| AA Construction & Carpentry Ltd | Construction | 2026 |
| AA TW Scaffolding Ltd | Construction | 2023 |
| AAA Fencing Services Limited | | 1985 |
| AAA Scientific Limited | Professional & scientific | 2014 |
| AAC Podiatry Ltd | Health & social care | 2026 |
| Aardvark Europe Limited | Professional & scientific | 2005 |
| Aardvark Juice Limited | Other services | 2015 |
| Aare Akande Limited | Health & social care | 2024 |
| Aart Diagnostics Ltd | Health & social care | 2020 |
| AAT Grounds Services Ltd | Agriculture & fishing | 2015 |
| Aayenda Limited | Information & communication | 2017 |
| AB Car Sales (South West) Ltd | Wholesale & retail | 2018 |
| AB Pest Solutions Limited | Administrative & support | 2025 |
| AB Property Services Limited | Construction | 2006 |
| AB Waste Removal Ltd | Water & waste | 2023 |
| AB5OLUTE Ltd | Wholesale & retail | 2024 |
| Abacus Blinds Limited | Manufacturing | 2006 |
| Abacus Building Design Limited | Professional & scientific | 1983 |
| Abacus Laundry Ltd | Other services | 2023 |
| Abacus Property Developments Limited | Construction | 2004 |
| Abax Group Ltd | Financial services | 2025 |
| Abbey Carpentry & Construction Ltd | Manufacturing | 2024 |
| Abbey Court Management Company (Tavistock) Limited | Households | 2008 |
| Abbey Grace Mole Ltd | Professional & scientific | 2023 |
| Abbey House Residents Association (Cirencester) Limited | Households | 1989 |
| Abbey Lift Trucks Limited | Manufacturing | 2021 |
| Abbeyfield Tamar Extra Care Society | Health & social care | 2019 |
| Abbott Building Solutions Ltd | Construction | 2024 |
| Abbott Utilities Limited | Construction | 2022 |
| ABC Medical & Research Associates Ltd | Health & social care | 2024 |
| ABC Plymouth Ltd | Hospitality | 2023 |
| ABC Warehouse Ltd | Transport & logistics | 2024 |
| ABC123 2023 Limited | Health & social care | 2023 |
| ABE Promotions Ltd | Arts & recreation | 2022 |
| Abel Health Solutions Ltd | Manufacturing | 2022 |
| Abercrombie 2000 Ltd | Households | 1998 |
| Abercrombie Safety Engineering Limited | Professional & scientific | 2002 |
| Abholly (2008) Limited | Health & social care | 2008 |
| Abigail Care Solutions Limited | Health & social care | 2025 |
| Able Drainage Limited | Water & waste | 1999 |
| Abled Motors South West Ltd | Transport & logistics | 2025 |
| Abmaritime Ltd | Construction | 2025 |
| ABN Media Ltd | Professional & scientific | 2021 |
| Abnick Limited | Professional & scientific | 2010 |
| Abode Property Management & Services Ltd | Real estate | 2023 |
| About Building Construction Ltd | Construction | 2025 |
| Above and Beyond Paint Specialists Limited | Construction | 2021 |
| Abrace C.I.C. | Health & social care | 2026 |
| Absolute Accommodation Plymouth LLP | | 2022 |
| Absolute Bubble Football Limited | Arts & recreation | 2022 |
| Absolute Legal Costs Limited | Professional & scientific | 2012 |
| Absolute Plumbing and Heating SW Ltd | Construction | 2024 |
| Absolute Product Design Limited | Professional & scientific | 2002 |
| ABZ Properties Ltd | Real estate | 2024 |
| AC Music and Events Limited | Information & communication | 2017 |
| AC Property Services Inc Ltd | Construction | 2012 |
| AC Rothwell Limited | Professional & scientific | 2023 |
| AC ST Ives Limited | Manufacturing | 2023 |
| Acanthis Insulation Limited | | 1986 |
| Acaster Estates Limited | Real estate | 2024 |
| ACC Language Services Ltd. | Professional & scientific | 2016 |
| Access Ecosse Limited | Mining & quarrying | 2017 |
| Access Plymouth Limited | Transport & logistics | 2011 |
| Accessmovers Limited | Transport & logistics | 2019 |
| Accessorise Depot Limited | Wholesale & retail | 2023 |
| Accomplished Plumbing & Bathrooms Limited | Construction | 2024 |
| Accountant Outsourcing Ltd | Professional & scientific | 2023 |
| Accountants South West Limited | Professional & scientific | 1997 |
| Ace Commodities Trading Limited | Extraterritorial | 2010 |
| Ace Double Glazing Ltd | Construction | 2013 |
| Ace Fencing Services (SW) Ltd | Administrative & support | 2023 |
| Ace Fire Alarms & Security Limited | Manufacturing | 1995 |
| Ace Fire Equipment (UK) Limited | Wholesale & retail | 1988 |
| Ace Fire Properties Limited | Construction | 2002 |
| Ace Installers Ltd | Manufacturing | 2010 |
| Ace Invest Limited | Hospitality | 2021 |
| Ace Mobility (SW) Ltd | Manufacturing | 2017 |
| Ace Plant Hire & Groundworks Services Ltd | Construction | 2016 |
| Ace Plastering SW Ltd | Construction | 2025 |
| Aceway Properties Limited | Real estate | 2021 |
| Acgroad Ltd | Construction | 2022 |
| ACH Rice UK Limited | Wholesale & retail | 2017 |
| Achievement Training Limited | Education | 1996 |
| Achievers Day Nursery Ltd | Health & social care | 2012 |
| Acklowe Ltd | Arts & recreation | 2023 |
| Acme (South West) Ltd | Professional & scientific | 2009 |
| Acorn Healthcare (SW) Ltd | Administrative & support | 2022 |
| Acquiro SW Limited | Construction | 2015 |
| Acre (SW) Ltd | Professional & scientific | 2012 |
| Acres Property Services Ltd | Real estate | 2025 |
| Acronyms Ltd | Information & communication | 2003 |
| Acryl Limited | Manufacturing | 2021 |
| ACS Custom SW Limited | Wholesale & retail | 2015 |
| ACS Electrical SW Ltd | Construction | 2020 |
| ACS Extreme Cleaning Limited | Administrative & support | 2025 |
| ACT Trading Activities Limited | Arts & recreation | 2023 |
| Actio Pro Ltd | Wholesale & retail | 2018 |
| Actionzz Limited | Information & communication | 2015 |
| Activ Design Ltd | Professional & scientific | 2025 |
| ACTIV8 IT Support Ltd | Information & communication | 2019 |