| Al-Barr Automotive Limited | Wholesale & retail | 2020 |
| Al-Jabr Ltd | Education | 2025 |
| Alan House Limited | Real estate | 2016 |
| Alan Mcshee Ltd | Administrative & support | 2014 |
| Alares Limited | Professional & scientific | 2018 |
| Alderbourne (Ascot) Management Co. Limited | Households | 2006 |
| Alderverum Ltd | Professional & scientific | 2011 |
| Aldo Cars Ltd | Wholesale & retail | 2025 |
| Alex Crow Limited | Arts & recreation | 2004 |
| Alexander Chase Limited | Manufacturing | 2024 |
| Alexandra Court (Windsor) Management Company Limited | Households | 2008 |
| Alexandra Nealon Commercial Strategy Ltd | Administrative & support | 2016 |
| Alexandros Group Limited | Construction | 2018 |
| Ali's Inn Ltd | Hospitality | 2017 |
| Aliceandrose Ltd | Information & communication | 2024 |
| Alinthorn Limited | Households | 1985 |
| Alistair Buchanan Limited | Administrative & support | 2017 |
| Alive Winning Enterprises Limited | Real estate | 2024 |
| ALL Acres Limited | Professional & scientific | 2025 |
| ALL Riot Ltd | Wholesale & retail | 2011 |
| ALL Tanned UP and Ready to Glow Ltd | Extraterritorial | 2024 |
| Allen Giles Consulting Ltd | Professional & scientific | 2022 |
| Allen Giles Properties Ltd | Real estate | 2017 |
| Alliance Design and Construction Limited | Construction | 2023 |
| Allium Interior Solutions Limited | Professional & scientific | 2016 |
| Allytandron Ltd | Real estate | 2012 |
| Alpentherme Limited | Administrative & support | 2018 |
| Alpha Asbestos Solutions Ltd | Water & waste | 2025 |
| Alpha House Investment Ltd | Real estate | 2020 |
| Alphan Limited | Financial services | 2024 |
| Altaphoria Group Limited | Financial services | 2024 |
| Altaphoria Logistics Ltd | Transport & logistics | 2024 |
| Altorey Limited | Professional & scientific | 2013 |
| Altro Enterprises Ltd | Financial services | 2021 |
| Alution IT Ltd | Information & communication | 2018 |
| Always Growing Ltd | Education | 2015 |
| Alyin Properties Limited | Real estate | 2026 |
| Alyzeo Ltd | Wholesale & retail | 2017 |
| AM Groupco Ltd | Financial services | 2025 |
| Amadeus Estates Limited | Real estate | 2017 |
| Amalgamated Berkshire Developments Limited | Real estate | 2011 |
| Amalgamated Berkshire Estates Limited | Real estate | 1958 |
| Amalgamated Berkshire Holdings Limited | Real estate | 1958 |
| Amalgamated Berkshire Investments Limited | Real estate | 2011 |
| Amalgamated Berkshire Properties Limited | Real estate | 1996 |
| Amanah Property Investments Ltd | Real estate | 2025 |
| AMATO7 Limited | Hospitality | 2026 |
| Ambassadors Court and Festival Court Freehold Limited | Households | 2022 |
| Ambatec Solutions Limited | Information & communication | 2011 |
| Ambemaa Limited | Wholesale & retail | 2024 |
| Amber Vale Food Service Ltd | Wholesale & retail | 2025 |
| Amber Waterside (Cranleigh) Management Company Limited | Households | 2022 |
| American Valeting Centre Ltd | Other services | 2011 |
| AMG13 Homes Ltd | Real estate | 2025 |
| Amgames Pro Ltd | Information & communication | 2025 |
| Amica Loca Ltd | Professional & scientific | 2018 |
| Amijdn Limited | Professional & scientific | 2009 |
| Amity Residential Care Limited | Health & social care | 2007 |
| Amlik Limited | Wholesale & retail | 2025 |
| Amma's Health Care Ltd | Health & social care | 2013 |
| Amoc Properties Ltd | Real estate | 2026 |
| Amor Beverage Enterprise Holdings Limited | Wholesale & retail | 2025 |
| Amor Beverages Limited | Hospitality | 2014 |
| Amor Food and Beverages Holdings Limited | Manufacturing | 2018 |
| Amor Hydrate Limited | Hospitality | 2025 |
| Amplifyi Ltd | Wholesale & retail | 2025 |
| Amra Property Ltd | Real estate | 2025 |
| AN Adventurous World Ltd | Information & communication | 2023 |
| Anand Investments Ltd | Professional & scientific | 2013 |
| Anantalinkx Private Limited | Wholesale & retail | 2025 |
| Anchor Hygiene Services Limited | Education | 2013 |
| Anchor Media Limited | Information & communication | 2015 |
| AND Action Limited | Arts & recreation | 2017 |
| Anderburr Studios Limited | | 1976 |
| Andrew Catterall Photography Limited | Professional & scientific | 2005 |
| Andrew Mace Windows Limited | Construction | 2021 |
| Andribarr Property Ltd | Real estate | 2026 |
| Angel Automobiles Limited | Professional & scientific | 2013 |
| Angelfield Freehold Company Limited | Households | 2004 |
| Angelfield Property Management Company (1980) Limited | Households | 1980 |
| Animal Nutritionals Ltd | Manufacturing | 2020 |
| Annabells Ltd | Hospitality | 2022 |
| Anndama Ltd | Wholesale & retail | 2019 |
| Anoushka Ayurveda Limited | Health & social care | 2019 |
| Anra Deals Ltd | Wholesale & retail | 2019 |
| Anrom Limited | Construction | 2023 |
| Ansh Asset Holdings Ltd | Real estate | 2024 |
| Ansh Gifts & Souvenirs Ltd | Wholesale & retail | 2024 |
| Anshika Enterprises UK Limited | Wholesale & retail | 2025 |
| Antalya Food and Catering Ltd | Hospitality | 2023 |
| Antalya Grill and Bar Ltd | Hospitality | 2020 |
| Antek Solutions Limited | Information & communication | 2007 |
| Antelope Entertainment Limited | Information & communication | 2000 |
| Antrobus Solutions Limited | Professional & scientific | 2019 |
| Antsara Investments Limited | Real estate | 2017 |
| Anushia Reddy Limited | Administrative & support | 2016 |
| Anza Properties Ltd | Construction | 2023 |
| AO Projects Limited | Construction | 2021 |
| Apex Heating Academy Ltd | Education | 2026 |
| Apex Smile Dent Limited | Health & social care | 2026 |