| Blast XSX Co., Ltd | Wholesale & retail | 2024 |
| Blaze Tech Studios Limited | Extraterritorial | 2024 |
| Blendmart Ltd | Wholesale & retail | 2025 |
| Blenheim Management Solutions Limited | Professional & scientific | 2022 |
| Blenheim Medico-Legal Services Limited | Health & social care | 2011 |
| Blethers (N.I.) Ltd | Hospitality | 2016 |
| Blhair Limited | Other services | 2023 |
| Blick Shared Studios | Arts & recreation | 2007 |
| Blinc Electrical Limited | Construction | 2023 |
| Blind Centre for Northern Ireland-The | Health & social care | 1987 |
| Blingblink Ltd | Wholesale & retail | 2024 |
| Blink Parties Ltd | Administrative & support | 2024 |
| Blinkout LLP | | 2024 |
| Blinks Beauty Ltd | Wholesale & retail | 2023 |
| Blinne Court Management Co Ltd | Households | 2017 |
| Bliss Business Link Ltd | Transport & logistics | 2024 |
| BLK Motors Ltd | Wholesale & retail | 2024 |
| Bllxgh Limited | Wholesale & retail | 2024 |
| Blncgr Ltd | Wholesale & retail | 2024 |
| Blockchain First Ltd | Information & communication | 2018 |
| Blond Housing Limited | Real estate | 2015 |
| Bloom Hongbin Ltd | Wholesale & retail | 2024 |
| Bloom Technology Ltd | Professional & scientific | 2026 |
| Bloomfield Auctions Ltd | Real estate | 2014 |
| Bloomfield Avenue Developments Limited | Real estate | 2018 |
| Bloomfield Care Homes Ltd | Health & social care | 2017 |
| Bloomfield Corporate Consultancy Limited | Financial services | 2012 |
| Bloomfield Menswear Limited | Wholesale & retail | 2017 |
| Bloomfield Palace Ltd | Hospitality | 2019 |
| Bloomfield Place Management Limited | Households | 2006 |
| BLOOMFIELD52 Management Company Limited | Real estate | 2018 |
| Bloomfields Care Management Limited | Administrative & support | 2021 |
| Blopeur Limited | Information & communication | 2013 |
| Blossom Daycare Ltd | Health & social care | 2021 |
| Blossom Entertainment Limited | Wholesale & retail | 2017 |
| Blosum LP | | 2022 |
| Blow Moulding Technologies Ltd | Manufacturing | 2011 |
| BLS Group Ltd | Real estate | 2026 |
| BLS Investments Limited | Financial services | 2019 |
| BLU Nutrition Limited | Wholesale & retail | 2024 |
| BLU Restaurant Ltd | Hospitality | 2014 |
| BLU Zebra Ltd | Professional & scientific | 2006 |
| Bluda Index Ltd | Information & communication | 2017 |
| Blue Angels Motorcycle Club Ltd | Other services | 2022 |
| Blue Art Group Ltd | Wholesale & retail | 2024 |
| Blue Bone Imports Limited | Wholesale & retail | 2006 |
| Blue Bowl (Wind) Limited | Professional & scientific | 2013 |
| Blue Bowl Horizon (Developments) Limited | Professional & scientific | 2014 |
| Blue Bowl Investments Limited | Financial services | 2012 |
| Blue Box Strategies Ltd | Professional & scientific | 2017 |
| Blue Bridge Ltd | Other services | 2008 |
| Blue Burger Restaurants Ltd | Hospitality | 2021 |
| Blue Chicago Burgers Ltd | Hospitality | 2014 |
| Blue Chicago Grill Ltd | Hospitality | 2017 |
| Blue Cube Bespoke Limited | Information & communication | 2006 |
| Blue Diamond Events Limited | Information & communication | 2025 |
| Blue Diamond Global Health Limited | Health & social care | 2024 |
| Blue Diamond Jewellery E-Commerce Limited | Wholesale & retail | 2024 |
| Blue Door Seafoods Ltd | Manufacturing | 2025 |
| Blue Dragon 321 Ltd | Wholesale & retail | 2022 |
| Blue Duck Ventures Limited | Information & communication | 2024 |
| Blue Emerald Properties Ltd | Real estate | 2012 |
| Blue EYE Highway Ltd | Administrative & support | 2020 |
| Blue Eyed Properties Limited | Administrative & support | 2022 |
| Blue Green Planet UK Limited | Manufacturing | 2010 |
| Blue Horizon (Ballycorr) Limited | Construction | 2021 |
| Blue Horizon (Westmount) Limited | Construction | 2014 |
| Blue Horizon Financial Ltd | Professional & scientific | 2003 |
| Blue Karst Limited | Real estate | 2014 |
| Blue Moon Property Claims Ltd | Financial services | 2018 |
| Blue Orbit Trade Ltd | Wholesale & retail | 2025 |
| Blue Pool PR Ltd | Administrative & support | 2025 |
| Blue Rose Living Ltd | Wholesale & retail | 2020 |
| Blue Sail Technologies Ltd | Manufacturing | 2024 |
| Blue Sky Energy Ltd | Professional & scientific | 2024 |
| Blue Sky Thai Massage Ltd | Health & social care | 2024 |
| Blue Sky Training Ltd | Education | 2007 |
| Blue Square House Ltd | Real estate | 2023 |
| Blue Titans Limited | Real estate | 2013 |
| Blue Village Limited | Real estate | 2010 |
| Blue Whale Creative Ltd | Professional & scientific | 2024 |
| Blue Zinc IT Ltd | Information & communication | 2002 |
| Bluearc Mechanical Ltd | Construction | 2024 |
| Bluebell Bakery Ltd | Wholesale & retail | 2015 |
| Bluebell Hill Limited | Hospitality | 2011 |
| Bluebelles Catering Ltd | Hospitality | 2024 |
| Blueberry PH Limited | Wholesale & retail | 2015 |
| Blueeyes Healthcare Ltd | Health & social care | 2021 |
| Bluefield Houseboats Ltd | Manufacturing | 2009 |
| Bluefin IT Ltd | Information & communication | 2025 |
| Bluegator Creative Ltd | Information & communication | 2012 |
| Bluehill Lettings Ltd | Real estate | 2026 |
| Bluehouse Development Limited | Construction | 1998 |
| Bluemoon Dayi Ltd | Wholesale & retail | 2024 |
| Bluemountain Liang Ltd | Wholesale & retail | 2024 |
| Bluepaper Limited | Information & communication | 2026 |
| Blueshore Consulting Ltd | Information & communication | 2017 |
| Bluesky Film & Documentary Ltd | Information & communication | 2024 |
| Bluesky Video Marketing Ltd | Information & communication | 2018 |
| Bluesona Limited | Manufacturing | 2017 |