| BFL Engineering Ltd | Professional & scientific | 2020 |
| Bhinder Holdings Ltd | Wholesale & retail | 2026 |
| BIC Decor Ltd | Construction | 2023 |
| Big Foot Catering Limited | Manufacturing | 1993 |
| Big Mouth Candy Ltd | Wholesale & retail | 2023 |
| Big White Van Ltd | Transport & logistics | 2011 |
| Bill Higham Marine Ltd | Manufacturing | 2010 |
| Billy’S Hair Station Ltd | Other services | 2026 |
| Birch Lake Investments Limited | Financial services | 2019 |
| Bird of Paradise Ministries in Rwanda | Health & social care | 2011 |
| Bird Surveyors Ltd | Professional & scientific | 2014 |
| Birds & Words (UK) Limited | Wholesale & retail | 2011 |
| Bitterwen Ltd | Wholesale & retail | 2024 |
| BL Finance (NI) Limited | Financial services | 2007 |
| Black Label Vehicle Wraps Ltd | Manufacturing | 2025 |
| Blackabbey Consulting Ltd | Professional & scientific | 2014 |
| Blackball Ltd | Professional & scientific | 2006 |
| Blackham Electrical Limited | Construction | 2011 |
| Blackhorse Lane Student Limited | Construction | 2013 |
| Blacklock Group Limited | Energy | 2023 |
| Blackthorn Horizon Ltd | Professional & scientific | 2026 |
| Blackthorn Strong Ltd | Education | 2023 |
| Blackwood Golf Management Ltd | Arts & recreation | 2015 |
| Blackwood Management Company Limited | Extraterritorial | 2001 |
| Blackwood Newtownards Management Company Limited | Real estate | 2014 |
| Blaiddwen Services Limited | Professional & scientific | 2023 |
| Blas LON LAS CIC | Hospitality | 2024 |
| Blessed to Bless Limited | Health & social care | 2023 |
| Blizzard Protection Systems Limited | Manufacturing | 2000 |
| BLM Design Ltd | Professional & scientific | 2018 |
| Bloomfield Male Grooming Ltd | Other services | 2026 |
| Bloomfield Manor Management Company Limited | Extraterritorial | 1999 |
| Bloomfield Specsavers Hearcare Limited | Wholesale & retail | 2017 |
| Bloomfield Specsavers Limited | Wholesale & retail | 1995 |
| Bloomfield Visionplus Limited | Wholesale & retail | 1995 |
| Blooms OS Ltd | Wholesale & retail | 2025 |
| Bloyeni Limited | Information & communication | 2012 |
| BLU Buddha Company Ltd | Hospitality | 2014 |
| Blue Skies Ahead Community Interest Company | Hospitality | 2016 |
| Blue Sky Cafe CYF | Hospitality | 2019 |
| Blue Tree Logistics Ltd | Construction | 2018 |
| Blueprint Ministries NI | Other services | 2024 |
| BM Catering Limited | Hospitality | 2017 |
| BMI Systems Limited | Manufacturing | 2024 |
| Bnns Properties Ltd | Real estate | 2025 |
| Bodlondeb Estate Ltd | Real estate | 2026 |
| Body Success Ltd | Arts & recreation | 2014 |
| Boom! Inc | Arts & recreation | 2016 |
| Boppel Ltd | Information & communication | 2026 |
| Born Maverick Interactive Ltd | Arts & recreation | 2024 |
| Boujee Brands Ltd | Hospitality | 2021 |
| Boyd Electrical Services Limited | Construction | 2007 |
| BP Sports Ltd | Arts & recreation | 2018 |
| Bpvp Ltd | Professional & scientific | 2022 |
| Brabc Ltd | Information & communication | 2025 |
| Bradben Ltd | Real estate | 2025 |
| Bradley Belfast Limited | Professional & scientific | 2015 |
| Braidview Trading Limited | Hospitality | 2004 |
| Brainbox X Ltd | Professional & scientific | 2021 |
| Brandblack Ltd. | Professional & scientific | 2013 |
| Break Free Ltd | Professional & scientific | 2021 |
| Breakhouse Sports Ltd | Arts & recreation | 2024 |
| Breen Short Stays Ltd | Real estate | 2025 |
| Brian FOX Ltd. | Wholesale & retail | 2011 |
| Brian Kelly Consulting Ltd | Financial services | 2013 |
| Brickwork Creative Ltd | Professional & scientific | 2024 |
| Bridge 22 Management (NO 2) Co Ltd | Real estate | 2013 |
| Bridge Road Bath Limited | Construction | 2020 |
| Bridge Street Student Limited | Construction | 2015 |
| Bridges Garage Limited | Real estate | 2005 |
| Bridle Path Watford Limited | Construction | 2022 |
| Briggs Accountancy Ltd | Professional & scientific | 2002 |
| Briggs Apartments Limited-The | Households | 1998 |
| Bright Sparks Montessori Preschool Limited | Education | 2015 |
| Brithdir Mawr Cyfyngedig | Hospitality | 2020 |
| BRN Building Services Limited | Financial services | 2019 |
| Broadleaf Carpentry Ltd | Manufacturing | 2017 |
| Broadway Catering Ltd | Hospitality | 2023 |
| Bron Hwfa Management Limited | Households | 2022 |
| Brook Lane Block B Property Management Limited | Extraterritorial | 2021 |
| Brook Lane Property Management Limited | Extraterritorial | 2021 |
| Brooklands Ballyholme Management Company Limited | Households | 2020 |
| Brookwell Garden Rooms Ltd | Construction | 2017 |
| Broomthomaswilliam Ltd | Agriculture & fishing | 2025 |
| Brotherston Removals & Storage Ltd | Transport & logistics | 2020 |
| Brunomakes Ltd | Administrative & support | 2026 |
| Brunswick Lane Management Company Limited | Households | 2007 |
| Brunswick Manor Limited | Real estate | 1966 |
| Brunswick Productions Ltd | Administrative & support | 2023 |
| Brunswick Rentals Limited | Real estate | 2025 |
| Bryan Boyd Ltd | Hospitality | 2016 |
| Bryansburn Management Ltd | Extraterritorial | 2004 |
| Bryansglen Apartments Limited | Households | 1987 |
| Bryce Amps Limited | Manufacturing | 2007 |
| Bryn Adda Phase 2 Management Company Limited | Water & waste | 2010 |
| Bryn Gwyn Management Company Limited | Real estate | 2015 |
| Bryn Williams Mountaineering Limited | Arts & recreation | 2020 |
| Bryn-Y-Coed Flats (Management) Limited | Households | 1978 |
| Brynmor Park Management Ltd | Real estate | 2023 |
| BSS Automation Limited | Manufacturing | 2022 |