| A&S Executive Foods Ltd | Hospitality | 2024 |
| A&S Private Limited | Information & communication | 2018 |
| A&V Fast Trans Ltd | Transport & logistics | 2025 |
| A&V Joinery Ltd | Construction | 2026 |
| A&W Management MK Ltd | Hospitality | 2026 |
| A-Kus RMN Limited | Health & social care | 2020 |
| A-Lectrical Solutions Ltd | Construction | 2023 |
| A-Med Systems Limited | Information & communication | 2001 |
| A-Rajah Holdings Limited | Real estate | 2026 |
| A-Tek Engineering Limited | Professional & scientific | 2020 |
| A-Wd Web Design Ltd | Information & communication | 2024 |
| A.C.N. Electrical Services Limited | Construction | 2016 |
| A.E.C. Limited | Manufacturing | 2022 |
| A.F.M.M Global Ltd | Real estate | 2015 |
| A.Gallani Ltd | Construction | 2021 |
| A.H. Cargo and Clearing UK Ltd | Transport & logistics | 2021 |
| A.I Capital & Invest Ltd | Wholesale & retail | 2023 |
| A.J. Pauley Developments Limited | Construction | 1998 |
| A.J.W. Motorcycles Limited | Arts & recreation | 2003 |
| A.M. Craig Limited | Extraterritorial | 1949 |
| A.N. Sourcing UK Ltd | Wholesale & retail | 2021 |
| A.O.U.G. Foundation for Education | Education | 1994 |
| A.O.U.G. Trading Limited | Wholesale & retail | 1994 |
| A.P.O Homes Ltd | Real estate | 2024 |
| A.P.X. Limited | Construction | 1992 |
| A.S.P. Farming Limited | Agriculture & fishing | 2004 |
| A.W.R. Pickersgill Limited | Construction | 1982 |
| A1 Carpet Cleaning Ltd | Administrative & support | 2020 |
| A1 Drain Solutions Limited | Construction | 2012 |
| A1 Sign Services Limited | Administrative & support | 2009 |
| A11 Property Investments Ltd | Real estate | 2024 |
| A1M Limited | Wholesale & retail | 2025 |
| A2 Beauty Limited | Other services | 2022 |
| A2 Design Shed Ltd | Professional & scientific | 2023 |
| A2 Innovations Ltd | Professional & scientific | 2020 |
| A2B Agency Ltd | Information & communication | 2024 |
| A2B Remove ALL Limited | Transport & logistics | 2024 |
| A2D Pro Ltd. | Professional & scientific | 2014 |
| A2S' Studio Ltd | Wholesale & retail | 2024 |
| A2Z Accountancy Ltd | Professional & scientific | 2020 |
| A2Z Trendz Ltd | Wholesale & retail | 2025 |
| A3R Rastogi Limited | Real estate | 2026 |
| A4 London Limited | Hospitality | 2022 |
| A4G BE Visible Ltd | Professional & scientific | 2018 |
| A5 Electrical Limited | Construction | 2020 |
| A5H Plumbing Ltd | Construction | 2021 |
| A@Z Computing Limited | Manufacturing | 2011 |
| AA and AK Properties Ltd | Real estate | 2018 |
| AA Commercial BIN Cleaning Ltd | Administrative & support | 2024 |
| AA Derma Clinic Ltd | Health & social care | 2022 |
| AA Executive Taxis Ltd | Transport & logistics | 2023 |
| AA Fuel Ltd | Wholesale & retail | 2025 |
| AA Infotech Limited | Information & communication | 2023 |
| AA Music Limited | Education | 2023 |
| AA Offlicence Limited | Wholesale & retail | 2022 |
| AA Plumbing Needs Ltd | Construction | 2025 |
| AA Recycling Ltd | Water & waste | 2018 |
| AA Services MK Ltd | Professional & scientific | 2025 |
| AA Tech MK Ltd | Professional & scientific | 2023 |
| AA TRANSPORT19 Ltd | Administrative & support | 2023 |
| AA09 Ltd | Financial services | 2023 |
| AAA Brothers Limited | Wholesale & retail | 2014 |
| AAA Innovative Properties Limited | Real estate | 2024 |
| AAA Royale Drinks Ltd | Wholesale & retail | 2025 |
| Aaac Holdings Limited | Financial services | 2025 |
| Aaarch Tech Ltd | Information & communication | 2024 |
| Aaav Property Ltd | Households | 2023 |
| AAB & Co UK Limited | Health & social care | 2018 |
| AAB Infotech Ltd | Information & communication | 2015 |
| Aabacus Training Limited | Professional & scientific | 2006 |
| Aabe Edutainment Ltd | Education | 2019 |
| Aabe Finances Ltd | Real estate | 2025 |
| Aadhna Private Ltd | Health & social care | 2024 |
| Aadiastore Ltd | Wholesale & retail | 2025 |
| Aadya Corp. Ltd | Information & communication | 2015 |
| Aadya Homes Limited | Real estate | 2020 |
| AAE Ukproperty Limited | Real estate | 2023 |
| AAH Group Limited | Wholesale & retail | 2025 |
| Aaic Ltd | Construction | 2026 |
| Aajom Properties Ltd. | Real estate | 2017 |
| AAK Funding Ltd | Financial services | 2022 |
| Aali G Limited | Professional & scientific | 2025 |
| Aamadevi Limited | Administrative & support | 2024 |
| Aamico Limited | Information & communication | 2015 |
| Aamir Beading London Ltd | Manufacturing | 2020 |
| AAR Technologies Ltd | Information & communication | 2010 |
| Aardvark Property Services (Milton Keynes) Ltd | Construction | 2018 |
| Aardwolf Security Ltd | Information & communication | 2015 |
| Aari IT Services Limited | Information & communication | 2016 |
| Aarish Properties Ltd | Real estate | 2021 |
| Aark Properties Limited | Real estate | 2018 |
| Aarkian Limited | Real estate | 2022 |
| Aarkian Properties LLP | | 2019 |
| Aarna Connect Tech Services Ltd | Information & communication | 2023 |
| Aaron IS Love Ltd | Health & social care | 2022 |
| Aaron Millar Associates Limited | Professional & scientific | 1998 |
| Aaron Wallis Recruitment & Training Limited | Administrative & support | 2007 |
| Aaron&Co Ltd | Professional & scientific | 2022 |
| Aaronks UK Limited | Real estate | 2023 |
| Aarush Housing Ltd | Real estate | 2023 |