| Allen’S Plumbing and Heating Ltd | Construction | 2022 |
| Alliance Technical Building Services Limited | Construction | 2015 |
| Allman Properties Ltd | Real estate | 2024 |
| Alpha Electrical Contractors (Doncaster) Limited | Construction | 2018 |
| Alto Insurance Group Ltd | Financial services | 2012 |
| Altus 3.2 Limited | Professional & scientific | 2026 |
| Aluminium Rainwater Systems Ltd | Manufacturing | 2025 |
| AM Roofing Services Limited | Construction | 2012 |
| Amaze Beauty and Training Ltd | Education | 2026 |
| Amblers Mill Limited | Professional & scientific | 2010 |
| Amco Distributors Limited | Wholesale & retail | 1995 |
| Amir’S Balti House Ltd | Hospitality | 2020 |
| AMK Retford Limited | Professional & scientific | 2020 |
| Amphisoft Ltd | Information & communication | 2023 |
| Amraj Limited | Hospitality | 2004 |
| Amraj Property Ltd | Real estate | 2024 |
| Anchorbloc Limited | Manufacturing | 2009 |
| Andeira Ltd | Real estate | 2024 |
| Andrea Mclaren Ltd | Professional & scientific | 2009 |
| Andrew Hollingsworth Consultancy Services Limited | Transport & logistics | 2023 |
| Andrew Russell & Co Limited | Professional & scientific | 2006 |
| Andrew Russell Limited | Financial services | 2018 |
| Andy Brown Lettings LLP | | 2021 |
| Andy Wyld Ltd | Construction | 2011 |
| Angel Tatau Ltd | Other services | 2022 |
| Angelprime Limited | Real estate | 1993 |
| ANH Practitioner Services Limited | Health & social care | 2023 |
| Anthony Credland Engineering Services Limited | Construction | 2021 |
| Antioch Training Centre C.I.C. | Education | 2020 |
| Antony Olivier Limited | Wholesale & retail | 2026 |
| Antony Scott Ltd | Wholesale & retail | 2015 |
| ANY Motor Home Ltd | Wholesale & retail | 2026 |
| Anyon and Co. Limited | Construction | 1962 |
| Anyon Developments Limited | Other services | 2013 |
| APB Home Sales and Lettings Ltd | Real estate | 2025 |
| APE Event Hire Limited | Hospitality | 2019 |
| Apex Activ Limited | Arts & recreation | 2015 |
| Apex Aesthetics by LIV Ltd | Other services | 2025 |
| Apex International (UK) Limited | Manufacturing | 2004 |
| Apex International Limited | Extraterritorial | 2015 |
| Apex Organisation Limited | Extraterritorial | 2018 |
| APN Developments Limited | Real estate | 2005 |
| Apollo Finance Ltd. | Extraterritorial | 2016 |
| Apollo IT Transformation Ltd | Information & communication | 2022 |
| Appleton Shaw Limited | Real estate | 2010 |
| Aqua Technics Limited | Real estate | 2011 |
| Aquantima Ltd | Information & communication | 2010 |
| Aquatic Control Engineering Limited | Manufacturing | 1995 |
| Aquiko Limited | Manufacturing | 2024 |
| AR Welding & Motorsport Ltd | Manufacturing | 2023 |
| Archfinish Limited | Manufacturing | 2025 |
| Argent Financial Consultancy Limited | Other services | 2004 |
| Argyle Interiors Limited | Wholesale & retail | 1981 |
| Aries Commercial Machinery Limited | Wholesale & retail | 1993 |
| Aries Group Limited | Construction | 1996 |
| Aries Internet Limited | Information & communication | 1997 |
| Aries Marketing Limited | Information & communication | 1992 |
| Arlington Insurance Services Limited | Financial services | 2005 |
| ARM Retford Limited | Construction | 2024 |
| Armas Consultants Ltd | Administrative & support | 2022 |
| Armstrong Evans Ltd | Administrative & support | 2010 |
| Arnold Brown Logistics Limited | Transport & logistics | 2010 |
| ARO Welding Technologies Limited | Wholesale & retail | 1987 |
| Arrian Creative Innovations Limited | Professional & scientific | 2023 |
| Arrow Build Limited | Construction | 2010 |
| ASA Residential Properties Ltd | Real estate | 2026 |
| Asar Betts Limited | Real estate | 2021 |
| Asbestos Surveillance Limited | Professional & scientific | 2014 |
| Asbestos Surveying Limited | Professional & scientific | 2004 |
| Ashall Care (Barnby Moor) Ltd | Health & social care | 2021 |
| Ashall Care Ltd | Health & social care | 2013 |
| Ashley Carter (Lincoln) Limited | Arts & recreation | 2003 |
| Ashley House Residential Ltd | Real estate | 2018 |
| Ashton Poole Hair Studio Limited | Other services | 2024 |
| Ashton Ventures Ltd | Wholesale & retail | 2026 |
| Ashvale Services Limited | Extraterritorial | 2016 |
| ASK Electrotec Limited | Construction | 2008 |
| Asteria Engine Ltd | Information & communication | 2025 |
| AT the Vaults Limited | Real estate | 2021 |
| Atherton Conveyor Spares Limited | Manufacturing | 2019 |
| Atherton Holdings Limited | Financial services | 2015 |
| Atherton Materials Handling Limited | Manufacturing | 2009 |
| Atherton Plant Limited | Administrative & support | 2015 |
| Atlas Holdings & Investments Ltd | Financial services | 2019 |
| Atlas Promotions Limited | Administrative & support | 2012 |
| ATW Energy Solutions Ltd | Construction | 2022 |
| Atwood Benefits UK Limited | Financial services | 2005 |
| Auckley Parish Centre | Other services | 2015 |
| Auction World Limited | Wholesale & retail | 2013 |
| Aurora House Developments Limited | Construction | 2021 |
| Autopeople Limited | Extraterritorial | 2008 |
| Available Health Group Ltd | Professional & scientific | 2026 |
| Available Health Ltd | Health & social care | 2019 |
| Avalon Kicks Ltd | Manufacturing | 2019 |
| Avanti Steel Fabrications Limited | Construction | 1991 |
| B & B Entertainment (Bridge Street) Limited | Hospitality | 2024 |
| B & B Entertainment Limited | Hospitality | 2023 |
| B and P Unique Services Limited | Real estate | 2021 |
| B I F Services Limited | Construction | 1998 |
| B Longden Plumbing and Heating Limited | Construction | 2026 |