| A-Head 4 Healeys Limited | Wholesale & retail | 2006 |
| A.C. & Co Services Ltd | Transport & logistics | 2019 |
| A.G. Bishop & Sons (Holdings) Limited | Real estate | 1946 |
| A.G. Tiling Ltd | Construction | 2024 |
| A.Horbowski Ltd | Transport & logistics | 2022 |
| A.I.G. Invest Ltd | Construction | 2025 |
| A.S.B. Software Limited | Professional & scientific | 1987 |
| A.S.Pitan Consultants (UK) Limited | Administrative & support | 2019 |
| A.W. Express Ltd. | Transport & logistics | 1998 |
| A.W.Precision Limited | Manufacturing | 1970 |
| A1 Bailiff Services Ltd. | Professional & scientific | 2003 |
| A10 Digital Limited | Professional & scientific | 2024 |
| A1FF UK Ltd | Transport & logistics | 2018 |
| A2B123 Ltd | Transport & logistics | 2026 |
| AA Filling Ltd | Wholesale & retail | 2022 |
| AAA Diamonds Limited | Wholesale & retail | 2017 |
| AAA Valeting Ltd | Administrative & support | 2019 |
| AAB IT Ltd | Information & communication | 2018 |
| AAB Productions Ltd | Transport & logistics | 2020 |
| Aadyaram Ltd | Real estate | 2019 |
| AAI Krupa Limited | Real estate | 2020 |
| AAI Sonal Ltd | Real estate | 2026 |
| Aakp Investment Ltd. | Real estate | 2022 |
| Aanish Property Limited | Real estate | 2025 |
| Aarkiya Group Ltd | Financial services | 2025 |
| Aarkiya PROPERTY1 Ltd | Real estate | 2025 |
| Aaron Martin Fit Ltd | Arts & recreation | 2021 |
| Aaron Martin Golf Ltd | Information & communication | 2024 |
| Aarubi Estate Ltd | Real estate | 2020 |
| Aarubi Finance Ltd | Financial services | 2025 |
| Aarubi Ltd | Wholesale & retail | 2018 |
| Aaryusha Ltd | Professional & scientific | 2024 |
| Aashrit Limited | Professional & scientific | 2019 |
| AB Trans Ltd | Transport & logistics | 2019 |
| Abbey Car Trade Ltd | Wholesale & retail | 2005 |
| Abbey Motor Services Limited | Wholesale & retail | 2023 |
| Abca Solutions Ltd | Administrative & support | 2022 |
| Abc’S Italian Ltd | Hospitality | 2025 |
| Abigail Grace Beauty Training Academy Ltd | Education | 2021 |
| Abiha Foods Limited | Hospitality | 2022 |
| Abmc Limited | Manufacturing | 2020 |
| Abmh Ltd | Transport & logistics | 2018 |
| Above and Beyond School of Flying Ltd | Transport & logistics | 2021 |
| ABR UK Holdings Ltd | Administrative & support | 2019 |
| Absolute Sprint Ltd | Professional & scientific | 2020 |
| Abundance Logistics Limited | Administrative & support | 2025 |
| AC CLU Capital Ltd | Professional & scientific | 2024 |
| AC Electrical 4U Ltd | Construction | 2021 |
| AC Energy Assessment Ltd | Other services | 2025 |
| AC Software Systems Limited | Information & communication | 2017 |
| Ac-Risc Ltd | Professional & scientific | 2021 |
| Academiq Help Ltd | Education | 2025 |
| Academy of Mediators Limited | Education | 2025 |
| Access Biotech Consulting Ltd | Extraterritorial | 2011 |
| Access Inc Ltd | Information & communication | 2018 |
| Accident Express Rugby Ltd | Manufacturing | 2008 |
| Acclaim Construction Limited | Construction | 2014 |
| Accolade L&D UK Limited | Professional & scientific | 2020 |
| Accommodatix Ltd | Real estate | 2021 |
| Accord Partners Limited | Professional & scientific | 2010 |
| Accountability WKS Limited | Professional & scientific | 2025 |
| Accountable Solutions Limited | Information & communication | 2000 |
| Accountancy Elite Limited | Administrative & support | 2016 |
| Accounts and Tax Management Limited | Professional & scientific | 2009 |
| Accourt Limited | Professional & scientific | 2002 |
| Acdc Designs Limited | Professional & scientific | 2012 |
| Ace Digital Nest Ltd | Construction | 2025 |
| Ace Handling Limited | Extraterritorial | 2009 |
| Ace Millward Limited | Financial services | 2018 |
| Acecomp Limited | Information & communication | 1981 |
| Achoh Global Consultants Ltd | Information & communication | 2026 |
| Acier Limited | Professional & scientific | 2006 |
| ACJ Financial Planning Limited | Financial services | 2026 |
| Acmb Developments Limited | Construction | 2022 |
| Acmb Holdings Limited | Financial services | 2023 |
| Acoustic Insulations Limited | Professional & scientific | 2006 |
| Acquisitions and Development Rugby Ltd | | 2012 |
| ACS (GB) Ltd | Real estate | 2007 |
| ACS Driving Ltd | Other services | 2024 |
| ACS Transport Ltd | Transport & logistics | 2022 |
| Action Moves Logistics Ltd. | Transport & logistics | 2023 |
| Active Renovations Limited | Construction | 2025 |
| Acts of Love Investment Limited | Real estate | 2023 |
| ACU Events Limited | Arts & recreation | 2006 |
| ACUISDE2027 Ltd | Arts & recreation | 2026 |
| Acuity Property Services Limited | Hospitality | 2010 |
| AD Pharmaesthetics Ltd | Professional & scientific | 2022 |
| ADA Education Ltd | Education | 2025 |
| Adam Hiscox Legal Services Ltd | Professional & scientific | 2025 |
| Adams Technology Limited | Professional & scientific | 2016 |
| Adao Ltd | Professional & scientific | 2010 |
| Adaptive Sports Innovations (ASI) CIC | Arts & recreation | 2016 |
| Adassa Fragrances Limited | Manufacturing | 2025 |
| Addai's Enterprise UK Ltd | Wholesale & retail | 2017 |
| Adewa Limited | Real estate | 2026 |
| Adiel Limited | Transport & logistics | 2022 |
| Aditya Properties Limited | Hospitality | 2018 |
| Admirals Buildings and Roofing Ltd | Construction | 2024 |
| Adonai Ventures Limited | Financial services | 2026 |
| Adrian Davis & Associates Limited | Professional & scientific | 2012 |