| B & D Associates Limited | Wholesale & retail | 1997 |
| B & D Property Services Limited | Professional & scientific | 2002 |
| B & F Global Ltd | Extraterritorial | 2026 |
| B & J Agencies Ltd | Wholesale & retail | 1995 |
| B & J International Trading Company Ltd | Wholesale & retail | 2018 |
| B & L Dental & Property Services Limited | Real estate | 1985 |
| B & S Labels Ltd | Manufacturing | 2016 |
| B and E Contracts Ltd | Wholesale & retail | 2025 |
| B Braun Medical (N.I.) Limited | | 1991 |
| B C D Partnership Limited | Professional & scientific | 2003 |
| B Cabs Limited | Transport & logistics | 2016 |
| B D Garments Ltd | Manufacturing | 2023 |
| B F House Limited | Hospitality | 2016 |
| B G Foods (Belfast) Ltd | Hospitality | 2023 |
| B Loves Co Limited | Manufacturing | 2025 |
| B M Electrical Wholesale Limited | Wholesale & retail | 2003 |
| B News (NI) Limited | Professional & scientific | 2013 |
| B Price Services Ltd | Financial services | 2022 |
| B R Construction Limited | Construction | 2001 |
| B the Label Ltd | Wholesale & retail | 2021 |
| B W Motorsport Ltd | Arts & recreation | 2007 |
| B Wahtglass Ltd | Wholesale & retail | 2024 |
| B Z Flow Ltd | Wholesale & retail | 2025 |
| B&B Hospitality Services Ltd | Hospitality | 2025 |
| B&Bg Investments Limited | Real estate | 2020 |
| B&L Retail Limited | Wholesale & retail | 2023 |
| B&M Glenville Ltd | Real estate | 2024 |
| B&M Mcks Limited | Hospitality | 2024 |
| B&N M K Holdings Limited | Professional & scientific | 2025 |
| B&R Catering Ltd | Hospitality | 2024 |
| B'S Mini Mart Ltd | Wholesale & retail | 2024 |
| B-Mac Communications Ltd | Construction | 2014 |
| B-Mac Housing Limited | Real estate | 2022 |
| B-Mac Mechanical Holding Ltd | Financial services | 2024 |
| B-Secur Limited | Professional & scientific | 1996 |
| B. E. Pearce Ltd. | Construction | 2025 |
| B. Mcclinton & Sons (Haulage) Limited | Transport & logistics | 2015 |
| B. Mcnamee & Co. Ltd | Wholesale & retail | 1997 |
| B. Robinson Investments Limited | Hospitality | 2016 |
| B.A Properties Ltd | Real estate | 2021 |
| B.A.Shaw Contractors Limited | Construction | 1976 |
| B.Aesthetics Ltd | Health & social care | 2017 |
| B.D.A. (Property Projects) Limited | Administrative & support | 1984 |
| B.D.A. Venue Management Limited | Real estate | 2025 |
| B.J.F International Ltd | Transport & logistics | 2019 |
| B.J.G.D Limited | Health & social care | 2021 |
| B.L. Group Limited | Professional & scientific | 2019 |
| B.L. Refrigeration & Air Conditioning Limited | Construction | 1978 |
| B.M.C. Fruit & Produce Ltd. | Extraterritorial | 1985 |
| B.M.C.A. Properties Ltd | Real estate | 2024 |
| B.N.E. Electronics Limited | Information & communication | 1980 |
| B.R. Nursery Wholesale | Wholesale & retail | 1998 |
| B.Robinson Consulting Ltd | Information & communication | 2013 |
| B.S. Holdings Limited | Construction | 2000 |
| B10HUB Limited | Information & communication | 2024 |
| B2B Communications Ltd | Information & communication | 2019 |
| B2L Developments (NI) Limited | Real estate | 2014 |
| B2T Ventures Limited | Information & communication | 2018 |
| B3N Recovery Limited | Transport & logistics | 2025 |
| B4B Group Holdings Ltd | Information & communication | 2017 |
| B4B Group Ltd | Information & communication | 2016 |
| B4B Renewables Holdco Ltd | Professional & scientific | 2023 |
| B4B Renewables Ltd | Construction | 2010 |
| B4B Telecoms Group Limited | Information & communication | 2020 |
| B4B Telecoms Ltd | Information & communication | 2013 |
| B8C Investments Limited | Real estate | 2025 |
| BA Care Collective Ltd | Health & social care | 2026 |
| BA Hotels Ltd | Hospitality | 2022 |
| BA Kamilla Ltd | Health & social care | 2022 |
| BA Quarries Ltd | Mining & quarrying | 2017 |
| Baan Thai (Antrim) Limited | Hospitality | 2022 |
| Babaisp Ltd | Wholesale & retail | 2025 |
| Babble Belfast Ltd | Professional & scientific | 2020 |
| Baby Bearderefail Ltd | Wholesale & retail | 2025 |
| Baby Bedibies (NI) Limited | Wholesale & retail | 2026 |
| Baby Sea Limited | Wholesale & retail | 2024 |
| Babyg Ltd | Wholesale & retail | 2022 |
| Babyjialeds Limited | Wholesale & retail | 2023 |
| BAC Holdco Limited | Professional & scientific | 2024 |
| Baca Construction Ltd | Construction | 2021 |
| Bacchin Marco Ltd | Wholesale & retail | 2025 |
| Back on Track Pilates NI Ltd | Other services | 2020 |
| Back to Health Chiropractic Clinics Limited | Health & social care | 1997 |
| Back to Health Wellness Centres Ltd | Administrative & support | 2002 |
| Backley Capital LP | | 2015 |
| Backlower Construction Ltd | Construction | 2025 |
| Backstop Consulting Limited | Professional & scientific | 2013 |
| Backyard Bites Ltd | Hospitality | 2026 |
| BAD Book Press Ltd | Information & communication | 2025 |
| BAD Bridgets Limited | Information & communication | 2025 |
| BAD Day Pictures Ltd | Information & communication | 2016 |
| BAD Girl Barre Limited | Education | 2019 |
| Badgeco Ltd | Manufacturing | 2025 |
| Badlands Films Limited | Information & communication | 2021 |
| Baffin Limited | Wholesale & retail | 2025 |
| BAG of Bees Ltd | Professional & scientific | 2011 |
| Bagel Limited | Professional & scientific | 2016 |
| Bagold Limited | Agriculture & fishing | 2009 |
| Baiang Limited | Other services | 2024 |
| Bailey Management LLP | | 2007 |