| Black Country Developments Limited | Real estate | 1992 |
| Black Country Kitchens Limited | Hospitality | 2008 |
| Black Country Marine Limited | Manufacturing | 2026 |
| Black Country Take Away Ltd | Hospitality | 2025 |
| Black Country Traffic Management Ltd | Construction | 2023 |
| Black Country Tyres and Recovery Services Limited | Wholesale & retail | 2023 |
| Black Crown Group Limited | Financial services | 2023 |
| Black Cube Enterprise Ltd | Financial services | 2025 |
| Black Cube Trading Ltd | Health & social care | 2026 |
| Black Diamonds Creations CIC | Arts & recreation | 2024 |
| Black Emerald Properties Limited | Real estate | 2025 |
| Black EYE Collective Ltd | Financial services | 2019 |
| Black EYE Labs Ltd | Wholesale & retail | 2017 |
| Black EYE Property Ltd | Real estate | 2024 |
| Black EYE Ventures Ltd | Financial services | 2025 |
| Black Family Practitioners Network (Bfpn) CIC | Other services | 2024 |
| Black Gold Real Estate Ltd | Real estate | 2019 |
| Black Heritage Support Service C.I.C. | Other services | 2020 |
| Black Heritage Walks Network CIC | Education | 2020 |
| Black Horse Homes Holding Limited | Financial services | 2025 |
| Black Horse Homes Limited | Construction | 2007 |
| Black I Limited | Professional & scientific | 1997 |
| Black Label Stays Ltd | Real estate | 2026 |
| Black Lion Collective Ltd | Administrative & support | 2026 |
| Black Mango Capital UK Ltd | Financial services | 2014 |
| Black Mango Investments (Sutton) Ltd | Real estate | 2022 |
| Black Mango Investments UK Ltd | Real estate | 2019 |
| Black Market Barber Company Limited | Administrative & support | 2016 |
| Black Maxx Ltd | Wholesale & retail | 2024 |
| Black Mountain Bikes Limited | Extraterritorial | 2017 |
| Black Munee Limited | Information & communication | 2021 |
| Black Oak & Sons Limited | Real estate | 2025 |
| Black Oak Realty Group Ltd | Real estate | 2021 |
| Black Palm Ltd | Health & social care | 2015 |
| Black Pear Environmental Ltd | Water & waste | 2014 |
| Black Pearl Medical Ltd | Health & social care | 2019 |
| Black Pepper Crew Limited | Administrative & support | 2024 |
| Black Psychotherapy Community CIC | Health & social care | 2025 |
| Black Psychotherapy Ltd | Health & social care | 2025 |
| Black Rock Property Development Ltd | Real estate | 2017 |
| Black Sail Express Limited | Transport & logistics | 2026 |
| Black Shogun Limited | Wholesale & retail | 2026 |
| Black Space Technology Limited | Information & communication | 2018 |
| Black Square Property Ltd | Real estate | 2020 |
| Black Star Diva Ltd | Manufacturing | 2020 |
| Black Star Kitchen Ltd. | Hospitality | 2017 |
| Black Stone XS International Limited | Administrative & support | 2019 |
| Black Studies Research Impact Diaspora and Global Education Centre CIC | Education | 2026 |
| Black Swan Corporate Developments Limited | Real estate | 2021 |
| Black Swan Residence Ltd | Households | 2023 |
| Black Thread Cafe Ltd | Hospitality | 2026 |
| Black Tide Operations Ltd | Professional & scientific | 2026 |
| Black Tower Security & K9 Ltd | Administrative & support | 2018 |
| Black Trading Forex Ltd | Information & communication | 2020 |
| Black Voices Projects Ltd | Administrative & support | 2016 |
| Black Voices UK Ltd | Administrative & support | 2013 |
| Black Widow Hospitality Limited | Hospitality | 2026 |
| Black Widow Martial Arts Ltd | Arts & recreation | 2025 |
| Blackajack Productions Ltd | Arts & recreation | 2014 |
| Blackat Fitness Clubs Ltd | Arts & recreation | 2017 |
| Blackberry Design Limited | Professional & scientific | 2010 |
| Blackberry Lane Property Limited | Real estate | 2023 |
| Blackbird One Limited | Hospitality | 2023 |
| Blackbird Performance Ltd | Manufacturing | 2025 |
| Blackbird Trading Bham Ltd | Hospitality | 2023 |
| Blackburn Desserts Ltd | Hospitality | 2026 |
| Blackcat Comms Limited | Construction | 2005 |
| Blackcurve Solutions Limited | Information & communication | 2016 |
| Blackfish Limited | Wholesale & retail | 2026 |
| Blackford Enterprise Ltd | Real estate | 2023 |
| Blackfriars Law Limited | Professional & scientific | 2018 |
| Blackgate Accountancy Ltd | Professional & scientific | 2025 |
| Blackhams and Conroy Limited | Professional & scientific | 2025 |
| Blackhill Motors Ltd | Wholesale & retail | 2026 |
| Blackhood Developments Limited | Administrative & support | 2016 |
| Blackhorse Hub Ltd | Wholesale & retail | 2024 |
| Blackhorse Law Ltd. | Professional & scientific | 2023 |
| Blackink Trades Ltd | Wholesale & retail | 2023 |
| Blackjacks Desserts Ltd | Hospitality | 2021 |
| Blackleaf Solutions Limited | Information & communication | 2014 |
| Blackleyskitchens Ltd | Wholesale & retail | 2019 |
| Blackline Cars Ltd | Wholesale & retail | 2026 |
| Blackline International Limited | Information & communication | 2008 |
| Blackline Media Limited | Information & communication | 2008 |
| Blacklist Customs Ltd | Wholesale & retail | 2026 |
| Blackmark Limited | Manufacturing | 2003 |
| Blackmark Services (Walsall) Limited | Manufacturing | 2012 |
| Blackmoor Capital Ltd | Wholesale & retail | 2026 |
| Blackox Ventures Limited | Financial services | 2021 |
| Blackpole Trading Estate (1978) Limited | Real estate | 1957 |
| Blackrock Accountants Limited | Professional & scientific | 2026 |
| Blackrock Minerals Ltd | Mining & quarrying | 2025 |
| Blackrock Property Management Limited | Real estate | 2022 |
| Blackrock Transport Limited | Transport & logistics | 2026 |
| Blackshaw Group Limited | Professional & scientific | 2025 |
| Blackspade Group Ltd | Real estate | 2026 |
| Blackstar Wealth Management Ltd | Financial services | 2008 |
| Blackstarstudio Ltd | Professional & scientific | 2023 |
| Blackstone Bakes Ltd | Hospitality | 2025 |
| Blackstone Capital (Intl) Limited | Real estate | 2018 |