| Biriyani House Takeaway Limited | Hospitality | 2025 |
| Bishopsgate Corporate Finance Limited | Financial services | 1977 |
| Bishopsgate Holdings Limited | Financial services | 2024 |
| BK Design Projects Limited | Professional & scientific | 2011 |
| Black Bull Development Company Ltd | Construction | 2024 |
| Black Fort Consultants Limited | Professional & scientific | 2006 |
| Black Type Investments Limited | Real estate | 2008 |
| Blackfriars Associates Ltd | Professional & scientific | 2019 |
| Blackstones Sports & Social Club Limited | Hospitality | 2003 |
| Bland's (Rutland) Ltd | Transport & logistics | 2003 |
| Blhc Ltd | Financial services | 2022 |
| Bliumin Development Ltd | Real estate | 2025 |
| BLL Investments Limited | Professional & scientific | 2010 |
| BLO Hair Studio Ltd | Other services | 2020 |
| Blocksteed Limited | Information & communication | 2020 |
| BLS Trading Ltd | Administrative & support | 2016 |
| Blue H Ltd | Professional & scientific | 2014 |
| Blue Jobs Ltd | Construction | 2024 |
| Blue Line Design Limited | Information & communication | 2006 |
| Blue Rush Marketing Ltd | Professional & scientific | 2025 |
| Blue Sky Equity Trading LLP | | 2015 |
| Bluebell Corner Ltd | Real estate | 2008 |
| Bluepebble Asset Management Limited | Financial services | 2017 |
| Bluesolutions UK Limited | Professional & scientific | 2008 |
| Blythe Advisory Limited | Professional & scientific | 2026 |
| Bmsg Wealth Management Limited | Professional & scientific | 2020 |
| BN2 Ltd | Real estate | 2024 |
| BNG Navigation Limited | Professional & scientific | 2017 |
| Bodhitree Ltd | Information & communication | 2012 |
| Body & Bike Ltd | Manufacturing | 2021 |
| Body Matters (Stamford) Limited | Other services | 2009 |
| Bolin Webb Ltd | Manufacturing | 2009 |
| Bone of Contention Ltd | Professional & scientific | 2021 |
| Bonneyhall Limited | Real estate | 1994 |
| Borderville Management Limited | Extraterritorial | 2013 |
| Bornglobe Systems Limited | Households | 1988 |
| Boss Asset Finance Ltd | Financial services | 2018 |
| Boss Bird Ltd | Wholesale & retail | 2019 |
| Boswell Property Company Limited | Real estate | 1984 |
| Bounce Supplements Ltd | Health & social care | 2025 |
| Bourne Motor Company Ltd | Wholesale & retail | 2006 |
| Bowman Engineering Limited | Manufacturing | 2006 |
| Bpgc Limited | Arts & recreation | 2019 |
| Braceborough Hall Care Home Ltd | Health & social care | 2025 |
| Braceborough Homes Ltd | Real estate | 2025 |
| Braceborough Limited | Health & social care | 2010 |
| BRC Telecoms Ltd | Information & communication | 2024 |
| Bredcroft Limited | Extraterritorial | 2015 |
| Bretton Green Limited | Manufacturing | 2013 |
| Bridgewell Housing Solutions Ltd | Real estate | 2025 |
| Brighter Mortgage Solutions Group Ltd | Financial services | 2018 |
| Brilliant Business Solutions Ltd | Administrative & support | 2012 |
| Britannia Mills Development Company Limited | Construction | 2021 |
| Broad Star Management Company Limited | Households | 2012 |
| Bronze Holdings Limited | Financial services | 2017 |
| Brownlow Terrace Management Company Limited | Households | 2021 |
| Bryman Homes Limited | Real estate | 2017 |
| BTM Agrim, Inc. | | 2007 |
| Bull & Cope Ltd | Construction | 2022 |
| BUNKER48 Limited | Information & communication | 2010 |
| Burghley & Co Eyewear Ltd | Wholesale & retail | 2025 |
| Burghley Barns Limited | Construction | 2013 |
| Burghley Borderville Farm Limited | Real estate | 2020 |
| Burghley Cars Ltd | Wholesale & retail | 2014 |
| Burghley Developments Limited | Construction | 2025 |
| Burghley Electrical Contractors Ltd | Construction | 2026 |
| Burghley Enterprises Limited | Wholesale & retail | 1989 |
| Burghley Estate Farms Limited | Real estate | 1982 |
| Burghley Horse Trials Limited | Arts & recreation | 2009 |
| Burghley House Preservation Trust Limited | Real estate | 1969 |
| Burghley Land Limited | Construction | 2013 |
| Burghley Stamford North Limited | Real estate | 2020 |
| Burkhill Independent Services Ltd | Transport & logistics | 2012 |
| Burmas 19 Limited | Financial services | 2019 |
| Burrough Court Conferences Limited | Real estate | 2017 |
| Burwell Group Limited | Health & social care | 2026 |
| Business EQ Ltd | Professional & scientific | 2011 |
| Buswell Shooter Tagg Limited | Professional & scientific | 2025 |
| Buyam Limited | Wholesale & retail | 2024 |
| BY the Glovers Ltd | Real estate | 2025 |
| Byoode.Studio Ltd | Extraterritorial | 2024 |
| C & D Group Holdings (UK) Limited | Financial services | 2017 |
| C & D Group Holdings Limited | Financial services | 2012 |
| C.J. Carpets + Lighting Ltd | Wholesale & retail | 2013 |
| C.S.Fenn and Sons (Ryhall) Limited | Construction | 1958 |
| C.S.Harris Engineering & Surveying Ltd | Construction | 2021 |
| C2G Consulting Limited | Professional & scientific | 2014 |
| C2S Group Ltd | Hospitality | 2015 |
| C5 Business Consulting Limited | Professional & scientific | 2023 |
| CAD Engineering Services Limited | Information & communication | 2015 |
| Caddy Comps Ltd | Wholesale & retail | 2021 |
| Caddy Customs Ltd | Professional & scientific | 2015 |
| Cadman Homes Limited | Construction | 1969 |
| Cadman(Developments)Limited | Construction | 1961 |
| Cady Flooring Ltd | Construction | 2024 |
| Cafe AU Chocolat Ltd | Wholesale & retail | 2014 |
| CAG Enterprises (Stamford) Limited | Construction | 2012 |
| Cakesco Ltd | Manufacturing | 2022 |
| Callow Hall Limited | Hospitality | 2016 |
| Cambria Geological Services Ltd | Professional & scientific | 2021 |