| Ashabel Limited | Information & communication | 2023 |
| Ashan Food Ltd | Hospitality | 2025 |
| Ashbourne Day Nurseries Limited | Education | 2008 |
| Ashbourne Healthcare Limited | Health & social care | 2015 |
| Ashbourne Surgical Limited | Professional & scientific | 2015 |
| Ashbrook Holdings Ltd | Financial services | 2018 |
| Ashbrook Timber Manufacturing & Supply Ltd | Manufacturing | 2025 |
| Ashby Park Management Company Limited | Real estate | 1995 |
| Ashby, Gorman Baker Ltd | Professional & scientific | 1995 |
| Ashcroft Autocare Limited | Wholesale & retail | 2024 |
| Ashdown Hurrey (Holdings) Limited | Professional & scientific | 1993 |
| Asher & Co Limited | Real estate | 1995 |
| Ashes Barns Development Limited | Construction | 2024 |
| Ashfla Limited | Administrative & support | 2015 |
| Ashford Court Management Limited | Extraterritorial | 2007 |
| Ashgate Developments Limited | Administrative & support | 2001 |
| Ashka Holdings Limited | Financial services | 2025 |
| Ashland (MK) Management Company NO.1 Limited | Households | 2023 |
| Ashland Coffee & Crumbs Ltd | Hospitality | 2026 |
| Ashland Engineering Ltd | Manufacturing | 2010 |
| Ashland MK Limited | Hospitality | 2025 |
| Ashley Allie Limited | Manufacturing | 2024 |
| Ashley Associates Limited | Construction | 2002 |
| Ashley Madison Limited | Information & communication | 2010 |
| Ashley Manor Upholstery Limited | Manufacturing | 1993 |
| Ashlotrimcare Ltd | Health & social care | 2018 |
| Ashmina Ltd | Wholesale & retail | 2021 |
| Ashraf IT Consultants Ltd | Administrative & support | 2011 |
| Ashrey Properties Ltd | Real estate | 2024 |
| Ashron Consulting Limited | Administrative & support | 2006 |
| Ashsons Property Limited | Real estate | 2022 |
| Ashstone Property Services Limited | Real estate | 2013 |
| Ashtavinayak Ltd | Health & social care | 2012 |
| ASI Solutions Limited | Construction | 2003 |
| Asian Community Radio Ltd | Information & communication | 2023 |
| Asiko Collections Limited | Financial services | 2015 |
| Asir Tech GB Ltd | Information & communication | 2016 |
| Asirvad Residentials Limited | Real estate | 2016 |
| ASK D.T. Ltd | Information & communication | 2021 |
| ASK Electricare Ltd | Construction | 2025 |
| ASK Goto Limited | Professional & scientific | 2017 |
| ASK Itech Solutions Limited | Information & communication | 2017 |
| ASK RAM Limited | Professional & scientific | 2024 |
| ASK Rent Limited | Real estate | 2020 |
| ASK UK Consultants Ltd | Professional & scientific | 2022 |
| ASK UK Property Limited | Real estate | 2023 |
| Aska Accountants Ltd | Professional & scientific | 2025 |
| Askcap Limited | Wholesale & retail | 2019 |
| Askdrt Limited | Professional & scientific | 2020 |
| Askp UK Consultants Ltd | Professional & scientific | 2025 |
| ASL Lettings Limited | Real estate | 2020 |
| ASL Propertyuk Ltd | Real estate | 2022 |
| Aslan Psychology Ltd | Health & social care | 2021 |
| ASM Catering Ltd | Hospitality | 2025 |
| Asmarina Limited | Construction | 2011 |
| Asmview Softtech Limited | Information & communication | 2022 |
| ASN Consultancy (UK) Ltd | Information & communication | 2013 |
| ASN Hospitality & Events Ltd | Administrative & support | 2024 |
| Asox Limited | Information & communication | 2019 |
| Aspect Accountancy Ltd | Professional & scientific | 2014 |
| Aspect SME Limited | Information & communication | 2024 |
| Aspen Accounting Associates Ltd | Professional & scientific | 2003 |
| Aspen Consultants (U.K.) Limited | Information & communication | 1995 |
| Aspen Court Freehold Management Limited | Households | 2016 |
| Aspenlea Ltd | Administrative & support | 2025 |
| Aspexx Homes Ltd | Construction | 2020 |
| Aspire Analytics Limited | Information & communication | 2024 |
| Aspire Dental Clinic Ltd | Health & social care | 2006 |
| Aspire Financial Group Limited | Professional & scientific | 2020 |
| Aspire Horizons Limited | Education | 2025 |
| Aspire Intellect Ltd | Administrative & support | 2025 |
| Aspire Memoria Ltd | Health & social care | 2015 |
| Aspire Merchandising Ltd | Other services | 2018 |
| Aspire Presenting Limited | Information & communication | 2012 |
| Aspire Roofing Specialists Ltd | Construction | 2022 |
| Aspire Towers Limited | Real estate | 2023 |
| Aspired Care Services Limited | Public administration | 2021 |
| Aspiremedia Productions Limited | Arts & recreation | 2014 |
| Aspley Commercial Ltd | Administrative & support | 2023 |
| Aspley Flooring Limited | Construction | 2008 |
| Aspley Foods (Olney) LLP | | 2009 |
| Aspley Guise and Woburn Sands Golf Club Limited | Arts & recreation | 1953 |
| Aspley Heath Books Limited | Professional & scientific | 2025 |
| Aspley Heath Limited | Professional & scientific | 2022 |
| Aspley Heath Property Limited | Real estate | 2024 |
| Aspurian Digital Limited | Information & communication | 2017 |
| Aspurian Ltd | Professional & scientific | 2010 |
| Aspyre Travel Ltd | Administrative & support | 2023 |
| ASR Painters & Decorators Ltd | Construction | 2018 |
| ASR Properties Investment Limited | Construction | 2025 |
| Asryan Ltd | Construction | 2017 |
| Assam MK Ltd | Wholesale & retail | 2024 |
| Assencorp Ltd | Wholesale & retail | 2013 |
| Assertive Media Solutions Ltd | Information & communication | 2012 |
| Assessment Inspection Services LLP | | 2025 |
| Asset Investors Limited | Real estate | 2018 |
| Asset London Properties Limited | Real estate | 2020 |
| Asset Management Services Limited | Real estate | 1992 |
| Assignment Consulting Limited | Professional & scientific | 2024 |
| Assist 24/7 Limited | Transport & logistics | 2017 |