| Babyloft Ltd | Administrative & support | 2013 |
| Baca Workwear & Safety Ltd | Wholesale & retail | 2009 |
| Baciu Ovidiu-Florin Ltd | Transport & logistics | 2024 |
| Baciu Sell Ltd | Wholesale & retail | 2024 |
| Back 9 Holdings Ltd | Financial services | 2021 |
| Back and Body (Holdings) Limited | Health & social care | 2018 |
| Back and Body Bedford (Great Denham) Limited | Health & social care | 2018 |
| Back and Body Limited | Health & social care | 2015 |
| Back and Body Medical Ltd | Health & social care | 2021 |
| Back and Body Milton Keynes Limited | Health & social care | 2025 |
| Back and Body Towcester Limited | Health & social care | 2024 |
| Back to Earth Creative Ltd | Professional & scientific | 2026 |
| Backbone Wishbone Limited | Professional & scientific | 2016 |
| Backs Enterprises Limited | Professional & scientific | 2018 |
| Backyard Card Ltd | Wholesale & retail | 2023 |
| Backyard Properties Ltd | Real estate | 2021 |
| BAD Butler Ltd | Hospitality | 2020 |
| BAD Dog Barking Limited | Information & communication | 2025 |
| BAD Dog Films Ltd | Arts & recreation | 2004 |
| BAD Wolf (IHS2) Ltd | Information & communication | 2021 |
| Bad-Fox Productions Ltd | Information & communication | 2023 |
| Badby Bluebell Properties Limited | Real estate | 2025 |
| Badco & Co Ltd | Manufacturing | 2022 |
| Badel Services Ltd | Wholesale & retail | 2024 |
| BADER30 UK Ltd | Wholesale & retail | 2024 |
| Badger Sports Limited | Wholesale & retail | 2014 |
| Badjie Limited | Transport & logistics | 2024 |
| Badwell ASH Residents Management Company Limited | Real estate | 2024 |
| BAF Scaffolding Limited | Construction | 2020 |
| BAG Haulage Ltd | Transport & logistics | 2025 |
| BAH Business Ltd | Wholesale & retail | 2023 |
| BAH Pharma Ltd | Wholesale & retail | 2020 |
| Bahez Decor Ltd | Construction | 2025 |
| Bahiti Limited | Administrative & support | 1992 |
| Bailey & Jones Hair Ltd | Other services | 2017 |
| Bailey Motorhome Centre Ltd | Wholesale & retail | 2026 |
| Bailey's & Co. Company Ltd | Other services | 2022 |
| Bailham Psychological Services Limited | Health & social care | 2009 |
| Bainbridge & Co Mortgages Limited | Financial services | 2022 |
| Baines Consulting Ltd | Information & communication | 2022 |
| Bainrock Limited | Professional & scientific | 2021 |
| Bains Private Finance Limited | Financial services | 2025 |
| Baird Oliver Limited | Professional & scientific | 2014 |
| Baird Plant Hire Ltd | Construction | 2026 |
| BAKER-C0LLINS Communications Limited | Professional & scientific | 2018 |
| Bakerlile Limited | Professional & scientific | 2013 |
| Bakers Basco Limited | Manufacturing | 2006 |
| Bakes by Shayma Ltd | Hospitality | 2022 |
| Baki Limited | Other services | 2015 |
| Baklava Ltd | Hospitality | 2019 |
| Balaie Limited | Health & social care | 2021 |
| Balance Body & Mind Limited | Health & social care | 2021 |
| Balanced Body Clinic Northampton Ltd | Health & social care | 2025 |
| Balanced Fayre Limited | Hospitality | 2014 |
| Balbougie Energy Centre II Limited | Energy | 2021 |
| Baldwin Court (Northampton) Management Company Limited | Households | 2017 |
| Balford Limited | Real estate | 2025 |
| Balhoon Limited | Information & communication | 2025 |
| Balkan Breeze Ltd | Hospitality | 2025 |
| Balkan Club Ltd | Hospitality | 2025 |
| Balkan FAM Ltd | Professional & scientific | 2022 |
| Ballard IQ Ltd | Information & communication | 2025 |
| Ballerfantv Limited | Information & communication | 2025 |
| Balloonme Ltd | Wholesale & retail | 2021 |
| Balloons Deluxe Limited | Hospitality | 2025 |
| Bally Brickwork Limited | Construction | 2020 |
| Balm of Gilead Health Care Services Limited | Health & social care | 2016 |
| Balmoral Support Services Ltd | Health & social care | 2023 |
| Balmoral Ltd | Administrative & support | 2015 |
| Balmoral Pharmacy Limited | Wholesale & retail | 2009 |
| Balmoral Place (Northampton) Ltd | Health & social care | 2020 |
| Balmoral Property (Northampton) Ltd | Real estate | 2015 |
| Baloo 24 Ltd | Hospitality | 2024 |
| Baltali Group UK Ltd | Wholesale & retail | 2024 |
| Balti Central Limited | Real estate | 2017 |
| Baltic Court Residents Association Limited | Households | 1987 |
| Baltika Market Ltd | Wholesale & retail | 2021 |
| BAM Land Limited | Extraterritorial | 2014 |
| BAM Paving Limited | Construction | 2015 |
| Bambaloo Limited | Manufacturing | 2025 |
| Bamboo 37 Limited | Hospitality | 2021 |
| BAMBU89 Ltd | Transport & logistics | 2020 |
| Banbury Orthodontics Limited | Health & social care | 2019 |
| Banbury Orthodontics Property Limited | Health & social care | 2024 |
| Banbury Vintage Watch and Jewellery Company Ltd | Wholesale & retail | 2016 |
| Bandcyber Limited | Real estate | 2000 |
| Bandeira Ltd | Information & communication | 2025 |
| Bang on Productions Limited | Information & communication | 2008 |
| Bangladesh Trade Centre Limited | Information & communication | 2010 |
| Bani Accountancy Services Ltd | Professional & scientific | 2017 |
| Banjos Limited | Hospitality | 2000 |
| Banjoure Limited | Information & communication | 2014 |
| Bankfoot Technical and Quality Limited | Professional & scientific | 2018 |
| Bankfoot Training Limited | Professional & scientific | 2022 |
| Banks Farming Limited | Agriculture & fishing | 2016 |
| Banks' Storage Ltd | Real estate | 2020 |
| Bannaventa Ltd | Hospitality | 2020 |
| Bannister Builders Limited | Construction | 2021 |
| Bannister Property Ventures Ltd | Real estate | 2024 |
| Banoful Cafe Sweets and Savouries Ltd | Wholesale & retail | 2023 |