| Approachable Parenting Community Interest Company | Education | 2011 |
| Approper Limited | Real estate | 2020 |
| Approved Brickwork and Repointing Ltd | Extraterritorial | 2024 |
| Approved Wills Ltd | Professional & scientific | 2022 |
| Appsage Ltd | Information & communication | 2024 |
| Appslynx Ltd | Information & communication | 2010 |
| Appt Ltd | Health & social care | 2025 |
| Appvertising Limited | Information & communication | 2019 |
| APQ Global Consultant Ltd | Professional & scientific | 2022 |
| APR Financial Consulting Limited | Professional & scientific | 2024 |
| Apra Development Ltd | Real estate | 2017 |
| Apra Homes Ltd | Real estate | 2017 |
| Apra Midlands Ltd | Real estate | 2021 |
| Apra Property Ltd | Real estate | 2017 |
| Apricot Consumer Technology Limited | Extraterritorial | 2012 |
| Apricot London Ltd | Health & social care | 2023 |
| Apricot RAM Limited | Real estate | 2011 |
| Apricus Group Limited | Health & social care | 2022 |
| Aprisa Ltd. | Transport & logistics | 2001 |
| APS Carpentry Midlands Limited | Manufacturing | 2021 |
| APS Corporate Trustee Limited | Professional & scientific | 2025 |
| APS International Limited | Financial services | 2009 |
| APS Metal Pressings Limited | Manufacturing | 1980 |
| APS Online Retails Ltd | Wholesale & retail | 2023 |
| APS Private Ltd | Transport & logistics | 2023 |
| APS4J Ltd | Professional & scientific | 2022 |
| Apsj Catering Limited | Hospitality | 2025 |
| Apsley Group Limited | Administrative & support | 2008 |
| Apstead Ltd | Professional & scientific | 2022 |
| APT 212 the Quadrant Sand Pits Birmingham B13RJ Ltd | Real estate | 2024 |
| APT Projects Limited | Professional & scientific | 2023 |
| APT Theatre Ltd. | Arts & recreation | 2026 |
| Apta Smith Limited | Real estate | 2017 |
| Aptagenix Oncology Ltd | Professional & scientific | 2026 |
| Aptcom Limited | Real estate | 2025 |
| APU Limited | Professional & scientific | 2008 |
| Apus Electrical Installations Ltd | Construction | 2017 |
| Apus Properties Ltd | Real estate | 2020 |
| APW Servicing Limited | Construction | 2016 |
| Apxil Limited | Wholesale & retail | 2024 |
| AQ Care Consultancy Ltd | Health & social care | 2025 |
| AQ Housing Accommodation Ltd | Hospitality | 2025 |
| AQ Opulent Estates Ltd | Construction | 2023 |
| AQ Portfolio Ltd | Real estate | 2025 |
| AQ Property Management Limited | Real estate | 2019 |
| Aqah Properties Limited | Financial services | 2017 |
| Aqeel & Brothers Property Holdings Ltd | Real estate | 2025 |
| AQG Limited | Hospitality | 2021 |
| AQG Security Service Ltd | Administrative & support | 2025 |
| AQI Properties Ltd | Real estate | 2024 |
| AQI Solutions Ltd | Information & communication | 2023 |
| Aqib Pharm Ltd | Health & social care | 2016 |
| Aqidah Limited | Hospitality | 2023 |
| Aqrawi Shawarma Ltd | Hospitality | 2025 |
| Aqsa Food Ltd | Hospitality | 2023 |
| Aqstar Ltd | Hospitality | 2021 |
| Aqteebabyproducts Ltd | Wholesale & retail | 2025 |
| Aqua Bliss Drinks Limited | Manufacturing | 2019 |
| Aqua Blue Clean Limited | Administrative & support | 2025 |
| Aqua Capital Investments Limited | Real estate | 2017 |
| Aqua Dive Adventures Limited | Education | 2025 |
| Aqua Entertainment UK Limited | Information & communication | 2018 |
| Aqua Green Heating & Plumbing Limited | Construction | 2009 |
| Aqua Plastering and Property Services Limited | Construction | 2025 |
| Aqua Spatial Limited | Professional & scientific | 2024 |
| Aqua Torque Solutions Limited | Construction | 2025 |
| Aqua Valley Ltd | Wholesale & retail | 2024 |
| Aqua WFP Window Cleaning Ltd | Construction | 2019 |
| Aquabit Limited | Administrative & support | 2004 |
| Aquafront Ltd | Professional & scientific | 2010 |
| Aquagen Energy Ltd | Manufacturing | 2023 |
| Aquagrey Health Ltd | Health & social care | 2022 |
| Aquahide Ltd | Wholesale & retail | 2020 |
| Aqualate Aggregates Limited | Mining & quarrying | 2015 |
| Aquaride Ltd | Wholesale & retail | 2024 |
| Aquarium Store Ltd | Wholesale & retail | 2020 |
| Aquarius Action Projects | Health & social care | 1989 |
| Aquarius BIO Limited | Wholesale & retail | 2021 |
| Aquarius Facilities Management Limited | Households | 2020 |
| Aquarius Group Limited | Administrative & support | 2019 |
| Aquarius Investments (Aston Lane) Ltd | Real estate | 2019 |
| Aquarius Investments Ltd | Real estate | 2017 |
| Aquarius Real Estate Management Limited | Administrative & support | 2018 |
| Aquasense AI Solutions Ltd | Water & waste | 2025 |
| Aquasense-Ai Ltd | Water & waste | 2025 |
| Aquasol Trading Ltd | Manufacturing | 2019 |
| Aquatech Installations Ltd | Energy | 2026 |
| Aquatech Midlands Ltd | Wholesale & retail | 2024 |
| Aquatell Solutions Limited | Real estate | 2017 |
| Aquavent Compliance Limited | Administrative & support | 2017 |
| Aquaz Events Limited | Wholesale & retail | 2024 |
| Aqube Ltd | Wholesale & retail | 2022 |
| Aquila Apartments & Management Ltd | Real estate | 2019 |
| Aquila Business Solutions Limited | Financial services | 2019 |
| Aquila Invest UK Ltd | Real estate | 2022 |
| Aquilon Tech Ltd | Information & communication | 2024 |
| Aquitania Accounting Limited | Professional & scientific | 2015 |
| Aqwa Sports Limited | Wholesale & retail | 2015 |
| AR & AV Ltd | Wholesale & retail | 2016 |
| AR 2 D World Ltd | Administrative & support | 2025 |