| 4SIGHT Sport Limited | Other services | 2006 |
| 911 Lettings Limited | Administrative & support | 2020 |
| A & N Consultancy Limited | Professional & scientific | 2004 |
| A & R Munson Limited | Health & social care | 2004 |
| A Bell Holdings Limited | Financial services | 2005 |
| A. J Components Ltd | Wholesale & retail | 1999 |
| A. Jones Roofing & Cladding Limited | Construction | 2007 |
| A.S. Agriservices Limited | Hospitality | 2003 |
| A.S.C. Metals Limited | Wholesale & retail | 1979 |
| A43 Developments Limited | Construction | 2003 |
| Aamazing Ltd | Wholesale & retail | 2017 |
| Aaron Tawny Mortgages Limited | Professional & scientific | 2000 |
| Abbeyross Investments Limited | Real estate | 2003 |
| Abbotts Removals Limited | Other services | 2005 |
| Abington Consulting Engineers Limited | Construction | 2007 |
| Abovechance Limited | Households | 1992 |
| Accidental Repair Technicians Limited | Manufacturing | 2002 |
| Ace Mini Skips Limited | Administrative & support | 1985 |
| Achieve Stylish Living Limited | Wholesale & retail | 2002 |
| Acorn Aluminium Limited | Construction | 1992 |
| Acornspire Limited | Extraterritorial | 2005 |
| Acts 9 Developments Ltd | Construction | 2021 |
| Adlogo Limited | Administrative & support | 2002 |
| Advanced System Solutions Ltd | Information & communication | 1998 |
| Affinity Mortgage Solutions Limited | Financial services | 2002 |
| Agape in Action | Health & social care | 1998 |
| Airwair (1994) Limited | Professional & scientific | 1993 |
| Airwair (1996) Limited | Professional & scientific | 1996 |
| Airwair International Limited | Wholesale & retail | 1995 |
| Airwair Limited | Professional & scientific | 1988 |
| Airwair Property Limited | Real estate | 1988 |
| Albany Shed Company Limited | Construction | 1984 |
| ALL OUT Media Limited | Professional & scientific | 2005 |
| Allan Marlow Mortgages Limited | Financial services | 2006 |
| Amakas Limited | Health & social care | 2024 |
| Ambiserve Refrigeration Ltd. | Other services | 2005 |
| Ananstore Limited | Arts & recreation | 2000 |
| Andrew Pullen Limited | Construction | 2002 |
| Andy Durrant Limited | Construction | 2002 |
| Antari Barber Ltd | Other services | 2017 |
| Anthony Brooks Limited | Wholesale & retail | 1997 |
| Apex Business Development Limited | Professional & scientific | 1988 |
| Apex Land Investment Limited | Agriculture & fishing | 2004 |
| Apple Rochester Gears Limited | Extraterritorial | 1984 |
| Arford Enterprises Limited | Administrative & support | 2007 |
| Aril Jewels Ltd | Manufacturing | 2021 |
| ARK Health & Safety Consultants Limited | Professional & scientific | 2006 |
| Armeov Limited | Wholesale & retail | 2026 |
| Arnold Thomson Limited | Professional & scientific | 2007 |
| Ashby Holdings Limited | Financial services | 2019 |
| Ashdon Homes Ltd | Real estate | 2021 |
| Ashworth Building Consultants Limited | Construction | 2005 |
| Astromount Developments Limited | Construction | 1979 |
| Atlantico Computing Ltd | Information & communication | 1998 |
| Automotive Technology (UK) Limited | Manufacturing | 2006 |
| Autoworld Northampton Limited | Wholesale & retail | 1992 |
| B W C (Holdings) Limited | Real estate | 1942 |
| B.A. Components Limited | Manufacturing | 1998 |
| B.W. Systems Limited | Manufacturing | 1998 |
| Bacchus Marsh Limited | Wholesale & retail | 2001 |
| Back of the NET FC Limited | Extraterritorial | 2004 |
| Bajaj Retail Ltd | Wholesale & retail | 2025 |
| Barkers Shoes (Sales) Limited | Manufacturing | 1956 |
| Bartley Industries Limited | Manufacturing | 1964 |
| Barton Plastering Limited | Construction | 2004 |
| Beacon Water Treatments Limited | Manufacturing | 1986 |
| Beauty Hair and Cosmetics (Northampton) Ltd | Wholesale & retail | 2025 |
| Bechel Limited | Professional & scientific | 1999 |
| Becool Radiators Limited | Manufacturing | 1985 |
| Bedford Body Services Limited | Wholesale & retail | 2005 |
| Beeches Nominees Limited | Administrative & support | 1959 |
| Behavioural Referrals Ltd | Professional & scientific | 2002 |
| Belle Casa (Cambridge) Limited | Administrative & support | 2002 |
| Belmont Consulting Limited | Information & communication | 1998 |
| Bentley Property (Northampton) Ltd | Financial services | 2006 |
| Bevingtons Limited | Arts & recreation | 1980 |
| Beyond Newco 123 Limited | Professional & scientific | 2025 |
| BFP Management Company Limited | Professional & scientific | 1997 |
| BGN Live Limited | Professional & scientific | 2016 |
| Biesse Group UK Limited | Manufacturing | 1992 |
| Big Bulk Ltd | Wholesale & retail | 2026 |
| Blakeston Plastering and Rendering Limited | Construction | 2002 |
| Blanmar 1 LLP | | 2008 |
| BLANMAR2 LLP | | 2009 |
| Blenkinsop Leathers Limited | Manufacturing | 1989 |
| Block AID UK (Smith & West) Limited | Public administration | 2005 |
| Blue Sky Photos Limited | Professional & scientific | 2004 |
| Bonfram Limited | Hospitality | 1971 |
| Boston Investco Limited | Financial services | 2025 |
| Bosworth's Nurseries & Garden Centre Limited | Wholesale & retail | 2003 |
| Bosworths Landscaping Ltd | Administrative & support | 2003 |
| BPS Care Homes Limited | Professional & scientific | 2004 |
| Brace Design Limited | Professional & scientific | 2003 |
| Bradshaw Clan Limited | Arts & recreation | 1994 |
| Bravissimo Group Limited | Financial services | 2017 |
| Bravissimo Limited | Wholesale & retail | 1997 |
| Brian Eccles Hearing Centre Limited | Health & social care | 2004 |
| Bridge House Property Management Limited | Households | 2003 |
| Briggs (U.K.) Limited | Manufacturing | 1984 |
| Britannia Fabrications Limited | Wholesale & retail | 1970 |