| A.C. Wallbridge and Company Limited | Construction | 1978 |
| A.C.T. Property Holdings Ltd | Other services | 2016 |
| A.E.P. (Modular Construction) Limited | Construction | 1997 |
| A.E.P. (Steel Fabrications) Limited | Manufacturing | 1988 |
| A.J. Mullen Ltd | Construction | 2001 |
| A.J. Waters Salisbury Ltd | Wholesale & retail | 2002 |
| A.K.Accounting Services Ltd | Professional & scientific | 2007 |
| A.L.L. Surfacing Contractors Ltd | Construction | 2010 |
| A.S.A. Recreations Limited | Administrative & support | 2009 |
| A2Z Cloud Ltd | Information & communication | 2015 |
| AA Automation Ltd | Information & communication | 2023 |
| AA Taxi Salisbury Ltd | Transport & logistics | 2024 |
| Aabs Investments Ltd | Real estate | 2026 |
| Aanraden Associates Ltd | Administrative & support | 2005 |
| AAO Property Investments Ltd | Real estate | 2026 |
| Aardvark & Giraffe Ltd | Information & communication | 2018 |
| Aathiddan Ltd | Hospitality | 2025 |
| AB Initio Limited | Agriculture & fishing | 1997 |
| AB Power Ltd | Professional & scientific | 2019 |
| Abacus Repro Limited | Wholesale & retail | 2003 |
| Abbotswood Park Management Company Limited | Households | 2012 |
| Abbotts Meadow (Bishops Itchington) Management Company Limited | Households | 2015 |
| ABC Fire & Safety Ltd | Administrative & support | 2023 |
| ABC Networking Limited | Information & communication | 2002 |
| Abelia Landscapes Ltd | Administrative & support | 2018 |
| ABG Events Limited | Administrative & support | 2024 |
| Abicare Services Limited | Other services | 2005 |
| Abiclean Services Limited | Extraterritorial | 2009 |
| Abigroup Holdings Limited | Financial services | 2014 |
| Abilink Services Limited | Other services | 2009 |
| Able Hands Together C.I.C. | Health & social care | 2015 |
| Abnl Overseas Ltd | Education | 2015 |
| Above & Beyond Normal Ltd | Professional & scientific | 2014 |
| Above and Beyond Bookkeeping Limited | Professional & scientific | 2015 |
| Abra Millar Limited | Professional & scientific | 2016 |
| ABSOLUT5 Audio Limited | Wholesale & retail | 2015 |
| AC Models Limited | Wholesale & retail | 2026 |
| Ac&Ca Ltd | Hospitality | 2022 |
| Acabs LLP | | 2007 |
| Academics (Peterborough) Management Company Limited | Real estate | 2018 |
| Acanthus Auctions Ltd | Wholesale & retail | 2025 |
| Accessory Depot (Salisbury) Ltd | Wholesale & retail | 2011 |
| Accountancy Matters (South) Ltd | Professional & scientific | 2006 |
| Accu Consulting Limited | Professional & scientific | 2025 |
| Ace Hosting Limited | Information & communication | 2017 |
| Acechild Limited | Professional & scientific | 2000 |
| Acer Building Products Limited | Wholesale & retail | 2011 |
| Aces HI Limited | Hospitality | 2019 |
| ACG - UK Limited | Transport & logistics | 2007 |
| Ackland Enterprises Ltd. | Information & communication | 2015 |
| ACM Painting & Decorating Limited | Construction | 2013 |
| Acorn Analytics Limited | Information & communication | 2011 |
| Acorn Grove (Fishbourne) Management Company Limited | Households | 2016 |
| Acorn View (Hyndburn) Management Company Limited | Households | 2021 |
| Acquisition and Development Consultancy Limited | Real estate | 2018 |
| ACS Endoscopy Limited | Professional & scientific | 2021 |
| ACS Salisbury Ltd | Administrative & support | 2021 |
| Activate for Kids Limited | Manufacturing | 2015 |
| Active Group Global Ltd | Financial services | 2025 |
| Active School Organisation Ltd | Education | 2025 |
| Acton House RTM Company Limited | Households | 2010 |
| AD Safety Consultants Ltd | Professional & scientific | 2019 |
| ADA Photography and Advertising Ltd | Professional & scientific | 2020 |
| ADA Plumbing & Heating Ltd | Construction | 2026 |
| Adam COX Engineering Ltd | Construction | 2015 |
| Adam Sawyer Plastic Surgery Limited | Health & social care | 2018 |
| Adam Short Painting & Decorating Ltd | Construction | 2020 |
| Adam's Autos Salisbury Ltd | Wholesale & retail | 2021 |
| Addiction Therapy London Limited | Health & social care | 2018 |
| Addison House Residents Management Company Limited | Households | 2005 |
| Addison Turl Limited | Professional & scientific | 2011 |
| Adept Circuits Ltd. | Professional & scientific | 2011 |
| Adept Computer Support Limited | Information & communication | 1994 |
| ADF Financial Consulting Ltd | Financial services | 2014 |
| ADH Taping and Jointing Limited | Construction | 2013 |
| Adhd Assist Ltd | Professional & scientific | 2025 |
| ADI Paint Spraying Ltd | Construction | 2020 |
| Admire Bees Ltd | Agriculture & fishing | 2025 |
| Adore Nail&Spa Ltd | Other services | 2019 |
| Adore Nails & Beauty NO.2 Limited | Wholesale & retail | 2021 |
| Adorn (Salisbury) Ltd | Other services | 2016 |
| Adrian Jones Consultancy Limited | Professional & scientific | 2009 |
| Adrian Nicolle & Co. Limited | Professional & scientific | 1995 |
| ADS Surveys Limited | Professional & scientific | 2014 |
| ADW Creative Limited | Arts & recreation | 2014 |
| Adycara Ltd | Wholesale & retail | 2021 |
| AE Matheson Ltd | Administrative & support | 2006 |
| AE Precision Engineering Ltd | Manufacturing | 2016 |
| Aegis Security Support Ltd | Administrative & support | 2015 |
| Aegis South Coast Ltd | Administrative & support | 2023 |
| AEM Services Limited | Information & communication | 2004 |
| Aequis Holdings Limited | Financial services | 2025 |
| Aerial Conservation Monitoring Limited | Professional & scientific | 2025 |
| Aeroelvira Limited | Manufacturing | 2007 |
| Aeroglow INT Limited | Professional & scientific | 2014 |
| Aeroteq Consulting Limited | Professional & scientific | 2017 |
| Aethereus Events Ltd | Administrative & support | 2015 |
| AF Southern Limited | Wholesale & retail | 2013 |
| AF Ventures Limited | Professional & scientific | 2018 |
| AFC Corporate Advisors UK Ltd | Administrative & support | 2014 |