| Abode Homes (Maresfield Park) Ltd | Real estate | 2021 |
| Abode Land Ltd | Real estate | 2020 |
| Abode Middleton (Management Co) Ltd | Real estate | 2021 |
| Abode Well Design and Build Ltd | Wholesale & retail | 2024 |
| About Time Aviation Ltd | Professional & scientific | 2025 |
| Abraxas Maritime Ltd | Transport & logistics | 2007 |
| Absolut Care Ltd | Health & social care | 2017 |
| Absolute Land Limited | Real estate | 2023 |
| Absolute Promotions Limited | Manufacturing | 2003 |
| Abstract Space Limited | Information & communication | 2024 |
| Abtv Ltd | Information & communication | 2021 |
| AC & AA Limited | Administrative & support | 2018 |
| AC TEC Ltd | Real estate | 2017 |
| Academus Consulting Ltd | Professional & scientific | 2026 |
| Acanthion Ltd | Wholesale & retail | 2019 |
| Acarya Ltd | Professional & scientific | 2018 |
| Acbiggs Ltd | Health & social care | 2023 |
| Access Arts TW CIC | Education | 2024 |
| Accordia Mortgages Ltd | Financial services | 2016 |
| Accountancy & Taxation Centre Limited | Extraterritorial | 2021 |
| Ace Consult Ltd | Professional & scientific | 2024 |
| Ace Dwellings Ltd | Real estate | 2022 |
| Ace India Limited | Health & social care | 2007 |
| Acer Building Services Limited | Construction | 2011 |
| Achieve Green Limited | Professional & scientific | 2009 |
| Achieve Success Coaching Ltd | Education | 2024 |
| Achieve UK Consulting Ltd | Professional & scientific | 2024 |
| Achieving Action Ltd | Professional & scientific | 2025 |
| Achor Employment Law Consulting Ltd | Professional & scientific | 2012 |
| Achristo Solutions Ltd | Professional & scientific | 2011 |
| Aclg Limited | Financial services | 2024 |
| ACM Broking Limited | Financial services | 1999 |
| Acme Bioscience Services Limited | Professional & scientific | 2021 |
| Acorn AI Ltd | Information & communication | 2024 |
| Acorn Homes (Southern) Limited | Real estate | 1995 |
| Acot Construction Ltd | Construction | 2025 |
| Acquitain Limited | Administrative & support | 2014 |
| ACR Property Limited | Real estate | 2007 |
| Acre Art Limited | Financial services | 2024 |
| Acre Capital Holdings LLP | | 2020 |
| Acre Capital Properties LLP | | 2023 |
| Acre Capital Real Estate Holdings Limited | Extraterritorial | 2023 |
| Acre Property Consultants Limited | Extraterritorial | 2023 |
| ACTIV8 Mktg Ltd | Professional & scientific | 2024 |
| Active Babies Ltd | Wholesale & retail | 2022 |
| Adam Kershaw Ltd | Manufacturing | 2015 |
| Adams Real Estate Limited | Real estate | 2001 |
| Adana 68 Limited | Hospitality | 2022 |
| Adems Transport Ltd | Transport & logistics | 2024 |
| Adhd & Autism Associates LLP | | 2025 |
| Adina Chemicals Limited | Extraterritorial | 2019 |
| Adina Cosmetic Ingredients Limited | Wholesale & retail | 1991 |
| Adler Fairways Insurance Brokers Limited | Financial services | 2002 |
| Adler Fairways Insurance Group Limited | Financial services | 2016 |
| ADM Coaching Ltd | Information & communication | 2021 |
| ADM Connex Ltd | Construction | 2022 |
| Adoor Ltd | Information & communication | 2019 |
| Adrian Day Advisers Limited | Professional & scientific | 2010 |
| Adsthetics Ltd | Professional & scientific | 2025 |
| Adsum Auxilium Limited | Extraterritorial | 1999 |
| Advance Drywall Limited | Construction | 2016 |
| Advanced Capability (UK) Limited | Information & communication | 2013 |
| Advanced Capability Solutions Limited | Professional & scientific | 2012 |
| Advanced Chrome Design LLP | | 2009 |
| Advanced MED Tech Ltd | Wholesale & retail | 2023 |
| Advento Staffing Limited | Administrative & support | 2011 |
| Adventures in Motion Ltd | Administrative & support | 2017 |
| Advertainment Media Limited | Information & communication | 2014 |
| ADVICE2U Ltd | Financial services | 2022 |
| Advocacy and Mediation Associates Ltd | Other services | 2025 |
| Advocate Events & Tours Ltd | Administrative & support | 2024 |
| Adwerth LLP | | 2009 |
| Aec.Electrical Limited | Construction | 2016 |
| AEG Consultancy Services Ltd | Professional & scientific | 2015 |
| Aegean Spirits Ltd | Wholesale & retail | 2025 |
| AEJ Projects International Ltd | Manufacturing | 2016 |
| AEJ Projects Limited | Manufacturing | 1995 |
| Aemp Limited | Arts & recreation | 2006 |
| Aeonian Foods Limited | Hospitality | 2019 |
| Aeonian Holdings Limited | Financial services | 2020 |
| Aeonian Stone Limited | Manufacturing | 2020 |
| AEP Services Limited | Information & communication | 2022 |
| Aerem Limited | Manufacturing | 2000 |
| Aeris Building Solutions Ltd | Construction | 2025 |
| Aerlume Limited | Wholesale & retail | 2025 |
| Aesthetic Features Limited | Wholesale & retail | 2024 |
| Aetheria Relocation Ltd | Real estate | 2025 |
| Aethic Ltd | Manufacturing | 2007 |
| AEV Design & Development Ltd | Professional & scientific | 2024 |
| Affinity Homes Ltd | Construction | 2018 |
| Afia Limited | Manufacturing | 2000 |
| Afrifa Advisers UK Ltd | Information & communication | 2014 |
| Afro Frizzy Hair Limited | Other services | 2015 |
| Agacia Care Ltd | Health & social care | 2021 |
| AGE UK Tunbridge Wells | Health & social care | 2012 |
| Agency Nation Limited | Professional & scientific | 2023 |
| Agentic AI Amro Ltd | Professional & scientific | 2025 |
| Agile Alex Ltd | Professional & scientific | 2023 |
| Agile Byron Consulting Ltd | Information & communication | 2025 |
| Agile Construction Management Limited | Professional & scientific | 2022 |