| Ashton Construction Cirencester Limited | Extraterritorial | 1982 |
| Asia ZEN Willwriting Limited | Professional & scientific | 2018 |
| Asquith Consultancy Limited | Professional & scientific | 2013 |
| Assb Property Services Ltd | Real estate | 2024 |
| Associated Theatres Ltd | Arts & recreation | 2020 |
| Astrom Computing Limited | Information & communication | 1993 |
| ASW Ltd | Administrative & support | 2023 |
| Aswbuilding Ltd | Financial services | 2025 |
| Atba-Uk Limited | Arts & recreation | 2002 |
| Athaday Limited | Agriculture & fishing | 2001 |
| Athelstan Garages Limited | Real estate | 1965 |
| Athena Web Designs Ltd | Professional & scientific | 2011 |
| Atlantis Gems Limited | Wholesale & retail | 2013 |
| Auctus Global Limited | Professional & scientific | 2014 |
| Auctus Properties Ltd | Real estate | 2021 |
| Audacity Associates Ltd | Administrative & support | 2012 |
| Audit Angel Limited | Information & communication | 2023 |
| Aurelian Provenance Ltd | Hospitality | 2026 |
| Ausden Terrace (Swindon) Management Company Ltd | Real estate | 2018 |
| Autent Solutions Ltd | Professional & scientific | 2025 |
| Authentic Wood Floors Ltd | Manufacturing | 2023 |
| Autocare Legal Protection Ltd | Professional & scientific | 2005 |
| AVA and IVA Limited | Wholesale & retail | 2015 |
| Avantis Consulting Group Limited | Financial services | 2023 |
| Avantis Consulting Ltd | Professional & scientific | 2022 |
| Avantis Performance Ltd | Information & communication | 2023 |
| AVB Fabrications Ltd | Construction | 2024 |
| Avenue Coaching & Consultancy Limited | Professional & scientific | 2023 |
| Averystar Limited | Professional & scientific | 1995 |
| Aviation Info Tech Limited | Transport & logistics | 2022 |
| Avid Construction SW Ltd | Construction | 2025 |
| Avington Design Ltd | Professional & scientific | 2006 |
| Aviqi Limited | Health & social care | 2002 |
| Avis Adams Limited | Professional & scientific | 2023 |
| Avita Developments (Snargate) Ltd | Construction | 2021 |
| Avita Holdings Ltd | Real estate | 2026 |
| Avon Silk Mills Limited | Households | 1989 |
| AW Plumbing & Heating (Cotswold) Limited | Construction | 2011 |
| AW21 Investments Limited | Financial services | 2021 |
| AWB Management Limited | Manufacturing | 2015 |
| AWS Power Limited | Professional & scientific | 2011 |
| Axiom Communications Management Ltd | Professional & scientific | 2002 |
| Axis Dealer Ltd | Wholesale & retail | 2020 |
| Axis Management Consulting Limited | Professional & scientific | 1998 |
| Azur Marine Training Limited | Transport & logistics | 2006 |
| B a Trading | | 1992 |
| B M Prototyping Limited | Manufacturing | 2023 |
| B R Gardner Ltd. | Construction | 2003 |
| B.H.Cecil & Sons Limited | Information & communication | 1964 |
| B2 Design Limited | Professional & scientific | 1999 |
| Bable Consulting Limited | Professional & scientific | 2024 |
| Babygem Ltd | Hospitality | 2025 |
| Back on Track Sports Therapy Limited | Other services | 2025 |
| Bahn Stormers Limited | Wholesale & retail | 2006 |
| Baird Phillips Co. Ltd | Wholesale & retail | 2023 |
| Baitworks Limited | Wholesale & retail | 2014 |
| Baker & Co Practice Ltd | Health & social care | 2022 |
| Baker's Farm Leisure Limited | | 1982 |
| Ballymoore Limited | Wholesale & retail | 2020 |
| Bampton Valley Homes Limited | Real estate | 2025 |
| Banana Custard LLP | | 2022 |
| Banana Property Partners Ltd | Real estate | 2025 |
| BAR@LAKE6 Ltd | Hospitality | 2021 |
| Barbican Homes Ltd | Real estate | 2025 |
| Barley Energy Limited | Administrative & support | 2017 |
| Barn Anthology Ltd | Extraterritorial | 2019 |
| Barn SPV 1 Limited | Arts & recreation | 2023 |
| Barn SPV 2 Limited | Extraterritorial | 2023 |
| Barn SPV 3 Limited | Arts & recreation | 2023 |
| Barn Studio Partnership LLP | | 2006 |
| Barn Theatre Enterprises Limited | Information & communication | 2016 |
| Barnaby-Jesse Stephen Pearce Ltd | Extraterritorial | 2024 |
| Barrington Ayre Shirtmaker and Tailor Limited | Wholesale & retail | 2010 |
| Barsby Structural Consultants Ltd | Professional & scientific | 2020 |
| Bath Properties Limited | Real estate | 1997 |
| Bathurst Development Limited | Construction | 2013 |
| Bathurst Estate Farming Limited | Agriculture & fishing | 2019 |
| Bathurst Estate Holdings Limited | Real estate | 2013 |
| Bathurst Estate Leisure Limited | Hospitality | 2023 |
| Batten and Allen International Limited | Manufacturing | 1997 |
| Batten and Allen Limited | Manufacturing | 1972 |
| Batten Moore and Philpott Limited | Wholesale & retail | 2015 |
| Bavent Road Limited | Households | 2012 |
| Bays Management & Solutions Ltd | Construction | 2023 |
| Bays Property Ltd | Real estate | 2020 |
| BAZ and Fred Limited | Hospitality | 2012 |
| BBG Shipping Ltd | Transport & logistics | 2025 |
| BC Equine Veterinary Services Limited | Professional & scientific | 2022 |
| BC Performance Cars Ltd | Wholesale & retail | 2016 |
| Bcms Limited | Professional & scientific | 1997 |
| Beam Gymnastics | Arts & recreation | 2017 |
| Bearded Manatee Ltd | Professional & scientific | 2024 |
| Beauty by Clinta Ltd | Other services | 2022 |
| Becosoft Ltd | Information & communication | 2019 |
| Bedok Limited | Financial services | 2019 |
| Beehive Illustration Limited | Information & communication | 2009 |
| Beesly Consulting Ltd | Professional & scientific | 2012 |
| Belgravia Property Investments Limited | Real estate | 1998 |
| Belgravia Property Securities Limited | Real estate | 2006 |
| Bell & Kind Ltd | Administrative & support | 2026 |