| Bailey's Electrical Company Ltd | Construction | 2020 |
| Bains & Sons Investments Limited | Real estate | 2017 |
| Baleview Limited | Hospitality | 2004 |
| Balfour Court (Harpenden) Management Company Limited | Households | 1988 |
| Bamville Developments Limited | Construction | 1983 |
| Bamville Investments Limited | Real estate | 2018 |
| Bandos Solutions Limited | Professional & scientific | 2010 |
| Bangkok Lounge Herts Ltd | Hospitality | 2019 |
| Bar Codes for Business Limited | Information & communication | 1992 |
| Bare Knuckle Effects Limited | Information & communication | 2017 |
| Barlings Consultancy Limited | Hospitality | 2009 |
| Barmouth Ltd | Real estate | 2015 |
| Barojac Flat Management Company Limited | Households | 1978 |
| Barra Properties Limited | Real estate | 2016 |
| Bartholomew Nicholas Limited | Real estate | 2020 |
| Barton Blakeley Technologies Limited | Manufacturing | 2016 |
| Barton PS Limited | Real estate | 2018 |
| Baskcreative Ltd | Information & communication | 2021 |
| Batford Day Care Limited | Education | 2004 |
| Batleym Ltd | Construction | 2025 |
| Batman Business Consultancy Ltd | Professional & scientific | 2025 |
| Battell Construction Ltd | Construction | 2025 |
| Batterbury & Sons Limited | Real estate | 2019 |
| Bayford Analysts Ltd | Professional & scientific | 2010 |
| Bayford Court Ltd | Real estate | 2012 |
| Bayfront Developments Limited | Construction | 2026 |
| BB NO 3 Ltd | Administrative & support | 2022 |
| BCL Interiors Limited | Professional & scientific | 2024 |
| BD Health Solutions Ltd | Wholesale & retail | 2021 |
| Bduk Trading Ltd | Wholesale & retail | 2020 |
| BE Still Limited | Health & social care | 2015 |
| BEA Consultancy Services Ltd | Information & communication | 1998 |
| Beach Electrical Ltd | Construction | 2019 |
| Beacon Wills and Probate Ltd | Professional & scientific | 2013 |
| Bear and Rock Ltd | Professional & scientific | 2019 |
| Beaton Business Consultants Ltd | Professional & scientific | 2012 |
| Beaudevon Limited | Other services | 2020 |
| Beausang Investments Limited | Real estate | 2010 |
| Beauty&Vitality Limited | Wholesale & retail | 2018 |
| Bedford Land Ltd | Other services | 2015 |
| Bedfordshire Air Conditioning Limited | Energy | 2019 |
| Beech Ridge Management Company Limited | Households | 1994 |
| Beehive PUB Co Limited | Hospitality | 2007 |
| Beesonend Consulting Limited | Professional & scientific | 2020 |
| Begin Management Limited | Professional & scientific | 2010 |
| Beitaiyang Ltd | Information & communication | 2016 |
| Belgrave House Management Company (Ilkley) Limited | Hospitality | 1987 |
| Belitha Limited | Wholesale & retail | 2009 |
| Bell Classics Limited | Manufacturing | 2019 |
| Belle Aesthetics Hertfordshire Limited | Health & social care | 2024 |
| Bellspire Ltd | Professional & scientific | 2017 |
| Bemyguest Entertainment Ltd | Administrative & support | 2025 |
| Bemyguest Group UK Ltd | Administrative & support | 2024 |
| BEN Humphry Ltd | Professional & scientific | 2020 |
| BEN Strowman Design Ltd | Professional & scientific | 2026 |
| Benchley Hill Developments Ltd | Real estate | 2023 |
| Benkoconsultancy Ltd | Professional & scientific | 2023 |
| Bennets Lodge Management Company Limited | Administrative & support | 2012 |
| Benroc Investments Limited | Real estate | 2016 |
| Bento-Zo Ltd | Hospitality | 2023 |
| Berkeley Dylan Capital Ltd | Real estate | 2026 |
| Bermingham Consulting Limited | Professional & scientific | 2004 |
| Berthold Technologies (UK) Limited | Manufacturing | 2001 |
| Bertini Research Limited | Professional & scientific | 2006 |
| Bespoke Curtains Shutters & Blinds Limited | Manufacturing | 2021 |
| Bespoke Funding Program Ltd | Information & communication | 2022 |
| Bespoke Luxury Gifts Ltd | Manufacturing | 2025 |
| Bespoke Nutritional Therapy Ltd | Extraterritorial | 2017 |
| Best Child Friendly Holidays Ltd | Information & communication | 2023 |
| Best Foods Limited | Wholesale & retail | 2002 |
| Best Start Education Ltd | Education | 2014 |
| Bestwell Consulting Ltd | Information & communication | 2012 |
| Betavue Limited | Information & communication | 2009 |
| Bethrob Ltd | Professional & scientific | 2010 |
| Better Communication CIC | Health & social care | 2011 |
| Beyond the Door Holdings Limited | Information & communication | 2023 |
| BFW of Luton Limited | Wholesale & retail | 2000 |
| BGS Events Ltd | Administrative & support | 2021 |
| Bh&M 2025 Limited | Professional & scientific | 2025 |
| Bhangal Change Management Ltd | Information & communication | 2018 |
| Bhatia Overseas Limited | Wholesale & retail | 2014 |
| Big Cairn Cottages Ltd | Real estate | 2021 |
| BIGDATA4ANALYTICS Ltd | Professional & scientific | 2014 |
| Bihalt Ltd | Information & communication | 2018 |
| Birch Property Consulting Limited | Professional & scientific | 2012 |
| Bishopsgate Transformation Ltd | Information & communication | 2026 |
| Bitrock Consulting Limited | Information & communication | 2014 |
| Bizai Limited | Information & communication | 2019 |
| BJC Energy Services Ltd | Construction | 2026 |
| Blackhorse Lane (Redbourn) Management Company Limited | Households | 2026 |
| Blackstone Property Partners Limited | Real estate | 2026 |
| Blanco Properties Limited | Real estate | 2023 |
| Blandings Consultants Limited | Professional & scientific | 2025 |
| BLD Bigbury Ltd | Hospitality | 2024 |
| BLD Holdings Limited | Real estate | 2019 |
| Bliss Partners Limited | Administrative & support | 2020 |
| Blizzard Voice & Data Ltd | Information & communication | 2010 |
| Blossom Street Aesthetics Ltd | Other services | 2023 |
| Blue Bear Security Limited | Administrative & support | 2020 |
| Blue Building & Maintenance Limited | Construction | 2009 |