| Bhava Company Ltd | Arts & recreation | 2025 |
| BHC Lettings Limited | Real estate | 2021 |
| Big Bay Properties Ltd | Hospitality | 2025 |
| Big Belly Rude Boy'Z Ltd | Hospitality | 2024 |
| Big Crocodile Ltd | Wholesale & retail | 2011 |
| Big Discoveries Ltd | Health & social care | 2016 |
| Big Dog Builders Ltd | Construction | 2023 |
| Big Dog Research Limited | Professional & scientific | 2025 |
| Big FAT Wedding Expo Limited | Administrative & support | 2025 |
| Big Hospitality Ltd | Hospitality | 2021 |
| Big Picture LAB Consulting Limited | Professional & scientific | 2026 |
| Big South Bullys Ltd | Agriculture & fishing | 2020 |
| Big Trouble Films Limited | Information & communication | 2016 |
| Biggie Smalls Ltd | Wholesale & retail | 2021 |
| Bighart Ltd | Wholesale & retail | 2022 |
| Bigneat Limited | Manufacturing | 1973 |
| Bike IT Group Limited | Financial services | 2026 |
| Billy Manning Limited | Arts & recreation | 1961 |
| Binexus Ltd | Professional & scientific | 2024 |
| Binlicked Ltd | Administrative & support | 2025 |
| Bio-Bubble Technologies Limited | Water & waste | 2009 |
| Bird Medical Services Limited | Health & social care | 2018 |
| Bird Services (Horndean) Ltd | Construction | 2019 |
| Bird’S EYE View Studio Ltd | Administrative & support | 2024 |
| Birkett Consulting Ltd | Professional & scientific | 2025 |
| Birnie & Hobkirk Medical Limited | Health & social care | 2020 |
| Bishop Brothers (Hampshire) Limited | Real estate | 1973 |
| Bishop Security Consultancy Limited | Administrative & support | 2017 |
| Bisk Business Development Ltd | Information & communication | 2024 |
| Bisley Limited | Professional & scientific | 1973 |
| Bitbranch Ltd | Information & communication | 2023 |
| Bits & Bytes IT Ltd | Information & communication | 2020 |
| Bitstech Ltd | Information & communication | 2018 |
| BIZ Essentials Ltd | Administrative & support | 2022 |
| BJM Rentals Ltd | Real estate | 2024 |
| BL Transport and Logistics Ltd | Transport & logistics | 2022 |
| Black & Red Accountkeeping Solutions Ltd | Professional & scientific | 2012 |
| Black Diamond Cars & Wraps Limited | Manufacturing | 2018 |
| Black Pepper Studio Ltd | Information & communication | 2022 |
| Black Swan Enterprises Limited | Wholesale & retail | 2006 |
| Blackcatpc Limited | Wholesale & retail | 2023 |
| Blackman Builders Limited | Construction | 2015 |
| Blacks Diamond Limited | Other services | 2025 |
| Blade Construction (Southern) Ltd | Construction | 2018 |
| Blamire Investments Ltd | Real estate | 2021 |
| Blankpage Advisory Limited | Professional & scientific | 2023 |
| Bleach Holdings Limited | Real estate | 2015 |
| Blendworth Autocare Ltd | Wholesale & retail | 2011 |
| Blendworth Consultants Ltd | Professional & scientific | 2015 |
| Blendworth Group Ltd | Administrative & support | 2023 |
| Blendworth Internet Cars Ltd | Wholesale & retail | 2019 |
| Blendworth Tree Care Ltd | Administrative & support | 2023 |
| Blendworth Vehicle Repairs Limited | Wholesale & retail | 2003 |
| Blessings Always Guruji Limited | Manufacturing | 2025 |
| Blinding Talent Ltd | Administrative & support | 2021 |
| Bliss Beauty Care Limited | Other services | 2016 |
| Blissful Abodes Ltd | Real estate | 2023 |
| Blockmill Limited | Information & communication | 2022 |
| Blomsy Ltd | Information & communication | 2026 |
| Bloq. Creative Studio Ltd | Professional & scientific | 2022 |
| Blos-Comms Ltd. | Information & communication | 2013 |
| BLP Equestrian Ltd | Agriculture & fishing | 2025 |
| Blue 7 Consultancy Ltd | Professional & scientific | 2019 |
| Blue CAP Enterprises Ltd | Real estate | 2023 |
| Blue Circle Construction & Development Limited | Construction | 2022 |
| Blue Daisy Flat Management Limited | Households | 1990 |
| Blue Dog Technical Services Limited | Information & communication | 2017 |
| Blue Dragon Cards Ltd | Wholesale & retail | 2025 |
| Blue Hexagon Group Limited | Manufacturing | 2024 |
| Blue Jade Solutions Limited | Real estate | 2012 |
| Blue Lens Films Limited | Information & communication | 2015 |
| Blue Mouse Property Limited | Real estate | 2016 |
| Blue Ribbon Socials Limited | Professional & scientific | 2025 |
| Blue Sky (Hampshire) Limited | Construction | 2026 |
| Blue Titan Capital Limited | Administrative & support | 2019 |
| Blue Water Service Ltd | Administrative & support | 2011 |
| Blue Waves Travelling Ltd | Transport & logistics | 2025 |
| Blueberry Communications Ltd | Professional & scientific | 2008 |
| Blueberry Juice Ltd | Arts & recreation | 2014 |
| Blueberryskye Ltd | Wholesale & retail | 2025 |
| Bluechery Limited | Wholesale & retail | 2025 |
| Bluedog Finance Limited | Other services | 2022 |
| Bluegrain Studio Ltd | Information & communication | 2023 |
| Bluemotion Estates Limited | Wholesale & retail | 2010 |
| Bluepark Estates Limited | Real estate | 2002 |
| Bluestone Inspections Ltd | Construction | 2026 |
| Blurred Media TV Limited | Information & communication | 2017 |
| Blutek Limited | Information & communication | 2024 |
| Blvd Properties Limited | Real estate | 2024 |
| Blyth Industries Ltd | Professional & scientific | 2023 |
| BMD Southern Ltd | Manufacturing | 2018 |
| BOB Buddy Ltd | Professional & scientific | 2025 |
| BOB Ware Property Services Ltd | Construction | 2015 |
| Boba Harmony Limited | Hospitality | 2024 |
| Bobo&Bess Limited | Real estate | 2024 |
| Boda Homes Ltd | Construction | 2018 |
| Bodai-Global Limited | Manufacturing | 2015 |
| Body Planners Limited | Wholesale & retail | 2020 |
| Bodyfit Chiropractic Clinic Limited | Health & social care | 2020 |
| Bofo Limited | Information & communication | 2018 |