| Aera Performance Limited | Arts & recreation | 2025 |
| Aerogen Holdings Limited | Financial services | 2013 |
| Aerogen Limited | Extraterritorial | 2011 |
| Afcw (BP) Ltd | Wholesale & retail | 2019 |
| Afish Limited | Wholesale & retail | 2023 |
| African Solutions UK | Other services | 2013 |
| African Soul Ltd | Professional & scientific | 2021 |
| Agile Business Solutions Limited | Professional & scientific | 2003 |
| Agilis Quality Services Ltd | Professional & scientific | 2015 |
| Agropharm Holdings Limited | Manufacturing | 2008 |
| Agropharm Limited | Wholesale & retail | 1974 |
| AGT Supplies Limited | Wholesale & retail | 2022 |
| AI Task Network Ltd | Information & communication | 2026 |
| Air Conditioning & Refrigeration Ltd | Energy | 2025 |
| Air Parts Global Limited | Wholesale & retail | 2019 |
| Airsafe Analytical Limited | Construction | 2008 |
| Airsafe Developments Ltd | Construction | 2016 |
| Airsafe Surveys Limited | Professional & scientific | 2009 |
| Airsource Climate Ltd | Energy | 2020 |
| AJG Grantchester Associates Ltd | Professional & scientific | 2015 |
| AJS Design & Build Limited | Construction | 2026 |
| AKB Design Limited | Professional & scientific | 2014 |
| Akru Group Limited | Professional & scientific | 2020 |
| Alaco Property Management Ltd | Real estate | 2019 |
| Alan Murphy Racing Ltd | Wholesale & retail | 2018 |
| Albemarle Avebury Ltd | Real estate | 2018 |
| Albemarle Property Holdings Ltd | Construction | 2017 |
| Albemarle Riverside Ltd | Financial services | 2019 |
| Albion Investments & Holdings Ltd | Real estate | 2014 |
| Alcalay Consulting Ltd | Professional & scientific | 2021 |
| Alcomb Care Limited | Public administration | 2025 |
| Alderhurst Holdings Limited | Financial services | 2026 |
| Aldersey Advisers Limited | Professional & scientific | 2010 |
| Aldershot Cadrive Ltd | Administrative & support | 2024 |
| Aled Lewis Studio Ltd | Arts & recreation | 2012 |
| Alejos & Jones Developments Ltd | Real estate | 2026 |
| Alesbury Cadrive Ltd | Administrative & support | 2024 |
| Alex-Perry.Com Limited | Arts & recreation | 2014 |
| Alexander House Rentals Limited | Hospitality | 2011 |
| Alianis Limited | Professional & scientific | 2002 |
| Alibaba Eats Ltd | Hospitality | 2021 |
| Aligned Wellness Ltd | Health & social care | 2024 |
| Alineapart Ltd | Arts & recreation | 2020 |
| ALL Aspects Financial Planning Limited | Financial services | 2020 |
| ALL Things to ALL MEN Limited | Information & communication | 2011 |
| Allen Associates Limited | Professional & scientific | 2004 |
| Allwright Projects Limited | Construction | 2015 |
| Alma Petrophysical & Geological Consulting Ltd | Professional & scientific | 2014 |
| Alonissos Programs Limited | Information & communication | 2005 |
| Alpha Computing (UK) Ltd | Information & communication | 1996 |
| Alpha Fire & Electrical Services Limited | Construction | 2025 |
| Alphaville Properties Limited | Real estate | 2022 |
| Alpia Ltd | Information & communication | 2011 |
| Alprange Communications Limited | Information & communication | 1997 |
| Alresford & District Agricultural Society Limited | Other services | 1988 |
| Alresford Events Ltd | Administrative & support | 2019 |
| Alresford Service Point Ltd | Wholesale & retail | 2022 |
| Altekgo Limited | Financial services | 2023 |
| Alternative Packaging Solutions Limited | Wholesale & retail | 1996 |
| Alton Arts Festival CIC | Arts & recreation | 2023 |
| Alton Bolt & Tool Co. Limited | Wholesale & retail | 1983 |
| Alton Brewing Heritage Trail CIC | Arts & recreation | 2024 |
| Alton Business Centre (NO2) Management Association Limited | Real estate | 1992 |
| Alton Business Centre Management Association Limited | Extraterritorial | 1990 |
| Alton Car Service Centre Limited | Wholesale & retail | 2013 |
| Alton Catering Ltd | Hospitality | 2018 |
| Alton Christian Care Ltd | Other services | 2012 |
| Alton Community BUS Ltd | Transport & logistics | 2019 |
| Alton Community Cupboard Ltd | Hospitality | 2021 |
| Alton Cricket Club C.I.C. | Arts & recreation | 2025 |
| Alton Fish and Chips Limited | Hospitality | 2021 |
| Alton Glass Limited | Wholesale & retail | 2010 |
| Alton Gold Buyers Limited | Wholesale & retail | 2009 |
| Alton Hearing Care Ltd | Wholesale & retail | 2019 |
| Alton Islamic Centre Ltd | Education | 2018 |
| Alton Maltings Centre Community Interest Company | Administrative & support | 2007 |
| Alton Marine Consulting Limited | Transport & logistics | 2024 |
| Alton Masonic Centre Ltd | Other services | 2023 |
| Alton Masonic Centre Management Ltd | Other services | 2023 |
| Alton Nails TD Ltd | Other services | 2025 |
| Alton Pain Clinic Ltd | Health & social care | 2020 |
| Alton Paint & Panel Ltd | Wholesale & retail | 2015 |
| Alton Tailoring Services Limited | Other services | 2024 |
| Alton Valeting Centre Ltd | Administrative & support | 2020 |
| Alton Valeting Ltd | Administrative & support | 2026 |
| Alton Vehicle Hire Ltd | Administrative & support | 2008 |
| Alton White Hart Community Interest Company | Hospitality | 2014 |
| Altonian Business Consultants Limited | Professional & scientific | 2026 |
| Altonian Care Ltd | Health & social care | 2013 |
| Alton’S Bakers Arms Ltd | Hospitality | 2024 |
| Altotel Ltd | Information & communication | 2026 |
| Altrincham (T2) Hairdressing Limited | Other services | 2016 |
| AM & PM Catering (Country) Limited | Hospitality | 1998 |
| Amaryllis Accountancy and Business Services Ltd | Professional & scientific | 2016 |
| Amaryllis Bridal Boutique Limited | Wholesale & retail | 2017 |
| Amber Environmental Limited | Professional & scientific | 2018 |
| Amber Pumpkin Limited | Wholesale & retail | 2010 |
| Amberley Mews Management Company Limited | Households | 2002 |
| Amery Hill School Academy Trust | Education | 2011 |
| Amir Savage Limited | Health & social care | 2012 |