| Astra Engineering Products Limited | Manufacturing | 1990 |
| Astwood Consulting Limited | Information & communication | 2010 |
| Astwood Developments Limited | Extraterritorial | 2011 |
| Astwood Equities Limited | Financial services | 2011 |
| Astwood Farm Barns Limited | Households | 1994 |
| Astwood Holdings Limited | Financial services | 2019 |
| ATC Dynamic Ltd | Professional & scientific | 2026 |
| Atcore Ltd | Health & social care | 2007 |
| Athena Outsource Limited | Administrative & support | 2018 |
| ATJ Associates Limited | Professional & scientific | 2015 |
| ATK Precision Engineering Hire Ltd | Professional & scientific | 2025 |
| ATK Precision Engineering Ltd | Professional & scientific | 2025 |
| Atkins Energy Consulting Limited | Professional & scientific | 2012 |
| Atlantic International Freight Services Ltd | Transport & logistics | 2008 |
| Atlas Buildings Works Limited | Administrative & support | 2025 |
| Atlas Counselling and Support CIC | Health & social care | 2021 |
| Atlm Ltd | Construction | 2023 |
| ATS Plastics Limited | Manufacturing | 2015 |
| Attwoods (Bromsgrove) Limited | Professional & scientific | 2017 |
| Audacious Creative Communications Limited | Arts & recreation | 2012 |
| Audacious Technologies Limited | Information & communication | 2016 |
| Audio - TEK Events Ltd | Hospitality | 2022 |
| Augmented Imagination Global Ltd | Information & communication | 2026 |
| Aurora Print and Design Limited | Manufacturing | 2015 |
| Austco Marketing & Service (UK) Limited | Manufacturing | 2000 |
| Austin Group Holdings Ltd | Financial services | 2016 |
| Austin Property Holdings Ltd | Real estate | 2023 |
| Austin Transport Ltd | Transport & logistics | 1998 |
| Austin Transport Services Ltd | Extraterritorial | 2025 |
| Auto Logistics Limited | Transport & logistics | 2023 |
| Autohaus by Davies Ltd | Wholesale & retail | 2025 |
| Autohorizons Ltd | Wholesale & retail | 2014 |
| Automotive Garage Equipment Limited | Manufacturing | 2004 |
| Autotradenews Ltd | Information & communication | 2014 |
| Auxil Media Ltd | Professional & scientific | 2017 |
| Avanti Electrical & Property Services Limited | Construction | 2011 |
| Avatu Limited | Information & communication | 1992 |
| Avidity Wealth Management Holdings Limited | Financial services | 2010 |
| Avidity Wealth Management Limited | Financial services | 2010 |
| Avonview Services Limited | Construction | 2019 |
| AW Automotive Solutions Limited | Wholesale & retail | 2023 |
| AW Wealth Ltd | Financial services | 2021 |
| Axelstone Holdings Ltd | Financial services | 2025 |
| AXI5 Ltd | Manufacturing | 2019 |
| AXM Plumbing Services Ltd | Construction | 2025 |
| AXS Sales Limited | Administrative & support | 2010 |
| Ayurveda Heart & Lung Care Ltd | Health & social care | 2017 |
| B Major Productions Ltd | Information & communication | 2025 |
| B Money Promotions Ltd | Arts & recreation | 2021 |
| B P Hims Building & Maintenance Limited | Construction | 2020 |
| B S C a Limited | Arts & recreation | 2010 |
| B T Smith Ltd | Hospitality | 2023 |
| B V Fasteners Limited | Wholesale & retail | 2002 |
| B&E Plastering Services Ltd | Construction | 2023 |
| B. Richards Tree Services Ltd | Agriculture & fishing | 2022 |
| B6 Digital Ltd | Information & communication | 2018 |
| B60 Trading LLP | | 2013 |
| B60 Training Solutions Limited | Professional & scientific | 2012 |
| B61 Office Rental Ltd | Real estate | 2017 |
| BA Certification Limited | Professional & scientific | 2020 |
| Baash Auto Detailing Ltd | Administrative & support | 2025 |
| Baatfarf & Sons Limited | Arts & recreation | 2022 |
| Babel Consulting Limited | Professional & scientific | 2004 |
| Babyfoot Productions UK Limited | Information & communication | 2012 |
| Back Office Partners Limited | Administrative & support | 2026 |
| Back to the Toolbox Limited | Wholesale & retail | 2015 |
| Backdoor Productions Limited | Information & communication | 2012 |
| Backline Logistic Support Services Limited | Transport & logistics | 2008 |
| Backline Logistics Limited | Transport & logistics | 2004 |
| Backoffice One Limited | Administrative & support | 2017 |
| BAD to the BUN Ltd | Hospitality | 2025 |
| Badger AV Limited | Administrative & support | 2019 |
| Badwolf Consulting Ltd | Information & communication | 2007 |
| Bahaus Design & Construction Limited | | 1988 |
| Baildon Land Limited | Construction | 2023 |
| Bailey Care Services Limited | Administrative & support | 2014 |
| Bailey Employment Services Limited | Administrative & support | 1993 |
| Bailey Holdings (UK) Limited | Professional & scientific | 2009 |
| Ball Knowledge Ltd | Information & communication | 2025 |
| Bamerde Ltd | Other services | 2017 |
| Bampton Storage Limited | Administrative & support | 2014 |
| Banham Holdings Limited | Real estate | 2023 |
| Banjimak Consulting Limited | Professional & scientific | 2013 |
| Banks Wealth Management Limited | Administrative & support | 2011 |
| Banner House Management Company Limited | Real estate | 2016 |
| Bansi Trading Limited | Extraterritorial | 2021 |
| Bantock Gardens Residents Association Limited | Households | 1964 |
| Barbourne Worcester Ltd | Construction | 2015 |
| Barcox Investments Ltd | Real estate | 2021 |
| Bard and Arrow Limited | Real estate | 2012 |
| Bare Knuckle Limited | Arts & recreation | 2020 |
| Bark Inn Homing Ltd | Other services | 2026 |
| Bark Inn Kennels Ltd | Other services | 2010 |
| Barker Moss Healthcare Recruitment Limited | Administrative & support | 2013 |
| Barley Grange Management Limited | Households | 2007 |
| Barnsley Marshall Limited | Professional & scientific | 2003 |
| Barnstormer Holdings | Arts & recreation | 2017 |
| Barnstormer Properties Limited | Real estate | 2013 |
| Barnt Green Healthcare Limited | Wholesale & retail | 2022 |
| Barons Court House Management Ltd | Households | 2000 |