| 03606747 Limited | Wholesale & retail | 1998 |
| 05247773 Limited | Extraterritorial | 2004 |
| 06 Studio Ltd | Information & communication | 2024 |
| 1 & 3 Kenton Gardens Freehold Ltd | Households | 2007 |
| 1 Blenheim Road (Barnet) Management Co. Limited | Households | 2003 |
| 10 Goulton Road Limited | Real estate | 2008 |
| 10275364 Ltd | Health & social care | 2016 |
| 15 College Road Management Company Limited | Real estate | 2007 |
| 18 and 20 Chesterfield Road Management Company Limited | Households | 1990 |
| 1ST Class Data and Electrical Services Limited | Construction | 2001 |
| 1ST Reset Limited | Construction | 2004 |
| 2 Blenheim Road Management Company Limited | Households | 2005 |
| 21 Park Avenue South Harpenden Management Limited | Households | 1989 |
| 210 Turners Hill Limited | Extraterritorial | 2002 |
| 21ST Century Web Limited | Information & communication | 1997 |
| 24 Lock & Key Ltd | Other services | 2020 |
| 2PLATES Limited | Real estate | 2022 |
| 3 Points Cafe Ltd | Hospitality | 2018 |
| 32 Creative Limited | Professional & scientific | 2002 |
| 340 Flat Management Limited | Real estate | 2000 |
| 39 ST Lukes Road Management Limited | Households | 2001 |
| 4 and 4A Little Hyde Company Limited | Households | 2004 |
| 41 Park Road Limited | Extraterritorial | 2007 |
| 43 Station Road Limited | Households | 1996 |
| 48 Somerset Road New Barnet Limited | Households | 2005 |
| 49A Park Avenue Limited | Real estate | 2007 |
| 4A Homes Ltd | Real estate | 2021 |
| 4SIGHT Limited | Administrative & support | 2000 |
| 5-7 Cranbrook Drive Limited | Professional & scientific | 2000 |
| 51 High Street Buntingford Management Company Limited | Households | 2006 |
| 51 Pegasus Limited | Construction | 1999 |
| 51-55 Puller Road (Barnet) Limited | Households | 1992 |
| 55 Design Ltd | Arts & recreation | 2004 |
| 7 Mountains Properties Ltd | Real estate | 2020 |
| 75, 77, 79 and 81 the Crescent, Abbots Langley Ltd | Real estate | 1997 |
| 8, 9 & 10 Brook Lane Property Management Limited | Households | 2005 |
| 9 Lives Furniture | Wholesale & retail | 2002 |
| 9-15 Churchfield Path Management Company Limited | Households | 2005 |
| A & B Tyres Limited | Real estate | 1991 |
| A & F Scaffolding Ltd | Construction | 2012 |
| A B W Services Limited | Construction | 2004 |
| A Completely Individual Design Ltd | Information & communication | 2008 |
| A D BLY Construction Limited | Construction | 2003 |
| A Dimond Flooring Limited | Construction | 2007 |
| A J Martel Limited | Wholesale & retail | 2003 |
| A Jaggi Physio Consultancy Ltd | Health & social care | 2012 |
| A O Enterprises Limited | Manufacturing | 2004 |
| A R Batchelor Limited | Construction | 2004 |
| A to B IT Services Limited | Information & communication | 2004 |
| A&K Wilson Picture Framers Ltd | Wholesale & retail | 2002 |
| A&M Installations Ltd | Construction | 2021 |
| A-Top Management Services Limited | Real estate | 1986 |
| A. J. Neumann & Co. Limited | Other services | 1960 |
| A. Maxwell Limited | Health & social care | 2006 |
| A.C.L. Engineering Limited | Wholesale & retail | 1980 |
| A.D.B Cars Repairs Ltd | Wholesale & retail | 2019 |
| A.E.& D.A.Thomson Limited | Real estate | 1954 |
| A.E.Bullock Limited | Construction | 1966 |
| A.G. Evans Ltd. | Other services | 1997 |
| A.G. Hipgrave Limited | Construction | 1979 |
| A.J. Maxwell Limited | Agriculture & fishing | 1948 |
| A.M. Dental Supplies Limited | Other services | 1994 |
| A.M.R. Computer Consultants Limited | Wholesale & retail | 1995 |
| A.P.& a. Limited | Wholesale & retail | 1988 |
| A.R.T.I. Services Limited | Health & social care | 2000 |
| A.T.P.Decorations Limited | Construction | 1964 |
| A1 Euro Limited | Real estate | 1999 |
| Aaron Homes Limited | Construction | 2003 |
| AB Computing Limited | Information & communication | 1995 |
| Abacus (DP) Limited | Professional & scientific | 1976 |
| Abacus 246 Limited | Professional & scientific | 2004 |
| Abacus House Limited | Real estate | 2007 |
| Abbey Car Care Ltd | Administrative & support | 2012 |
| Abbey Properties Limited | Professional & scientific | 1947 |
| Abbington Hotel Limited | Hospitality | 2006 |
| Abbots Langley Flowers Limited | Wholesale & retail | 2002 |
| ABC Docklands Limited | Real estate | 2005 |
| ABD Services (England) Ltd | Manufacturing | 2013 |
| Abeks Konsult Limited | Information & communication | 2010 |
| Abicem.Ltd | Information & communication | 2006 |
| Ablazers Performing Arts Education Limited | Arts & recreation | 2025 |
| Able Accounting Services Limited | Professional & scientific | 1992 |
| About Time Enterprises Limited | Information & communication | 2003 |
| Abridge Court (Waltham Cross) Limited | Professional & scientific | 1989 |
| ABS Chauffeurs Ltd | Other services | 2015 |
| Absolute Internet Consultants Ltd | Information & communication | 1998 |
| Absolute Style Limousines Limited | Transport & logistics | 2001 |
| Abundant Solutions Ltd | Professional & scientific | 2007 |
| AC Pullen Limited | Professional & scientific | 1983 |
| Academy of Computer and Management Science Education Great Britain | Education | 2007 |
| Academy of Executive Coaching Limited | Education | 2002 |
| ACCOUNT2ACCOUNT Limited | Extraterritorial | 2000 |
| Accountancy Plus Plus Limited | Professional & scientific | 1996 |
| Ace Communications (Ware) Limited | Information & communication | 2002 |
| Acechoice.Com Ltd | Transport & logistics | 2002 |
| Acevale Limited | Other services | 2013 |
| Acidtested Limited | Information & communication | 1999 |
| Acme Business Solutions Limited | Wholesale & retail | 2001 |
| ACN Plumbing Heating and GAS Ltd | Construction | 2024 |
| Acorn Life Coaching & Hypnotherapy Ltd | Health & social care | 2024 |