| Abbey Field Construction Ltd | Construction | 2023 |
| Abbeyfield Oxford Society Limited(The) | Health & social care | 1959 |
| Abbeymagic Limited | Information & communication | 1990 |
| Abbott & Hunt Furniture Ltd | Manufacturing | 2016 |
| Abbotts Court (Oxford) Management Company Ltd | Households | 2022 |
| Abbybrooks Healthcare Ltd. | Administrative & support | 2021 |
| ABC Technologies Acquisitions Limited | Financial services | 2024 |
| Abchurch Holdings Limited | Real estate | 2026 |
| Abed & Co Ltd | Professional & scientific | 2013 |
| Aberclay (NI1) Limited | Financial services | 2021 |
| Aberclay (WS1) Limited | Financial services | 2020 |
| Aberclay (WS2) Limited | Financial services | 2020 |
| Aberclay Holdings Limited | Financial services | 2018 |
| Aberclay Limited | Professional & scientific | 2015 |
| Aberland World Service Ltd | Professional & scientific | 2024 |
| Abiden Limited | Hospitality | 2021 |
| Abiding Care and Support Limited | Hospitality | 2016 |
| Abiding Care Limited | Health & social care | 2016 |
| Abiding Care Services Limited | Health & social care | 2016 |
| Abiding Limited | Hospitality | 2016 |
| Abihope Care Solutions Ltd | Health & social care | 2013 |
| Abilene Christian University | | 2005 |
| Abingdon Accountancy Centre Limited | Professional & scientific | 2002 |
| Abingdon Bridge Marine Limited | Administrative & support | 2014 |
| Abingdon Designs Limited | Extraterritorial | 1992 |
| Abingdon IT Consultancy Ltd | Information & communication | 2003 |
| Abingdon Learning Trust | Education | 2012 |
| Abingdon Medical Limited | Health & social care | 2018 |
| Abingdon Riverfront Limited | Administrative & support | 2014 |
| Abingdon Rugby Football Club Ltd | Administrative & support | 2013 |
| Abingdon Secretaries Limited | Professional & scientific | 2002 |
| Abinglox Ltd | Real estate | 2025 |
| Abiotic Ltd | Professional & scientific | 2013 |
| Able Growing Centre Ltd | Professional & scientific | 2019 |
| Able Living Solutions Ltd | Construction | 2009 |
| ABM Lettings Ltd | Real estate | 2024 |
| Abnyservices Limited | Information & communication | 2024 |
| Absam Global Limited | Wholesale & retail | 2026 |
| Absencelink Ltd | Information & communication | 2025 |
| Absolute Zero Films Limited | Information & communication | 2012 |
| Abstract Leap Ltd | Information & communication | 2014 |
| Abulayla Kitchen Ltd | Hospitality | 2019 |
| Acacia & IVY Property Ltd | Real estate | 2025 |
| Academic Consulting Services Limited | Education | 2018 |
| Academic Union Oxford Limited | Education | 2017 |
| Accelerare Ltd | Professional & scientific | 2018 |
| Accelerating Expert Leaders Ltd | Administrative & support | 2018 |
| Acceleration Ltd | Information & communication | 2024 |
| Accelerox Limited | Extraterritorial | 2008 |
| Accellium Limited | Professional & scientific | 2020 |
| Access Developments Group Commercial Properties Ltd | Real estate | 2026 |
| Access Developments Group Ltd | Information & communication | 2017 |
| Access Developments Group Properties Ltd | Real estate | 2022 |
| Access Optic Ltd | Information & communication | 2022 |
| Accession Therapeutics Limited | Professional & scientific | 2020 |
| Accounting Advice Bureau Ltd | Professional & scientific | 2012 |
| Accountx Ltd | Professional & scientific | 2018 |
| Accubooks Consultancy Limited | Professional & scientific | 2025 |
| Accumen Management Limited | Administrative & support | 2011 |
| ACD Property Ltd | Real estate | 2024 |
| Ace Apparel Ltd | Wholesale & retail | 2022 |
| Ace Vision Euro Ltd | Extraterritorial | 2010 |
| Acequia Services Limited | Professional & scientific | 2021 |
| Acer Trust | Education | 2015 |
| Achi Afro Fitness CIC | Other services | 2025 |
| Ackacs Limited | Information & communication | 2014 |
| ACL Trading Ltd | Extraterritorial | 2019 |
| ACM Feilding Portfolio | Financial services | 2021 |
| ACM Staffing Ltd | Administrative & support | 2024 |
| Acnielsen (UK) Pension Plan Trust Limited | Financial services | 1997 |
| Acorn News Ltd | Wholesale & retail | 2018 |
| Acrown Services Ltd | Health & social care | 2019 |
| Acrs MOT & Repairs Ltd | Wholesale & retail | 2026 |
| Actikay Limited | Professional & scientific | 2016 |
| Activate Enterprise Limited | Education | 2014 |
| Activate Learning Investments Limited | Education | 2010 |
| Activave Ltd | Wholesale & retail | 2026 |
| Active Camps Limited | Arts & recreation | 2015 |
| Active Education & Training Limited | Arts & recreation | 2011 |
| Activequity Ltd | Professional & scientific | 2022 |
| Actual Illusions Ltd | Arts & recreation | 2023 |
| Aculife Limited | Health & social care | 2017 |
| Acumen Oxford Ltd | Professional & scientific | 2024 |
| Acuo AI Limited | Information & communication | 2025 |
| AD Heating Solutions Limited | Construction | 2020 |
| Ad&Sd Cleaning Limited | Administrative & support | 2023 |
| Adam Jones Medical Limited | Health & social care | 2010 |
| Adam Lettings Ltd | Real estate | 2025 |
| Adam Stacey Gardening Services Limited | Administrative & support | 2002 |
| Adam Sutton Limited | Arts & recreation | 2017 |
| Adamah Media CIC | Information & communication | 2024 |
| Adapt Initiative Limited | Professional & scientific | 2024 |
| Adaptix Limited | Professional & scientific | 2009 |
| Adda Talent Solutions Ltd | Administrative & support | 2024 |
| Added Health Limited | Health & social care | 2020 |
| Adder Analytics Limited | Information & communication | 2021 |
| Addy Marts Limited | Wholesale & retail | 2026 |
| Adedejico Limited | Mining & quarrying | 2022 |
| Adeolu Consults Limited | Administrative & support | 2023 |
| Adept Strategy Ltd | Wholesale & retail | 2012 |