| & Smith Limited | Arts & recreation | 2008 |
| 1 Cross Hill Management Company Limited | Households | 1997 |
| 128 Whitchurch Lane (Edgware) Limited | Households | 2019 |
| 1404 Digital Theraputics Limited | Information & communication | 2023 |
| 164 ST Albans Road (Freehold) Limited | Real estate | 2024 |
| 17046962 Limited | Information & communication | 2026 |
| 17048754 Ltd | Information & communication | 2026 |
| 17048758 Ltd | Information & communication | 2026 |
| 17048783 Ltd | Information & communication | 2026 |
| 1980 Holdings Limited | Financial services | 2026 |
| 22 Ashburton Road Southsea (Management) Limited | Real estate | 2000 |
| 26 Abbey Road Limited | Households | 1997 |
| 27 BSW Limited | Real estate | 2016 |
| 27 ST Johns Road Watford Limited | Real estate | 2006 |
| 28 Christchurch Avenue Freehold Ltd | Real estate | 2011 |
| 28 Clarendon Road Limited | Real estate | 2025 |
| 2MK Properties Limited | Real estate | 2022 |
| 2VH Hospitality Limited | Wholesale & retail | 2024 |
| 3-FOURTEEN Design Limited | Professional & scientific | 2024 |
| 316MC Limited | Arts & recreation | 2017 |
| 6MED Ltd | Education | 2013 |
| 888 Estimating Services Ltd | Construction | 2019 |
| 9 Watford Road Property Management Company Limited | Households | 2015 |
| 92 Ltd | Real estate | 2019 |
| A J Bridgeman Ltd | Water & waste | 2024 |
| A Slice of Cake Ltd | Manufacturing | 2010 |
| A&A Realty Limited | Real estate | 2015 |
| A.C.O Heating and Plumbing Limited | Construction | 2016 |
| A2B Performance Ltd | Wholesale & retail | 2011 |
| Abacus 2 Limited | Professional & scientific | 2013 |
| Abacus Credit Insurance Brokers Ltd | Financial services | 2019 |
| Abacus Developments Limited | Construction | 1972 |
| Abacus Projects Limited | Construction | 1979 |
| Abacus Transport Limited | Transport & logistics | 1994 |
| Abbey Consultants (Southern) Limited | Professional & scientific | 2004 |
| Abbey Study Group Ltd | Real estate | 2009 |
| Abbots Langley Association Limited | Other services | 2026 |
| Abiciu Ltd | Real estate | 2024 |
| Able Data Holdings Limited | Information & communication | 2008 |
| Able Data Installations Limited | Construction | 1991 |
| About Grace PR Ltd | Professional & scientific | 2020 |
| Absolute Publishing Limited | Extraterritorial | 2014 |
| Abstract Construction Limited | Construction | 2008 |
| Abujafar Ltd | Arts & recreation | 2013 |
| Ace Teleprompt & Production Ltd | Information & communication | 2025 |
| Aced Technologies Limited | Wholesale & retail | 2026 |
| Active Management Centre Ltd | Financial services | 2026 |
| Adamant Limited | Administrative & support | 2021 |
| ADI Stag Ltd | Construction | 2026 |
| ADL Ventures Limited | Construction | 1994 |
| Adtentus Limited | Professional & scientific | 2007 |
| Advance Trade Solutions Limited | Professional & scientific | 2012 |
| Adventure Integrated Services Ltd | Information & communication | 2025 |
| Aether Consulting Limited | Professional & scientific | 2020 |
| Afittermedg Ltd | Other services | 2018 |
| Afterburner Genesis Ltd | Information & communication | 2025 |
| Afterburner Stardust Ltd | Information & communication | 2025 |
| Agarsen Capital Limited | Financial services | 2024 |
| Agarsen Properties Limited | Real estate | 2021 |
| AGJ Capital Limited | Professional & scientific | 2025 |
| Agsm Maintenance Holdings Limited | Financial services | 2025 |
| Agsm Maintenance Limited | Construction | 2014 |
| AHK Management Limited | Professional & scientific | 2013 |
| Aila Recruitment Ltd | Administrative & support | 2020 |
| Air 3 Limited | Construction | 2001 |
| Aircrafft Designs Limited | Arts & recreation | 2018 |
| Airtraxuk Ltd | Wholesale & retail | 2025 |
| AJB Accounting Limited | Professional & scientific | 2024 |
| AJB Cyber Advisory Limited | Information & communication | 2025 |
| AJB Group (Oxfordshire) Ltd | Administrative & support | 2017 |
| Ajma Products Limited | Wholesale & retail | 2020 |
| AJW Commercial Ltd | Professional & scientific | 2019 |
| AL Falah Barakah Property Group Ltd | Construction | 2026 |
| Alex Minors Limited | Arts & recreation | 2006 |
| Alfa Cabling Limited | Other services | 2013 |
| Alicap Investments Ltd | Real estate | 2020 |
| Alicap Solutions Ltd | Real estate | 2004 |
| Alignment Construction Ltd | Construction | 2026 |
| Alignment Properties Limited | Construction | 2016 |
| ALL Aboard Kids Club Limited | Health & social care | 2019 |
| ALL Weather Roofing (Herts) Limited | Construction | 2007 |
| Alliance of Independent Promoters (UK) CIC | Other services | 2023 |
| Allsorted Ltd | Wholesale & retail | 2010 |
| Almax Facilities Management Ltd | Professional & scientific | 2026 |
| Almax Property Limited | Other services | 2026 |
| Almay Scenic Limited | Arts & recreation | 2023 |
| Alpiana Stone Ltd | Construction | 2011 |
| Altahullion Energy Limited | Energy | 2023 |
| Altus Engineering Consultants Ltd | Professional & scientific | 2025 |
| Aludra Bess Ltd | Professional & scientific | 2020 |
| Amavo Creations Ltd | Information & communication | 2025 |
| AMC Construction Solutions Ltd | Construction | 2019 |
| Amplify Creators Limited | Professional & scientific | 2021 |
| AMR Sealants Ltd | Construction | 2022 |
| AN Evening With Limited | Arts & recreation | 2025 |
| Anchor Sound and Security Ltd | Administrative & support | 2017 |
| Andy White Creative Ltd | Arts & recreation | 2014 |
| Angharad Rees Limited | Manufacturing | 2002 |
| Annibells Ltd | Wholesale & retail | 2024 |
| Antonio Russo Art Company Limited | Administrative & support | 2014 |