| Bagpress Limited | Manufacturing | 2002 |
| Baker Jackson Solutions Limited | Manufacturing | 2010 |
| Balauta Ltd | Wholesale & retail | 2015 |
| Baltic Cleaning Services Limited | Administrative & support | 2025 |
| Bamf Rigging Ltd | Construction | 2023 |
| Barber 27 Ltd | Other services | 2024 |
| Barker & Barnet Dog Grooming Ltd | Other services | 2024 |
| Barnard Roofing Ltd | Construction | 2009 |
| Baron Holdco Limited | Financial services | 2020 |
| Baron Safety Developments Limited | Real estate | 1979 |
| Baron Safety Limited | Financial services | 2020 |
| Barry Millers Limited | Other services | 2013 |
| Bars Contracting Limited | Professional & scientific | 2026 |
| Barwell & Jones Limited | Wholesale & retail | 2008 |
| Barwick House Management Company Rushden Ltd | Households | 2019 |
| Baskerville Drummond Consulting Ltd | Information & communication | 2011 |
| Baskerville Drummond LLP | | 2021 |
| BC Events Ltd | Administrative & support | 2025 |
| Beacon Music Education Ltd | Education | 2022 |
| Bear Electrical Contract Solutions Limited | Construction | 2016 |
| Bear Industries Ltd | Wholesale & retail | 2018 |
| Bear Roller Ltd | Real estate | 2024 |
| Bearfoot Property Limited | Real estate | 2018 |
| Bedford Theatre Trust Limited | Arts & recreation | 1974 |
| BEE Cool ACS Ltd | Wholesale & retail | 2020 |
| BEE Right First Time Limited | Professional & scientific | 2023 |
| Beer N' Cheer Limited | Hospitality | 2022 |
| Beljix Ltd | Wholesale & retail | 2014 |
| Belloh's Electrical Services Limited | Construction | 2023 |
| BEN Barber Media Ltd | Information & communication | 2023 |
| Berkshire Distillery Limited | Hospitality | 2019 |
| Berkshire GIN Limited | Wholesale & retail | 2020 |
| Berties of Higham Ltd | Wholesale & retail | 2023 |
| Best Contract Flooring Limited | Construction | 2022 |
| Best Kebab Rushden Ltd | Hospitality | 2022 |
| Best Seller Furniture Ltd | Wholesale & retail | 2025 |
| Bestontrend Limited | Wholesale & retail | 2020 |
| Beyond Bricks Services Ltd | Real estate | 2024 |
| BF Plastering Ltd | Construction | 2024 |
| Bhavini Limited | Real estate | 2023 |
| Bhavna Beauty Ltd | Other services | 2024 |
| BHO Betterhomeoutlook Ltd | Construction | 2020 |
| Bhumika Ltd | Wholesale & retail | 2018 |
| Big Red Roofing Ltd | Construction | 2026 |
| Binary Motors Ltd | Wholesale & retail | 2020 |
| Bishop Legal Services Ltd | Professional & scientific | 2017 |
| Bitan Cleaning Services Ltd | Administrative & support | 2025 |
| Biye Editorial Ltd | Professional & scientific | 2023 |
| BKS Partners Ltd | Professional & scientific | 2025 |
| Black Horse Solutions Ltd | Real estate | 2025 |
| Black Orchid Health Care Ltd | Health & social care | 2026 |
| Blayney Overstone Ltd | Real estate | 2024 |
| Blayney Partnership Limited | Administrative & support | 2005 |
| Blayney Sywell Limited | Administrative & support | 2020 |
| BLC Services Ltd | Transport & logistics | 2023 |
| BLF Developments Ltd | Construction | 2025 |
| Blillov Ltd | Wholesale & retail | 2023 |
| Blue Corner Cafe Ltd | Hospitality | 2024 |
| Blue Gringo Ltd | Transport & logistics | 2025 |
| Blue Orchid Management Ltd | Professional & scientific | 2022 |
| Blue Sparkle Investments Ltd | Financial services | 2024 |
| BMB Grocery Limited | Wholesale & retail | 2017 |
| Boardman Sport and Injury Therapy Limited | Health & social care | 2019 |
| BOB Electrical Ltd | Construction | 2022 |
| BOB Wilson 2000 Limited | Arts & recreation | 2000 |
| Bohemia House UK Ltd | Manufacturing | 1999 |
| Bondsbrook Limited | Wholesale & retail | 2005 |
| Boom Machinery Inspections Limited | Manufacturing | 2018 |
| Bordeaux and Beyond Ltd | Wholesale & retail | 2007 |
| Boujee Barkers Ltd | Agriculture & fishing | 2026 |
| Bound and Bounce Home Improvements Ltd | Construction | 2017 |
| Bound and Bounce Resin Surfaces Ltd | Construction | 2019 |
| Boundary Index Limited | Information & communication | 2025 |
| BOY Limited | Wholesale & retail | 2004 |
| BP Creative Developments Ltd | Other services | 2021 |
| Brad Dell Electrical Services Limited | Construction | 2023 |
| Breecare Limited | Health & social care | 2023 |
| Brett Gavin Limited | Administrative & support | 2013 |
| Brett Jarvis Plastering Ltd | Construction | 2024 |
| Brewmaster's House Limited | Manufacturing | 2018 |
| Brightflames Heating and Plumbing Limited | Administrative & support | 2023 |
| Bring 2GETHER CIC | Other services | 2024 |
| Brisas Properties Ltd | Real estate | 2017 |
| Brit Building Ltd | Construction | 2026 |
| Britannia Management Solutions Ltd | Professional & scientific | 2025 |
| Brookfield Dental Practice Limited | Health & social care | 2022 |
| Brooks Event Services Ltd | Construction | 2020 |
| Brown & Dodge Homes Ltd | Real estate | 2023 |
| Bruce Mphepo Impact Coaching and Consulting Ltd | Education | 2024 |
| Bryntech Limited | Manufacturing | 2008 |
| BSM Technics Limited | Professional & scientific | 2013 |
| BTI Bakes Ltd | Manufacturing | 2026 |
| BTP Healthcare Ltd | Health & social care | 2022 |
| BTS Accountancy Services Ltd | Professional & scientific | 2015 |
| Bubblefresh Limited | Wholesale & retail | 2020 |
| Bubuioc Ltd | Transport & logistics | 2023 |
| Budget Express Courier Ltd | Transport & logistics | 2018 |
| Build IT UP With US Limited | Wholesale & retail | 2023 |
| Building and Construction Recruitment Limited | Administrative & support | 2021 |
| Buildnostics Limited | Information & communication | 2024 |