| 1-8 Chapel Lane Management Company Ltd | Other services | 2019 |
| 10-13 ST Annes Mews (Wantage) Limited | Households | 2022 |
| 1000 Months Limited | Professional & scientific | 2019 |
| 1000MORE Ltd | Wholesale & retail | 2025 |
| 158 Abingdon Road (Oxford) Management Company Limited | Households | 1989 |
| 20:20 SPM Limited | Information & communication | 2007 |
| 24 Church Road Brackley Management Company Limited | Households | 2008 |
| 2CHERRIES Ltd | Professional & scientific | 2006 |
| 2PROTECT Limited | Extraterritorial | 2013 |
| 415 Wealth Ltd | Financial services | 2025 |
| 442 Logistics Ltd | Transport & logistics | 2006 |
| 4PAWS Grooming Ltd | Administrative & support | 2026 |
| 4PP Solutions Limited | Professional & scientific | 2020 |
| 4WARD Shop Limited | Wholesale & retail | 2022 |
| 5 EYE JAY UK Limited | Real estate | 2015 |
| 50021 Owners Limited | Transport & logistics | 2017 |
| 50026 Restoration Group Limited | Professional & scientific | 1994 |
| A Brand Holdings Co Ltd | Financial services | 2012 |
| A Brand Properties Limited | Real estate | 2024 |
| A G Cruickshank & Sons Limited | Construction | 2002 |
| A Khan Optics Ltd | Health & social care | 2010 |
| A to Z Taxi Executive Services Ltd | Transport & logistics | 2022 |
| A. B. S. General Builders Limited | Construction | 2025 |
| A.K. Building Services (Abingdon) Ltd | Construction | 2023 |
| A.W Building Services Ltd | Construction | 2017 |
| AAA RGL Limited | Health & social care | 2023 |
| AAD Carpentry Limited | Manufacturing | 2023 |
| ABAM3D Limited | Professional & scientific | 2021 |
| Abaz UK Limited | Wholesale & retail | 2020 |
| Abbey Group Property Management LLP | | 2020 |
| Abbotspen Ltd | Wholesale & retail | 2002 |
| ABC Healthcare Limited | Wholesale & retail | 2005 |
| Abeco Windows Limited | Construction | 2026 |
| ABG Tiling & Home Improvements Limited | Construction | 2016 |
| Abingdon Eagles Foundation CIC | Education | 2021 |
| Abingdon Road Management Company Limited | Households | 2016 |
| Abingdon Taxis Limited | Transport & logistics | 2016 |
| About YOU Bridal Ltd | Wholesale & retail | 2022 |
| Above & Beyond Plumbing Services Ltd | Construction | 2012 |
| AC Collective Limited | Wholesale & retail | 2022 |
| Ace Accountants Ltd. | Professional & scientific | 2003 |
| Acorn (Rowstock) Management Company Limited | Households | 2010 |
| Active Future South Oxfordshire CIC | Education | 2023 |
| Acuitas Business Intelligence Limited | Information & communication | 2023 |
| AD Atelier Ltd | Administrative & support | 2025 |
| Adali Wantage Ltd | Hospitality | 2025 |
| Adams Family Care Ltd | Health & social care | 2025 |
| Adeaedei Limited | Wholesale & retail | 2025 |
| Adlu Consultancy Ltd | Professional & scientific | 2018 |
| Adopted Apparel Limited | Wholesale & retail | 2025 |
| Adtec Electrical Services Ltd | Construction | 2014 |
| Advanced Biosystems Ltd | Professional & scientific | 2022 |
| Advanced Car Wash Ltd | Wholesale & retail | 2018 |
| Advanced Cryogenic Materials Limited | Professional & scientific | 2009 |
| Advanced Photonics Technologies UK Limited | Wholesale & retail | 2002 |
| Advhq Limited | Arts & recreation | 2021 |
| Advicedo Ltd | Information & communication | 2016 |
| Advocate&Advance Ltd | Education | 2025 |
| Aegis IT Solutions Ltd | Information & communication | 2026 |
| Affiliate Sitelines Ltd | Information & communication | 2025 |
| Affinity Caring Limited | Health & social care | 2022 |
| Aggregate Intelligence Limited | Other services | 2020 |
| Agility With AI Limited | Information & communication | 2025 |
| Agriculture, Plastics & Environment UK Ltd | Water & waste | 2015 |
| AH Home Developments Ltd | Real estate | 2017 |
| Ailsa Jane Aesthetics Ltd | Other services | 2022 |
| Air Tightness Solutions Limited | Construction | 2012 |
| Airborne Engineering Limited | Manufacturing | 2001 |
| Airbox Aerospace Limited | Information & communication | 2016 |
| Airbox Data Services Limited | Information & communication | 2017 |
| Airbox Holdings Limited | Financial services | 2023 |
| Airbox Systems Limited | Wholesale & retail | 2008 |
| Aisling O'Keeffe Medical Writing Limited | Professional & scientific | 2016 |
| Aiva Holdings Limited | Financial services | 2023 |
| Aiva Limited | Agriculture & fishing | 2015 |
| AJB Cooling Ltd | Construction | 2025 |
| AJC Project Services Ltd | Construction | 2015 |
| AK Performance Tuning Limited | Wholesale & retail | 2021 |
| Akenhurst Consultants Ltd | Professional & scientific | 1999 |
| Akitorosa Limited | Information & communication | 2025 |
| Alan Bennett Biotechnology Consulting Ltd | Professional & scientific | 2022 |
| Alan Edward Gardeners Limited | Administrative & support | 2023 |
| Alana Homes Limited | Real estate | 2025 |
| Alani Medical Limited | Health & social care | 2020 |
| Aldena One Ltd | Professional & scientific | 2013 |
| Aldena Two Ltd | Professional & scientific | 2013 |
| Alder Consultancy Ltd | Professional & scientific | 2012 |
| Alder's Electrical Limited | Construction | 2023 |
| Alex Metcalfe DOP Limited | Information & communication | 2007 |
| Alikozai Ltd | Professional & scientific | 2025 |
| Alkaline Lake Ltd | Real estate | 2010 |
| Allaccesspadel Ltd | Arts & recreation | 2025 |
| Allen Relo Ltd | Transport & logistics | 2022 |
| Allister Godfrey Architects Ltd | Professional & scientific | 2010 |
| Aloe Home Care Ltd | Health & social care | 2026 |
| ALT Quality Consulting Limited | Professional & scientific | 2016 |
| AMA Pizza Wantage Limited | Hospitality | 2020 |
| Amamani Collective Ltd | Wholesale & retail | 2026 |
| Amanah Capital Holdings Limited | Real estate | 2026 |
| Amanda Harding Limited | Administrative & support | 2016 |