| Basicdrive Limited | Information & communication | 1989 |
| Basildon After School Club Ltd | Education | 2019 |
| Basildon Autos Ltd | Wholesale & retail | 2025 |
| Basilico Italian Ltd | Hospitality | 2019 |
| Basit Financial Services Limited | Financial services | 2022 |
| BASIV07 Ltd | Hospitality | 2024 |
| Basraouilabs Ltd | Information & communication | 2025 |
| Bassett News Limited | Wholesale & retail | 2014 |
| Bastal Recruits Ltd | Wholesale & retail | 2021 |
| Bastian Transport Services Ltd | Transport & logistics | 2017 |
| Bastianfra Limited | Agriculture & fishing | 2023 |
| Bastion Property Development Ltd | Construction | 2012 |
| BAT System Services Ltd | Wholesale & retail | 2019 |
| Batch Roofing Specialist Ltd | Construction | 2024 |
| Batchelor Travel Ltd | Administrative & support | 2025 |
| Bateman Brothers (1953) Limited | Wholesale & retail | 1953 |
| Bateman Opticians Ltd | Health & social care | 2013 |
| Bater Law Ltd | Professional & scientific | 2017 |
| Bates Fulfilment Ltd | Transport & logistics | 2020 |
| Bath Best Food Ltd | Hospitality | 2020 |
| Bath Deli Ltd | Hospitality | 2020 |
| Bath Honey Boys Limited | Manufacturing | 2025 |
| Bath Road OFF Licence & Grocery Ltd | Wholesale & retail | 2022 |
| Bathe Ltd | Construction | 2020 |
| Bathinda Mart Ltd | Wholesale & retail | 2025 |
| Bathrooms and Kitchens by NJM & Sons Ltd | Construction | 2024 |
| Batisia Limited | Information & communication | 2026 |
| Batist Alliance PC | | 2018 |
| Baton Court Cardiff Ltd | Real estate | 2024 |
| Batonnagewines Ltd | Wholesale & retail | 2018 |
| Batra Medical Ltd | Health & social care | 2014 |
| Battenbo Engineering Services and Technology Ltd | Professional & scientific | 2020 |
| Battencorp Ltd | Professional & scientific | 2020 |
| Battersea Studios Ltd | Other services | 2024 |
| Battle Motoring Ltd | Wholesale & retail | 2019 |
| Battlepoint Ltd | Arts & recreation | 2019 |
| BAU Solutions Limited | Administrative & support | 2005 |
| BAU UK Ltd | Construction | 2020 |
| Bau-Management & Baustoff-Grosshandel Ltd | Construction | 2019 |
| Baudin Ltd | Wholesale & retail | 2018 |
| Bauer International Ltd | Extraterritorial | 2018 |
| Bauhinia Manor Limited | Extraterritorial | 2021 |
| Baumanagement International Ltd. | Administrative & support | 2019 |
| Baume Shop Ltd | Wholesale & retail | 2024 |
| Baustein IT Solutions Ltd | Wholesale & retail | 2025 |
| Bawales Holding Ltd | Information & communication | 2022 |
| Bawnboy Ltd | Manufacturing | 2020 |
| Bawso Ltd | Hospitality | 1996 |
| Bawso Training and Interpreting Services Limited | Information & communication | 2008 |
| Baxville Limited | Wholesale & retail | 2014 |
| Bay & Beyond Escapes Ltd | Real estate | 2025 |
| Bay Car Transport Ltd | Transport & logistics | 2025 |
| Bay City Living Limited | Real estate | 2010 |
| Bay Comm Limited | Construction | 2021 |
| Bay Contractors Ltd | Construction | 2021 |
| Bay Holdings Limited | Professional & scientific | 1988 |
| Bay House Dental Practice Limited | Health & social care | 2010 |
| Bay Marine Insurance Consultants Limited | Financial services | 2003 |
| Bay Productions Limited | Other services | 2011 |
| Bay Provisions Limited | Wholesale & retail | 2014 |
| Bay Residential Investments Ltd | Real estate | 2015 |
| Bay Store 1 Ltd | Wholesale & retail | 2026 |
| Bay Traders Limited | Hospitality | 2017 |
| Bay Trading Group Ltd | Wholesale & retail | 2018 |
| Bay Vehicles Limited | Wholesale & retail | 2008 |
| Bay View (Penarth) Management Company Ltd | Households | 2025 |
| Bay View Hideaways Ltd | Real estate | 2025 |
| Baya Digital Solutions Ltd | Wholesale & retail | 2021 |
| Bayan Academy CIC | Education | 2022 |
| Bayan Auto Ltd | Wholesale & retail | 2026 |
| Bayati Rail Services Limited | Administrative & support | 2024 |
| Baybark Enterprises Ltd | Other services | 2026 |
| Baybench Limited | Hospitality | 2016 |
| Baybrook Limited | Real estate | 1999 |
| Baycross Limited | Real estate | 2019 |
| Baydata Ltd | Professional & scientific | 2025 |
| Baydragon Limited | Professional & scientific | 2005 |
| Bayfield Bespoke Services Limited | Construction | 2017 |
| Bayit Zahav Ltd | Other services | 2016 |
| Bayleaf (Wales) Limited | Hospitality | 2012 |
| Bayleaf Cuisine Limited | Hospitality | 2016 |
| Bayleigh Limited | Health & social care | 2023 |
| Bayliss Property Group Ltd | Real estate | 2019 |
| Bayliss, Thomas & Co. Limited | Manufacturing | 2020 |
| Bayonne Media Consultancy Ltd | Professional & scientific | 2025 |
| Bayprod Holdings Limited | Financial services | 2013 |
| Bayred Ltd | Wholesale & retail | 2026 |
| Bays Sports Ltd | Manufacturing | 2021 |
| Bayscape Holdings Limited | Construction | 2010 |
| Bayscape Living (Nyon) Limited | Real estate | 2025 |
| Bayscape Residential (Number 3) Limited | Real estate | 2020 |
| Bayscape Residential Ltd | Real estate | 2019 |
| Bayser Ltd | Wholesale & retail | 2025 |
| Bayside (Cardiff) Limited | Real estate | 2018 |
| Bayside Barber Co. Ltd | Other services | 2025 |
| Bayside Engineering Ltd | Manufacturing | 2000 |
| Bayside Enterprises Limited | Administrative & support | 2007 |
| Bayside Productions Ltd | Arts & recreation | 2026 |
| Bayswater Products Ltd | Wholesale & retail | 1994 |
| Baytech Business Solutions PVT Ltd | Financial services | 2025 |