | Financial services | 2026 |
| Bannon and Bannon Property (Commercial) Three Limited | Financial services | 2024 |
| Bannon and Bannon Property (Commercial) Two Limited | Financial services | 2024 |
| Bannon Crawford Limited | Professional & scientific | 2015 |
| Bannside Library Ltd | Information & communication | 2012 |
| Bannsiders Holdings Limited | Financial services | 2023 |
| Bannview Construction Ltd | Construction | 2026 |
| Banoge Ltd | Health & social care | 2013 |
| Banshee Games Ltd | Information & communication | 2024 |
| Banto Pinoy Bites Ltd | Hospitality | 2024 |
| Banxegang Ltd | Wholesale & retail | 2025 |
| Banyan Builds Ltd | Construction | 2024 |
| Banyan Grove Ltd | Real estate | 2026 |
| BAO YAN Ltd | Wholesale & retail | 2024 |
| Baolan Limited | Wholesale & retail | 2024 |
| Baomei Limited | Wholesale & retail | 2024 |
| Baotomei Ltd | Wholesale & retail | 2023 |
| Baowong Limited | Wholesale & retail | 2024 |
| BAP AM Limited | Professional & scientific | 2015 |
| Bap-It Foods Ltd | Hospitality | 2019 |
| Baps Belfast Limited | Hospitality | 2024 |
| Baquem Ltd | Wholesale & retail | 2024 |
| Bar Czar Limited | Professional & scientific | 2008 |
| Bar Library Nominees Limited | Professional & scientific | 2005 |
| Bar None N.I. Ltd | Hospitality | 2010 |
| Barabbas Development Ltd | Households | 2019 |
| Baramati Ltd | Information & communication | 2021 |
| Baranailt Ltd | Energy | 2014 |
| Barbican Fresh Foods Limited | Wholesale & retail | 1996 |
| Barbican Inns Limited | Hospitality | 2005 |
| Barblyn Ltd | Wholesale & retail | 2024 |
| Barbour Developments Limited | Construction | 2021 |
| Barbour Engineering & Fabrication Limited | Professional & scientific | 2022 |
| Barbour Estates Ltd | Real estate | 2016 |
| Barbour Residential Limited | Real estate | 2021 |
| Barclay Communications Group Limited | Extraterritorial | 2023 |
| Barclay Communications Ltd | Information & communication | 2015 |
| Barclay Digital Services Ltd | Information & communication | 2014 |
| Barclay Telecom Limited | Information & communication | 2008 |
| Barebel Limited | Administrative & support | 2023 |
| Barel Limited | Hospitality | 2011 |
| Barking Films Ltd | Information & communication | 2005 |
| Barkley and Waggins Ltd | Wholesale & retail | 2020 |
| Barleygold Limited | Professional & scientific | 1997 |
| Barnam's World of Ice Cream Ltd | | 2005 |
| Barnams Cafe World of Ice Cream Ltd | Hospitality | 2012 |
| Barnes Contracts (NI) Limited | Construction | 2008 |
| Barnes Mcalister Limited | Real estate | 2024 |
| Barnett Silos Limited | Wholesale & retail | 1991 |
| Barnetts Chase Management Company Limited | Households | 2001 |
| Barnetts Court Estates Limited | Extraterritorial | 1998 |
| Barney Buildings Ltd | Real estate | 2020 |
| Barni Ltd | Construction | 2014 |
| Barnvale Developments Limited | Real estate | 2005 |
| Barnwell Farms Limited | Agriculture & fishing | 1996 |
| Barone Solutions Limited | Real estate | 2015 |
| Baronscourt Manor Limited | Households | 2005 |
| Baroque Limited | Wholesale & retail | 2025 |
| Barr Feabhais Limited | Professional & scientific | 2021 |
| Barr Marketing Limited | Professional & scientific | 2008 |
| Barr Productions Ltd | Information & communication | 2021 |
| Barr Properties Ltd | Professional & scientific | 2008 |
| Barre & Beyond Ltd | Arts & recreation | 2025 |
| Barrington & Salters Limited | Professional & scientific | 2018 |
| Barrley Limited | Wholesale & retail | 2025 |
| Barron & Brennan Limited | Wholesale & retail | 1951 |
| Barron North Limited | Manufacturing | 2020 |
| Barrule (UK) Limited | Arts & recreation | 2010 |
| Barry Crerar (NI) Ltd | Information & communication | 2025 |
| Barry O'Neill Boxing & Coaching Ltd | Arts & recreation | 2025 |
| Barryleve Limited | Wholesale & retail | 2024 |
| Bartholomew & James (Financial Services) Limited | Financial services | 1987 |
| Bartley Craig Jabbari Ltd | Real estate | 2025 |
| Barton Park Apartments Management Company Limited | Households | 2021 |
| Barton Park Management Company Limited | Households | 2021 |
| Bartonkeys Limited | Information & communication | 2014 |
| Bartrans (N.I.) Limited | Transport & logistics | 2020 |
| Barwood Construction Limited | Construction | 2013 |
| Basalt Pepper Private Limited | Wholesale & retail | 2026 |
| Base 27 Limited | Real estate | 2014 |
| Base Arcade Limited | Administrative & support | 2022 |
| Based Cafe Ltd | Hospitality | 2023 |
| Based Food Ltd | Hospitality | 2024 |
| Basedot Ltd | Information & communication | 2025 |
| Baseline Construcion Limited | Construction | 2026 |
| Bash Trading & Services Ltd | Wholesale & retail | 2020 |
| Bashforde LLP | | 2019 |
| Basic Beaches Ltd | Wholesale & retail | 2025 |
| Basic Developments Limited | Real estate | 2001 |
| Basic Element (Europe) Ltd | Wholesale & retail | 2003 |
| Basic Formations Limited | Information & communication | 2024 |
| Basil Alexandra Ltd. | Wholesale & retail | 2016 |
| Basil BEE Ltd | Information & communication | 2023 |
| Basileia Limited | Professional & scientific | 2021 |
| Bask Solar & EV UK Ltd | Energy | 2025 |
| Basketball Northern Ireland Limited | Arts & recreation | 2007 |
| Baskin Properties Ltd | Construction | 2025 |
| Basmant Trade LP | | 2018 |
| Bassj Nonde Ltd | Wholesale & retail | 2024 |