| Automatic Transmission Solutions Limited | Wholesale & retail | 2019 |
| Automation and Security Ltd | Other services | 2007 |
| Automerc Limited | Wholesale & retail | 2016 |
| Automotive Capital Management Limited | Wholesale & retail | 2016 |
| Automotive SL Ltd | Manufacturing | 2021 |
| Autonetics AI Ltd | Information & communication | 2025 |
| Autonomous Devices Limited | Manufacturing | 2014 |
| Autonymy UK Ltd | Manufacturing | 2026 |
| Autopoint MK Ltd | Professional & scientific | 2025 |
| Autopride Valets Ltd | Wholesale & retail | 2024 |
| Autopumps UK Ltd | Wholesale & retail | 2007 |
| Autorally Ltd | Transport & logistics | 2012 |
| Autorix Ltd | Wholesale & retail | 2023 |
| Autostir Ltd | Other services | 2024 |
| Autotech Academy Limited | Transport & logistics | 2021 |
| Autotech Connect Limited | Information & communication | 2023 |
| Autotech Group Limited | Professional & scientific | 2021 |
| Autotech Mobile Limited | Wholesale & retail | 2025 |
| Autotech Recruit Limited | Information & communication | 2010 |
| Autotech Training Limited | Transport & logistics | 2021 |
| Autovantage Vehicle Trading Limited | Administrative & support | 2025 |
| Autowerx Sales Ltd | Wholesale & retail | 2024 |
| Autowerx Service Ltd | Manufacturing | 2013 |
| Autowraps & PPF Limited | Manufacturing | 2019 |
| Autoz Driving School Ltd | Education | 2017 |
| Autumn Park Associates Limited | Administrative & support | 2012 |
| Auvic Ltd | Wholesale & retail | 2022 |
| Auxilios Management Solution Ltd | Information & communication | 2024 |
| Auxtail Limited | Manufacturing | 2016 |
| AV Consulting Limited | Construction | 2015 |
| AV Networks Limited | Information & communication | 2021 |
| AVA (Against Violence and Abuse) | Information & communication | 2009 |
| Avaconsult Limited | Information & communication | 2015 |
| Avail Properties Ltd | Hospitality | 2021 |
| Available AV Ltd | Information & communication | 2022 |
| Avakak Songs Limited | Arts & recreation | 1998 |
| Avala Enterprises Limited | Wholesale & retail | 2025 |
| Avalon Metal Coatings Limited | Manufacturing | 2014 |
| Avalon Organics Ltd | Wholesale & retail | 2025 |
| Avamee Investments Ltd | Real estate | 2023 |
| Avana Consulting Ltd | Professional & scientific | 2014 |
| Avaneo Limited | Professional & scientific | 2024 |
| Avaniko UK Limited | Information & communication | 2021 |
| Avari Tech Limited | Information & communication | 2022 |
| Avduron Assets Ltd. | Real estate | 2017 |
| AVE Maria Religious Supplies Ltd | Wholesale & retail | 2023 |
| Avebury Housing Limited | Real estate | 2025 |
| Avec Management Services Limited | Real estate | 2023 |
| Aveh Convenience Store Limited | Wholesale & retail | 2024 |
| Avenir Digital Limited | Information & communication | 2005 |
| Avento Limited | Information & communication | 2024 |
| Aventra Systems Limited | Information & communication | 2010 |
| Avenue Plumbing and Heating (MK) Limited | Construction | 2026 |
| Avenueuk Ltd | Professional & scientific | 2018 |
| Averon Capital Ltd | Professional & scientific | 2026 |
| Avery Davis Ltd | Real estate | 2023 |
| Avhs 2022 Limited | Real estate | 2021 |
| Avhs Hire Limited | Administrative & support | 2003 |
| Avhs Limited | Administrative & support | 1996 |
| Aviasa Ltd | Health & social care | 2019 |
| Aviat Ltd | Manufacturing | 2016 |
| Aviation Music Limited | Other services | 1978 |
| AVIATION47 Ltd | Manufacturing | 2022 |
| Avicon Solutions Limited | Professional & scientific | 2009 |
| Avid Info Limited | Information & communication | 2021 |
| Avida Labs Limited | Manufacturing | 2015 |
| Aviotech Limited | Manufacturing | 2014 |
| Aviotech Rotary Limited | Manufacturing | 2022 |
| Avira Ltd | Administrative & support | 2020 |
| Aviraa Services Ltd | Professional & scientific | 2011 |
| Avis Group Ltd | Real estate | 2026 |
| Avla Supply Limited | Wholesale & retail | 2026 |
| Avmin Limited | Wholesale & retail | 2025 |
| AVN Express Ltd | Wholesale & retail | 2025 |
| Avnita Properties Ltd | Real estate | 2017 |
| AVO UK Limited | Manufacturing | 2001 |
| Avocado Infinity Solutions Limited | Information & communication | 2018 |
| Avon China Limited | Hospitality | 2019 |
| AVP Transport Ltd | Transport & logistics | 2018 |
| Avro Mechanical Services Limited | Manufacturing | 2026 |
| AVS Financial Services Limited | Financial services | 2018 |
| AVS MK Limited | Wholesale & retail | 2024 |
| AVS Plastering Ltd | Construction | 2023 |
| AVS Vascular Imaging Ltd | Health & social care | 2014 |
| Avtec Worldwide Limited | Administrative & support | 2016 |
| Avtel (UK) Limited | Other services | 2008 |
| AVV Consulting Ltd | Health & social care | 2023 |
| AW Change Consulting Ltd | Professional & scientific | 2008 |
| AW Collective Ltd | Wholesale & retail | 2024 |
| AW Diesel Services Limited | Wholesale & retail | 2008 |
| AWA Sports Ltd | Arts & recreation | 2023 |
| Awadas Property Investments Ltd | Real estate | 2026 |
| Awaiis Ltd | Wholesale & retail | 2024 |
| Awake to Know Africa Community Interest Company | Arts & recreation | 2009 |
| Awambeng Logistics Ltd | Transport & logistics | 2025 |
| Awan Blue World Limited | Information & communication | 2022 |
| Awan Financial Services Limited | Financial services | 2011 |
| Award 3D Limited | Professional & scientific | 2015 |
| Award Property Group Limited | Real estate | 2021 |
| Awin Consulting Limited | Professional & scientific | 2024 |