| ASD Marketing Limited | Information & communication | 2019 |
| Asec Properties Limited | Administrative & support | 2019 |
| ASH House Nursery Limited | Education | 2002 |
| ASH Mountain Advisory Ltd | Information & communication | 2025 |
| ASH Structural Services Ltd | Professional & scientific | 2023 |
| Ashco Services Ltd | Construction | 2020 |
| Ashcroft Regulatory Solutions Limited | Professional & scientific | 2025 |
| Ashley Finishing Limited | Construction | 2024 |
| Ashmore Road Freeholder Limited | Households | 2026 |
| Ashton Faithfull Limited | Administrative & support | 2025 |
| Ashville Accountancy Limited | Professional & scientific | 2003 |
| Asian Super Dishes Limited | Hospitality | 2025 |
| Asimpson Coaching Ltd | Arts & recreation | 2024 |
| ASK Yvonne Ltd | Construction | 2020 |
| Ask-Bg Limited | Health & social care | 2017 |
| Ask-G Ltd | Education | 2016 |
| Ask-Gb Ltd | Health & social care | 2012 |
| Ask-Gb Properties Ltd | Real estate | 2021 |
| Asli Food Ltd | Hospitality | 2025 |
| Asma Grill Ltd | Hospitality | 2025 |
| Asoh Limited | Construction | 2017 |
| Aspect Estate Agents Limited | Real estate | 2009 |
| Aspect Security Solutions Ltd | Administrative & support | 2023 |
| Aspinalls Caravan Storage Limited | Transport & logistics | 2017 |
| Aspinalls Holdings Ltd | Real estate | 2017 |
| Aspire Accounting & Financial Management Ltd | Professional & scientific | 2013 |
| Aspire Rooms Official Ltd | Real estate | 2025 |
| Aspire Smile Clinic Ltd | Health & social care | 2025 |
| Aspire Smile Marketing Ltd | Professional & scientific | 2025 |
| Aspire Smile Studio Ltd | Health & social care | 2024 |
| Assembled Projects Ltd | Real estate | 2021 |
| Assess Social Care Consultancy Ltd | Health & social care | 2026 |
| Asset Condition Surveyors Limited | Professional & scientific | 2017 |
| Asset Valuations Limited | Administrative & support | 2023 |
| Assisi Pet Funeral Services Limited | Other services | 2013 |
| Assure Competence and Training Consultancy Limited | Administrative & support | 2022 |
| Aster CSE Ltd | Administrative & support | 2024 |
| Astra Marquees Ltd | Administrative & support | 2016 |
| Astranomad Ltd | Professional & scientific | 2024 |
| Astrum EQ Limited | Agriculture & fishing | 2025 |
| AT Heating Wirral Limited | Construction | 2019 |
| AT the Office Ltd | Real estate | 2017 |
| ATA Property Portfolio Ltd | Real estate | 2026 |
| Atay Fish Bar Ltd | Hospitality | 2022 |
| ATC Electrical Limited | Construction | 2013 |
| Ates Auto Parts Accessories HP Ltd | Manufacturing | 2021 |
| Atherton and Partners Limited | Construction | 1981 |
| Atlantic Partners US Ltd | Administrative & support | 2025 |
| Atlee Engineering Ltd | Construction | 2026 |
| Atna Limited | Real estate | 2015 |
| Atomicom Limited | Information & communication | 2010 |
| Audio Productions Limited | Information & communication | 2002 |
| Aughton Court Management Limited | Households | 1982 |
| Auntie Jayne's House Play Cafe Ltd | Hospitality | 2026 |
| Auracle Geospatial UK Limited | Administrative & support | 2022 |
| Auraven Ltd | Wholesale & retail | 2026 |
| Aureum Homes Ltd | Real estate | 2019 |
| Auroch Limited | Information & communication | 2026 |
| Authentic Approach Ltd | Professional & scientific | 2025 |
| Autism Together | Health & social care | 1991 |
| Auto Grow Life Limited | Wholesale & retail | 2018 |
| Auto Plant Glazing Limited | Wholesale & retail | 2011 |
| Autocraft North West Limited | Wholesale & retail | 2014 |
| Automait Ltd | Manufacturing | 2026 |
| Autotrade Solutions Limited | Wholesale & retail | 2003 |
| Autus HR Limited | Professional & scientific | 2005 |
| Auwin Competitions Ltd | Other services | 2023 |
| Auxilium Recruitment Ltd | Administrative & support | 2002 |
| Avaia Limited | Health & social care | 2022 |
| Availo-Trade Ltd | Information & communication | 2026 |
| Avalon School Educational Trust | Education | 2000 |
| Avant - Garde Products Limited | Construction | 2018 |
| Avantage Aesthetics Ltd | Health & social care | 2020 |
| Avaran Properties Limited | Real estate | 2023 |
| Aveb Ltd | Financial services | 2024 |
| Aventica Limited | Professional & scientific | 2004 |
| Avert Risk Ltd | Administrative & support | 2024 |
| Avial Ltd | Manufacturing | 2023 |
| Aviary Bridge Records Ltd | Information & communication | 2018 |
| Aviation Advice Ltd | Administrative & support | 2022 |
| Avida Education Ltd | Education | 2025 |
| Avidity IP Holdings Ltd | Financial services | 2006 |
| Avidity IP Ltd | Professional & scientific | 2006 |
| Avidity Media Group Limited | Financial services | 2025 |
| Avidity Studios Limited | Arts & recreation | 2023 |
| Avondale Civil Engineering Ltd | Administrative & support | 2021 |
| Avos Deals Global Ltd | Information & communication | 2019 |
| Avrora Group Ltd | Administrative & support | 2025 |
| AVT Retail Stores Ltd | Administrative & support | 2016 |
| Avtai Ltd | Extraterritorial | 2025 |
| AW Arts LLP | | 2024 |
| AWF Windows and Doors Limited | Manufacturing | 2024 |
| AWS Photography and Events Limited | Hospitality | 2022 |
| Axholme Property Management Limited | Households | 2019 |
| Axiom Building Limited | Construction | 2018 |
| Axis Construction Consultancy Limited | Construction | 2009 |
| Axis Surveying Limited | Professional & scientific | 2025 |
| Ayoub International Limited | Information & communication | 2019 |
| AZ Futures Ltd | Information & communication | 2019 |
| Aztec Sets Ltd | Arts & recreation | 2021 |