| Acuity Legal Limited | Professional & scientific | 2019 |
| Acuity Nominees Limited | Professional & scientific | 2000 |
| Acuity Project Solutions Limited | Professional & scientific | 2015 |
| Acuity Real Estate Advisers Limited | Professional & scientific | 2019 |
| Acuity Secretaries Limited | Professional & scientific | 2000 |
| Acuity Ventures LLP | | 2013 |
| Acumen Alliance Ltd | Wholesale & retail | 2023 |
| Acumen Capital Partners Ltd. | Information & communication | 2017 |
| Acumen Care Education Limited | Education | 2019 |
| Acumen Coaching Ltd | Other services | 2001 |
| Acumen Global Ltd. | Professional & scientific | 2015 |
| Acumen Trade Supplies Limited | Construction | 2018 |
| Acuntec Entertainment Limited | Information & communication | 2025 |
| Acute Recruit Consultants UK Ltd | Health & social care | 2019 |
| Acute Roofing Ltd | Construction | 2017 |
| Acute Training Solutions Limited | Education | 2008 |
| Acuti Ltd | Wholesale & retail | 2025 |
| Acvorn Limited | Wholesale & retail | 2024 |
| AD & Art Ltd | Wholesale & retail | 2024 |
| AD Astra ET Ultra LLP | | 2015 |
| AD Balance Solutions Limited | Professional & scientific | 2025 |
| AD Blitz Core Limited | Professional & scientific | 2025 |
| AD Construction Cardiff Ltd | Construction | 2026 |
| AD Dumont Ltd | Construction | 2019 |
| AD Hassan Limited | Wholesale & retail | 2025 |
| AD Hewitt Enterprises Limited | Health & social care | 2016 |
| AD HOC Collective Ltd | Professional & scientific | 2025 |
| AD HOC Designs Limited | Manufacturing | 2004 |
| AD Interact Ltd | Professional & scientific | 2008 |
| AD Precision Ltd | Manufacturing | 2015 |
| AD Spectra Works Limited | Professional & scientific | 2025 |
| AD UK Consultancy Group Limited | Health & social care | 2020 |
| AD Valorem Holdings Limited | Other services | 2015 |
| AD Wholesale Ltd | Wholesale & retail | 2025 |
| ADA Cavendish Group Ltd | Manufacturing | 2017 |
| ADA International Trading Ltd | Extraterritorial | 2016 |
| ADA Logistics Limited | Transport & logistics | 2019 |
| Adaigi Limited | Construction | 2020 |
| Adali ITH Ltd | Wholesale & retail | 2025 |
| Adalya Limited | Real estate | 2023 |
| Adam & EVE Enterprises Ltd | Health & social care | 2018 |
| Adam & Gemma Limited | Real estate | 2006 |
| Adam Hughes Wealth Management Ltd | Professional & scientific | 2018 |
| Adam Klanns International Company Ltd | Wholesale & retail | 2026 |
| Adam Lloyd Homes Ltd | Hospitality | 2018 |
| Adam Lloyd Ltd | Other services | 2018 |
| Adam Maintenance Ltd | Real estate | 2021 |
| Adam Martinez Autos Ltd | Wholesale & retail | 2024 |
| Adam Street Properties Limited | Construction | 2016 |
| Adam Wright Limited | Professional & scientific | 2014 |
| Adamas Studio Ltd | Wholesale & retail | 2009 |
| Adamfxcapitals Ltd | Financial services | 2021 |
| Adamo Gallery Limited | Wholesale & retail | 2021 |
| Adams & Hardcastle Ltd | Administrative & support | 2016 |
| Adams & Young Funeral Directors Ltd | Other services | 2022 |
| Adams Avenue Limited | Real estate | 2025 |
| Adams Bathrooms Ltd | Wholesale & retail | 2013 |
| Adams Courier Ltd | Transport & logistics | 2025 |
| Adams DS Properties Limited | Financial services | 2021 |
| Adana Restaurant Ltd | Hospitality | 2018 |
| Adapt Laboratories Ltd | Information & communication | 2025 |
| Adapt Leisure Limited | Arts & recreation | 2021 |
| Adaptdev Ltd | Information & communication | 2016 |
| Adaptech AI Ltd | Information & communication | 2022 |
| Adapthr Ltd | Administrative & support | 2024 |
| Adaptive Business Software Limited | Information & communication | 2012 |
| Adaptixpay Limited | Information & communication | 2025 |
| Adaptmyhome Limited | Extraterritorial | 2016 |
| Adasky Technologies Limited | Information & communication | 2022 |
| Adastanley and Family Ltd | Health & social care | 2022 |
| Adastra Cars Limited | Wholesale & retail | 2015 |
| Adastra International Ltd | Professional & scientific | 2017 |
| Adavak Ltd | Professional & scientific | 2021 |
| Adbow Ltd | Health & social care | 2016 |
| Adbus Ltd | Information & communication | 2025 |
| ADC Fire Systems Limited | Administrative & support | 2007 |
| Adco Holdings Ltd | Real estate | 2018 |
| Adco Property Ltd | Real estate | 2016 |
| ADD a Level Lofts Ltd | Construction | 2020 |
| ADD an Apron Ltd | Manufacturing | 2025 |
| ADD Group Construction Ltd | Construction | 2018 |
| Addaca Limited | Wholesale & retail | 2013 |
| Addapt Roofing and Building Contractors Ltd | Construction | 2012 |
| Adderley Featherstone Limited | Administrative & support | 1991 |
| Addex Innovation Technologies Ltd | Extraterritorial | 2020 |
| ADDINSERVICES18 Limited | Professional & scientific | 2018 |
| Addison Alfred Ltd | Information & communication | 2021 |
| Addition Global Ltd | Professional & scientific | 2023 |
| Addreax Group Limited | Financial services | 2019 |
| Addreax Solutions Limited | Financial services | 2019 |
| Addressed Limited | Professional & scientific | 2021 |
| ADE4CARE Limited | Administrative & support | 2023 |
| Adebite Limited | Health & social care | 2022 |
| Adec Property Limited | Real estate | 2022 |
| Adeel ADI Ltd | Wholesale & retail | 2025 |
| Adeel Hussain Limited | Wholesale & retail | 2025 |
| Adeel Traders Ltd | Wholesale & retail | 2025 |
| Adela Kiel Ltd | Manufacturing | 2026 |
| Adelin Services Limited | Construction | 2024 |
| Adell Bridges Yoga Ltd | Health & social care | 2019 |