| Black Dog (Holdings) Ltd | Professional & scientific | 2013 |
| Black DOT Social Ltd | Professional & scientific | 2019 |
| Black EYE Bens Ltd | Hospitality | 2023 |
| Black Fabulous UK CIC | Information & communication | 2021 |
| Black Forest Developments Ltd | Construction | 2021 |
| Black Futures CIC | Education | 2025 |
| Black Garlic Events Ltd | Hospitality | 2025 |
| Black Girl Confessions Ltd | Information & communication | 2025 |
| Black Girls Hike UK C.I.C. | Other services | 2020 |
| Black Gold 15 Ltd | Construction | 2024 |
| Black Gold Arts | Education | 2018 |
| Black Grove Ltd | Wholesale & retail | 2024 |
| Black Hawk Nutrition Ltd | Wholesale & retail | 2021 |
| Black Hawk Professionals Limited | Professional & scientific | 2015 |
| Black Horse Cafe Ltd | Hospitality | 2024 |
| Black Horse Property Investments Ltd | Real estate | 2023 |
| Black Hydra Investments Limited | Financial services | 2014 |
| Black Ice CPD Limited | Energy | 2016 |
| Black Ivory for General Contracting Ltd | Construction | 2025 |
| Black Knight Capital Limited | Financial services | 2026 |
| Black Label Digital Ltd | Professional & scientific | 2026 |
| Black Label Grooming Holdings Limited | Wholesale & retail | 2017 |
| Black Lace Events Ltd | Arts & recreation | 2023 |
| Black Leather Limited | Other services | 2024 |
| Black Lights Projects CIC | Arts & recreation | 2023 |
| Black Line for Investment Ltd | Other services | 2024 |
| Black Lynx Protection Ltd | Administrative & support | 2026 |
| Black Magix Limited | Arts & recreation | 2025 |
| Black Milk Cereal Ltd | Wholesale & retail | 2019 |
| Black Muse Limited | Other services | 2025 |
| Black Operations Security Ltd | Administrative & support | 2014 |
| Black OR White Limited | Construction | 2006 |
| Black Orchid Media Group Ltd | Information & communication | 2024 |
| Black Path Properties Limited | Professional & scientific | 2024 |
| Black Pearl Tour Production Ltd | Arts & recreation | 2021 |
| Black Pigeon Mobile Technology Limited | Wholesale & retail | 2013 |
| Black Rain Coffee Shop Ltd | Hospitality | 2022 |
| Black Rock BTC Ltd | Extraterritorial | 2025 |
| Black Rock Private Ltd | Wholesale & retail | 2025 |
| Black Rose Enterprise Limited | Other services | 2024 |
| Black Rose Spirits Ltd | Hospitality | 2015 |
| Black Salt Kitchen Ltd | Hospitality | 2024 |
| Black Solicitors Network Limited | Professional & scientific | 2003 |
| Black Stars Restaurant Limited | Hospitality | 2025 |
| Black Stone Digital Hub Ltd | Information & communication | 2025 |
| Black Stone Farms Development Ltd | Agriculture & fishing | 2025 |
| Black Stone Medical Limited | Health & social care | 2022 |
| Black Street Property Limited | Real estate | 2021 |
| Black Street Property Management Limited | Real estate | 2022 |
| Black Swan 29 Ltd | Professional & scientific | 2023 |
| Black Tech Expo Limited | Information & communication | 2025 |
| Black Tick (BLK - TCK) Limited | Information & communication | 2024 |
| Black Tide Industries Limited | Wholesale & retail | 2026 |
| Black Tiger Distribution Ltd | Health & social care | 2019 |
| Black TOD Ltd | Wholesale & retail | 2025 |
| Black Top Cars Ltd | Transport & logistics | 2024 |
| Black Tower Renovations Ltd | Real estate | 2021 |
| Black Warehouses Co Ltd | Wholesale & retail | 2025 |
| Black Wolf Coffee Company Ltd | Manufacturing | 2021 |
| Black's Gardening and Grounds-Keeping Services Ltd | Administrative & support | 2024 |
| Blackayard Recordings Limited | Wholesale & retail | 2022 |
| Blackayard Studio Limited | Manufacturing | 2022 |
| Blackbeard Academy Group Limited | Arts & recreation | 2026 |
| Blackbee Builders Limited | Construction | 2018 |
| Blackberry Vehicle Solutions Limited | Wholesale & retail | 2008 |
| Blackbird Five Partnership LLP | | 2013 |
| Blackbirdz Ltd | Wholesale & retail | 2024 |
| Blackbond Logistics Ltd | Transport & logistics | 2025 |
| Blackboy Promotions Limited | Administrative & support | 2014 |
| Blackbull Logistics Limited | Transport & logistics | 2025 |
| Blackburn & Roberts Manufacturing Ltd | Manufacturing | 2014 |
| Blackburn Hair Loss Clinic Ltd | Other services | 2023 |
| Blackburn Healthcare Ltd | Health & social care | 2009 |
| Blackburn Lodge Property Management (Didsbury) Limited | Households | 2004 |
| Blackcarr Mini Market Ltd | Wholesale & retail | 2024 |
| Blackcarr Services Ltd | Information & communication | 2011 |
| Blackcrest Telecom Surveys Ltd | Information & communication | 2026 |
| Blackdog Bars Limited | Hospitality | 2018 |
| Blackett House Ltd | Real estate | 2023 |
| Blackfield Capital Ltd | Financial services | 2026 |
| Blackfields Court Management Company Limited | Households | 1982 |
| Blackflash Logistics Limited | Transport & logistics | 2021 |
| Blackford Estates Holdings Ltd | Real estate | 2026 |
| Blackford Estates Ltd | Real estate | 2022 |
| Blackframe Limited | Wholesale & retail | 2010 |
| Blackfriars Construction Limited | Construction | 2019 |
| Blackfriars F.C Ltd | Arts & recreation | 2024 |
| Blackfriars ST Ltd. | Construction | 2014 |
| Blackhawk Properties Limited | Real estate | 2007 |
| Blackjack Bar (Altrincham) Limited | Hospitality | 2014 |
| Blackjack Bar (Mackie Mayor) Limited | Wholesale & retail | 2017 |
| Blackjack Bar (NQ) Limited | Hospitality | 2015 |
| Blackjack Beers (Holdings) Limited | Financial services | 2019 |
| Blackjack Beers Limited | Manufacturing | 2011 |
| Blackk Hawk Production Limited | Manufacturing | 2020 |
| Blacklane Mini Market Ltd | Wholesale & retail | 2026 |
| Blackledge Services Ltd | Wholesale & retail | 2022 |
| Blackley 2010 Limited | Manufacturing | 2010 |
| Blackley Carpets Limited | Wholesale & retail | 2010 |
| Blackley Community Hub CIC | Education | 2025 |