| Booksim NI Limited | Wholesale & retail | 2016 |
| Boom Clap Play Forward CIC | Arts & recreation | 2026 |
| Boom Clap Play Ltd | Information & communication | 2015 |
| Boom Interactive Ltd | Information & communication | 2010 |
| Boost Your Performance Ltd | Other services | 2020 |
| Boot Down Couriers Ltd | Transport & logistics | 2019 |
| Border PAY Limited | Financial services | 2026 |
| Borderless Goods Co. Ltd | Wholesale & retail | 2026 |
| Borderline Events Ltd | Arts & recreation | 2025 |
| Borehapy Ltd | Wholesale & retail | 2025 |
| Borehole Limited | Wholesale & retail | 2025 |
| Borempak Trade LP | | 2017 |
| Borgman Trade LP | | 2015 |
| Boric Limited | Wholesale & retail | 2025 |
| Boring Wells | Health & social care | 2009 |
| Borinity Trade LP | | 2017 |
| Bormaks Trade LP | | 2017 |
| Born Maverick Food Innovation Ltd | Professional & scientific | 2019 |
| Born to Ride Motorcycles Ltd | Wholesale & retail | 2023 |
| Borne Marketing Limited | Professional & scientific | 2020 |
| Borrowd Ltd | Information & communication | 2026 |
| Borrowdale Studio Limited | Manufacturing | 2026 |
| Borstal BOY Films Limited | Information & communication | 2026 |
| Boruitong Industrial Company Limited | Wholesale & retail | 2025 |
| Boscon Limited | Professional & scientific | 2016 |
| Boss of Property (Glasgow & NI) Ltd | Real estate | 2023 |
| Boston Belfast Limited | Hospitality | 2025 |
| Boston MFO (UK) Limited | Administrative & support | 2019 |
| Bosunstone Contracts Ltd | Construction | 2018 |
| Botanic Barbers Ltd | Other services | 2015 |
| Botanic Books Limited | Wholesale & retail | 2025 |
| Botanic Consultancy Limited | Professional & scientific | 2023 |
| Botanic Development Company Ltd | Construction | 2017 |
| Botanic Foods (N.I.) Limited | Hospitality | 2019 |
| Botanic Link Limited | Real estate | 2015 |
| Botanic Pubs Limited | Hospitality | 2009 |
| Botanic Restaurant Limited | Hospitality | 2019 |
| Botanic Stores Limited | Wholesale & retail | 2016 |
| Botanic Thai Massage Ltd | Health & social care | 2024 |
| Botanic Way Limited | Hospitality | 2016 |
| Botanica International Limited | Manufacturing | 2005 |
| Botanica Ireland Ltd | Manufacturing | 2020 |
| Botanica Limited | Manufacturing | 2023 |
| Botaniquo Ltd | Manufacturing | 2025 |
| Both Barrels Comedy Ltd | Administrative & support | 2022 |
| Bottle Green Drinks Company Limited | Manufacturing | 2011 |
| Bottle Green Property Ltd | Real estate | 2025 |
| Bottle Top Media Ltd | Information & communication | 2011 |
| Bottlebrush Limited | Wholesale & retail | 2025 |
| Botto Trading Limited | Wholesale & retail | 2021 |
| Boucher Auto Centre Ltd | Wholesale & retail | 2024 |
| Boucher Construction & Shopfitting Limited | Construction | 2025 |
| Boucher Deli Co Ltd | Hospitality | 2020 |
| Boucher Properties Limited | Real estate | 1976 |
| Boucherwood Limited | Real estate | 2003 |
| Boujeet Ltd | Wholesale & retail | 2025 |
| Boulder Media UK Limited | Information & communication | 2024 |
| Boulder World Limited | Arts & recreation | 2013 |
| Boulevard Park Management Company Limited | Extraterritorial | 2005 |
| Bounce Culture C.I.C. | Education | 2012 |
| Bounce KD Ltd | Education | 2014 |
| Bound (N.I.) Limited | Wholesale & retail | 2019 |
| Boundary Belfast Ltd | Arts & recreation | 2022 |
| Boundary Brewing Running Club CIC | Arts & recreation | 2024 |
| Boundary Compete Ltd | Arts & recreation | 2022 |
| Boundless Provision Ltd | Professional & scientific | 2025 |
| Boundless Shanmei Ltd | Wholesale & retail | 2024 |
| Boutique NI Accommodation Limited | Hospitality | 2024 |
| BOW Estates Ltd | Real estate | 2000 |
| BOW Lane Ltd | Real estate | 2025 |
| BOW Street Mall Limited | Real estate | 2001 |
| Bowal Rays Limited | Wholesale & retail | 2025 |
| Bowden Corporation Ltd | Professional & scientific | 2020 |
| Bowden Property Group Ltd | Professional & scientific | 2022 |
| Bowden Robertson Developments Ltd | Construction | 2020 |
| Bowin Industry Limited | Wholesale & retail | 2025 |
| Bowman Lift Installations Ltd | Construction | 2022 |
| Bowsaw Bourbon Holdco Limited | Financial services | 2025 |
| Bowsaw Bourbon Limited | Extraterritorial | 2018 |
| Box Displays Investments Limited | Real estate | 2019 |
| Boycatty Ltd | Wholesale & retail | 2025 |
| Boycott Limited | Wholesale & retail | 2025 |
| Boyd Construction Ltd | Construction | 2019 |
| Boyd Electrical Contractors Ltd | Construction | 2026 |
| Boydbury Ltd | Real estate | 2024 |
| Boyds of Ballymoney Limited | Hospitality | 2017 |
| Boylans Irish Whiskey Limited | Administrative & support | 2017 |
| Boyne Enterprises C.I.C. | Construction | 2016 |
| Boys & Girls Clubs (NI) | Education | 2012 |
| BP Commercials Limited | Wholesale & retail | 2018 |
| BP Concrete Flooring Limited | Extraterritorial | 1973 |
| BP Electrics Ltd | Construction | 2007 |
| BP Furniture Ltd | Wholesale & retail | 2023 |
| BP Gibson Group Limited | Construction | 2021 |
| BPC Ceilings Limited | Construction | 2017 |
| BPC Leisure Group Limited | Administrative & support | 2024 |
| BPJ Fitout Limited | Construction | 2016 |
| BPK Property Limited | Extraterritorial | 2014 |
| BPM Medical Limited | Health & social care | 2021 |
| BPM Safety Services LLP | | 2017 |