| Acacia Facilities Management Ltd | Real estate | 2009 |
| Academy Conferences Ltd | Education | 2009 |
| Academy Ltd | Education | 2016 |
| Acai Glow Ltd | Hospitality | 2026 |
| Access Christian Mediation Ltd | Other services | 2021 |
| Access Performance Solutions Limited | Administrative & support | 2011 |
| Accumbus Ltd | Professional & scientific | 2017 |
| Accupierce Limited | Wholesale & retail | 2006 |
| Ace Group Property Developments Ltd | Construction | 2024 |
| Acertaxi Ltd | Transport & logistics | 2026 |
| ACJ Management Services Limited | Administrative & support | 2005 |
| ACN Investments Limited | Real estate | 2019 |
| Acorn Carpentry Contractors Limited | Information & communication | 2014 |
| Acorn Classics House Limited | Financial services | 1978 |
| Acorn Developments (SW) Limited | Construction | 2003 |
| Acorn Developments 2 (SW) Limited | Real estate | 2019 |
| Acorn Developments 3 (SW) Limited | Real estate | 2019 |
| Acorn Developments SW (Devon) Ltd | Real estate | 2019 |
| Acorn Fashion Uniform and Workwear Ltd | Wholesale & retail | 2020 |
| Acorn Holiday Lets (SW) Limited | Real estate | 2022 |
| Acorn Homes (SW) Limited | Real estate | 2012 |
| Acorn Innovation Build Ltd | Construction | 2023 |
| Acorn Land (SW) Limited | Construction | 2007 |
| Acorn Lettings and Management (SW) Ltd | Real estate | 2013 |
| Acorn Woodwork Limited | Construction | 2003 |
| Acre Enterprises Limited | Financial services | 2020 |
| ACS Southwest Limited | Wholesale & retail | 2012 |
| Actiontrack Performance Company Limited | Arts & recreation | 2001 |
| Activate Change Limited | Education | 2003 |
| Active Robots (Retail) Limited | Wholesale & retail | 2018 |
| Active South West Ltd | Arts & recreation | 2024 |
| Acton Rock Ltd | Financial services | 2024 |
| Acuity Forensics Limited | Professional & scientific | 2013 |
| AD HOC Investments Ltd | Real estate | 2024 |
| ADA Property Investments Ltd | Real estate | 2019 |
| Adam Pitts Chickens Limited | Agriculture & fishing | 2009 |
| Adam's WET Burgers Ltd | Hospitality | 2020 |
| Adams Building Contractors (Somerset) Limited | Construction | 2016 |
| Adams Burnett Corporate Property Advisors Limited | Real estate | 2024 |
| Adams Hospitality Ltd | Hospitality | 2023 |
| Adapt Tape Ltd | Wholesale & retail | 2020 |
| Adcombe Consulting Limited | Professional & scientific | 2022 |
| Adcombe Developments Limited | Construction | 2007 |
| Adede UK Ltd | Extraterritorial | 2015 |
| Adeptal Limited | Professional & scientific | 2010 |
| Adetexui Limited | Information & communication | 2023 |
| ADG Services Southwest Ltd | Wholesale & retail | 2023 |
| Adhoc Media Limited | Professional & scientific | 2003 |
| Adima Group Ltd | Public administration | 2003 |
| Adina Saiu Limited | Wholesale & retail | 2014 |
| ADK Limited | Information & communication | 2002 |
| Administratiekantoor Zegge LLP | | 2014 |
| Admirals Landing Limited | Hospitality | 2019 |
| Admiralty Holdings Limited | Professional & scientific | 2002 |
| Adonis Healthcare Ltd | Health & social care | 2023 |
| ADP Consulting Limited | Professional & scientific | 2023 |
| Adpubmanagement Ltd | Hospitality | 2022 |
| Adrian Morris & Partners | | 1999 |
| Adsborough Builders (Taunton) Limited | Construction | 2014 |
| ADT Investments Limited | Real estate | 2018 |
| Advanced Carpet Care Limited | Administrative & support | 2006 |
| Advanced German Auto Servicing and Storage Solutions Limited | Wholesale & retail | 2023 |
| Advanced Mini Piling Systems Limited | Construction | 2005 |
| Advanced Veterinary Solutions Limited | Professional & scientific | 2022 |
| Adventurous FOX Limited | Financial services | 2016 |
| AE Publications Ltd | Information & communication | 2021 |
| AEM Accountancy Limited | Professional & scientific | 2023 |
| AEM Business Ltd | Information & communication | 2019 |
| Aeria Homecare Ltd | Administrative & support | 2023 |
| Aerial Communications Limited | Wholesale & retail | 2005 |
| Aesthetic Accounting Solutions Ltd | Professional & scientific | 2024 |
| Aether Consulting Services Limited | Professional & scientific | 2017 |
| Aevum Medical Ltd | Health & social care | 2026 |
| AEW Estates Ltd | Real estate | 2024 |
| AEW Properties Limited | Real estate | 2015 |
| Afflong Properties Limited | Real estate | 2025 |
| Affordit Motors Ltd | Wholesale & retail | 2025 |
| Africa Carbon Ltd | Professional & scientific | 2022 |
| Afrodishiac Ltd | Hospitality | 2024 |
| AG Mechanical Services Ltd | Construction | 2013 |
| AG Wills & Estate Planning Ltd | Professional & scientific | 2024 |
| Ag-Row Consultants Limited | Wholesale & retail | 2010 |
| Ag-Tech Holdings Ltd | Financial services | 2024 |
| Agasthiya Consult Fintech (UK) Limited | Financial services | 2025 |
| AGE UK Somerset | Health & social care | 1992 |
| AGE UK Somerset Trading Ltd. | Extraterritorial | 1999 |
| Agent Two Ltd | Professional & scientific | 2026 |
| Agents and Properties (Taunton) Limited | Real estate | 1997 |
| AGG Planning Associates Limited | Professional & scientific | 2009 |
| Agile Energy Limited | Professional & scientific | 2013 |
| Agilis Project Management Ltd | Construction | 2018 |
| Agimdrazhi Ltd | Construction | 2025 |
| AGK Consultancy Ltd | Professional & scientific | 2016 |
| AGM Rentals Ltd | Real estate | 2025 |
| Agora Creative Ltd | Professional & scientific | 2026 |
| Agroteam Ltd | Wholesale & retail | 2019 |
| AH Test Designs Ltd | Manufacturing | 2009 |
| Ahada Group Ltd | Real estate | 2025 |
| AHS Revive Ltd | Health & social care | 2023 |
| AI Barber Ltd | Other services | 2025 |