| AA Medical Enterprise Ltd | Health & social care | 2019 |
| Aa.Sandhu Investments Ltd | Real estate | 2020 |
| Aatta Ltd | Real estate | 2024 |
| ABA International Touring (UK) Ltd. | Arts & recreation | 2016 |
| Abacus Brands Limited | Wholesale & retail | 2021 |
| Abacus Enviro Ltd | Water & waste | 2026 |
| Abailin Limited | Wholesale & retail | 2012 |
| Abbey International Ltd | Wholesale & retail | 2015 |
| Abbey Place Mews (Warfield) Management Co Ltd | Households | 2022 |
| ABC Professionals LLP | | 2021 |
| Abi-Loi Limited | Professional & scientific | 2024 |
| Abingworth Meadows Management Company Limited | Households | 2015 |
| Abn'G World Ltd | Arts & recreation | 2024 |
| About Change Limited | Professional & scientific | 2003 |
| Above and Beyond Gardens Ltd | Construction | 2013 |
| Abwts | Education | 2011 |
| AC Grips Limited | Information & communication | 2013 |
| Acacia House, Acacia Mews Limited | Households | 1997 |
| Acacia Mews Management Limited | Households | 1986 |
| Access in Mind Limited | Other services | 2025 |
| Accountancy Support Limited | Professional & scientific | 1995 |
| Accountants for Landlords Limited | Professional & scientific | 2025 |
| Accounttax (Services) Ltd | Professional & scientific | 2020 |
| Accu LET Ltd | Real estate | 2024 |
| Accurvis Ltd | Information & communication | 2026 |
| Ace Interior Solutions Ltd | Arts & recreation | 2012 |
| Ace Martial Arts Limited | Arts & recreation | 2022 |
| ACF Services Ltd | Construction | 2016 |
| ACF Wallis Holdings Ltd | Real estate | 2022 |
| ACG Joint Company Limited | Construction | 2006 |
| ACJ Global Connections Ltd | Information & communication | 2021 |
| Acme Family Investments Limited | Financial services | 2025 |
| Acquire Property Partners Ltd. | Real estate | 2025 |
| Acquirement Limited | Real estate | 2023 |
| Acre Passage Management Company Limited | Households | 2013 |
| ACS Associates Ltd | Information & communication | 2012 |
| Active Solutions (Windsor) Limited | Information & communication | 2017 |
| Acton Street Freehold Ltd | Other services | 2016 |
| Acuity Analytica Ltd | Professional & scientific | 2024 |
| Acuity Marketing Consulting Ltd | Professional & scientific | 2018 |
| Adam and Khan Limited | Professional & scientific | 2026 |
| Adam Strong Consulting Ltd | Professional & scientific | 2014 |
| Adcept Ltd | Professional & scientific | 2023 |
| Addikt Solutions Ltd | Information & communication | 2024 |
| Addison RD RL Ltd | Real estate | 2023 |
| Additives Ltd | Professional & scientific | 2025 |
| ADITA5 Limited | Transport & logistics | 2018 |
| Adiva’S Clinic Ltd | Other services | 2025 |
| ADL Marine Ltd | Wholesale & retail | 2025 |
| Admac Consultancy Services Ltd | Information & communication | 2024 |
| Adoptx Ltd | Information & communication | 2024 |
| Adore 2 Care Ltd | Administrative & support | 2019 |
| Adorn Stoneware Ltd | Manufacturing | 2007 |
| ADP Build Ltd | Construction | 2020 |
| ADP Homes Ltd | Construction | 2025 |
| Adsm Trustees Limited | Extraterritorial | 2009 |
| Advanced Demand Side Management Limited | Water & waste | 1992 |
| Advanced Retirement Living Limited | Extraterritorial | 2014 |
| Adventure Golf Holdings Ltd | Financial services | 2017 |
| Advertising Artists Ltd | Wholesale & retail | 2019 |
| Advertising Health Ltd | Information & communication | 2026 |
| Advisory Associates Ltd | Information & communication | 2014 |
| Adyoulike Limited | Information & communication | 2010 |
| AFA Car Sales Ltd | Wholesale & retail | 2022 |
| AFA Property Services Ltd | Real estate | 2022 |
| AFA Wholesale Ltd | Wholesale & retail | 2023 |
| AFC Direct Ltd | Wholesale & retail | 2016 |
| Afce Ltd | Manufacturing | 2021 |
| African Conservation Finance Limited | Households | 2022 |
| AG Consultancy & Apps Ltd | Information & communication | 2007 |
| AGA by Adrian Limited | Construction | 2025 |
| Agam Capital Limited | Hospitality | 2021 |
| Agasya Infotech Limited | Information & communication | 2018 |
| AGD Construction Services Limited | Construction | 2017 |
| Aghor Ltd | Information & communication | 2023 |
| Agipro Ltd | Financial services | 2020 |
| Ahah! Consulting UK Ltd | Information & communication | 2021 |
| AHN MD Property Limited | Real estate | 2021 |
| Ahura Virtual Audio (AVA) Limited | Manufacturing | 2016 |
| Ahura Wellness Innovations Limited | Information & communication | 2022 |
| AI Associates Ltd | Professional & scientific | 2020 |
| Aibidia UK Limited | Professional & scientific | 2022 |
| AIE Expertise Ltd | Professional & scientific | 2023 |
| Aiiniia Ltd | Professional & scientific | 2021 |
| Ailehpo Capital Ltd | Financial services | 2023 |
| AIM2AID Limited | Education | 2025 |
| Aimrai Smart Limited | Information & communication | 2025 |
| Aimwise Limited | Professional & scientific | 2002 |
| Airee Group Ltd | Construction | 2025 |
| Ajana Limited | Health & social care | 2007 |
| AJD1CONSULTING Limited | Construction | 2016 |
| Ajdt Limited | Administrative & support | 2022 |
| AK & Sons Property Management Ltd | Real estate | 2021 |
| AK Toben Limited | Real estate | 2024 |
| AKA Accountants Limited | Professional & scientific | 2021 |
| Aktivus Limited | Professional & scientific | 2010 |
| AL Fassia Restaurant Ltd | Hospitality | 2018 |
| AL Hamid Investments Ltd | Financial services | 2024 |
| AL Naseeb Estates Ltd | Households | 2025 |
| AL Rayaz Investment & Financial Management Services Ltd | Financial services | 2023 |