| Ambient Control Limited | Administrative & support | 2006 |
| Ambient Limited | Construction | 2015 |
| Ambiserv Renewables Ltd | Manufacturing | 2021 |
| Ambr-Pp Limited | Real estate | 2021 |
| Amdega Repairs Ltd | Manufacturing | 2023 |
| AME Associates Limited | Wholesale & retail | 2015 |
| AME Licensed Ltd | Transport & logistics | 2019 |
| American Nails DVN Ltd | Other services | 2018 |
| Amethyst Risk Management Limited | Professional & scientific | 2007 |
| Amex Developments Limited | Construction | 2005 |
| Amex Holdings Limited | Construction | 1990 |
| Amfs Services Ltd | Construction | 2026 |
| AMG Estates Limited | Construction | 2010 |
| AMG Property Finance Limited | Financial services | 2023 |
| AMH Organisation Limited | Professional & scientific | 2015 |
| Amira Group Ltd | Construction | 2018 |
| Amjak Ltd | Wholesale & retail | 2020 |
| AMK Sourcing Ltd | Manufacturing | 2025 |
| AML Electrical Ltd | Construction | 2023 |
| Ammh Limited | Real estate | 2025 |
| Amogh Limited | Construction | 2019 |
| Amoore's Beauty and Aesthetics Limited | Other services | 2022 |
| Amore Ristorante Italiano Ltd | Hospitality | 2019 |
| Ampereplus Electrics Limited | Construction | 2021 |
| Ampk Services Ltd | Wholesale & retail | 2026 |
| Amra Consultancy Limited | Information & communication | 1998 |
| AMS Charlton Ltd | Information & communication | 2025 |
| AMS Global Solutions Ltd | Information & communication | 2025 |
| AMS Mayfair Limited | Construction | 2005 |
| Amsom Limited | Professional & scientific | 2017 |
| AMT Homes Limited | Real estate | 2016 |
| AMT Productions Ltd | Information & communication | 2026 |
| AMY Bushell Psychology Ltd | Health & social care | 2024 |
| ANA Consulting Services Ltd | Professional & scientific | 2026 |
| Anaari Enterprises Limited | Wholesale & retail | 2020 |
| Anaari Limited | Wholesale & retail | 2015 |
| Anaishewenyasha Limited | Health & social care | 2018 |
| Anakay Limited | Information & communication | 2012 |
| Analika's Ltd | Wholesale & retail | 2025 |
| Analytica Consulting Ltd | Information & communication | 2019 |
| Analytical Approach Limited | Information & communication | 1998 |
| Analyttica Datalab Private Limited | Information & communication | 2023 |
| Anantya Consulting Ltd | Other services | 2025 |
| Ancestral Care Ltd | Health & social care | 2022 |
| Anchorwaters Limited | Professional & scientific | 2026 |
| Andac Properties Limited | Real estate | 2002 |
| Andiamo Holdings Limited | Wholesale & retail | 2019 |
| Andiamo International Limited | Wholesale & retail | 1991 |
| Andover Scaffolding Ltd | Construction | 2022 |
| Andrea's School of Motoring Ltd | Education | 2002 |
| Andrew Lord Training Ltd | Information & communication | 2014 |
| Andrew Robson Bridge Club Limited | Arts & recreation | 1995 |
| Andrew Robson Bridge Holidays (Millstream) Limited | Administrative & support | 2014 |
| Andrew Robson Bridge Holidays Limited | Administrative & support | 2014 |
| Andrew Robson Bridge Weekends Limited | Education | 2024 |
| Andrews & Wykeham Holdings Limited | Administrative & support | 2019 |
| Andrews & Wykeham Limited | Administrative & support | 2008 |
| Andrews Property Estates Limited | Construction | 2023 |
| Angela Martin Ltd | Professional & scientific | 2018 |
| Angelheath Limited | Construction | 1988 |
| Angello Concept Ltd | Construction | 2016 |
| Angels Business Services Limited | Administrative & support | 2010 |
| Angian Limited | Wholesale & retail | 2024 |
| Angian Property Limited | Real estate | 2026 |
| Anglis Rural Mobility Limited | Wholesale & retail | 2009 |
| Angliss Developments Ltd | Real estate | 2019 |
| Anglo River Enterprises (UK) Co. Ltd | Wholesale & retail | 2008 |
| Anina Property Limited | Real estate | 2024 |
| ANL Driving Logistic Ltd | Transport & logistics | 2025 |
| ANL Holm Ltd | Professional & scientific | 2015 |
| Anmd Square Ltd | Administrative & support | 2021 |
| Anmoll Ltd | Real estate | 2018 |
| Anna Survey Ltd | Professional & scientific | 2017 |
| Anne Janaway and Sons LLP | | 2001 |
| Annehu Ltd | Real estate | 2025 |
| Annitech Ltd | Information & communication | 2014 |
| Anson Holdings Ltd | Real estate | 2022 |
| Antava Luxy Living Ltd | Real estate | 2022 |
| Anthony a. Bull Limited | | 1979 |
| Antidote Services Ltd | Administrative & support | 2026 |
| Antonia Edwards Upholstery Limited | Other services | 2014 |
| Antronics Limited | Professional & scientific | 1998 |
| ANU Caterers Ltd | Hospitality | 2021 |
| Anushree Limited | Real estate | 2017 |
| Anushree Restaurants Ltd | Hospitality | 2018 |
| Anything Analytics Ltd | Professional & scientific | 2026 |
| AO & Associates Ltd | Administrative & support | 2016 |
| AOG MX Ltd | Manufacturing | 2018 |
| Aown Clothing Limited | Wholesale & retail | 2025 |
| AP Aviation Ltd | Professional & scientific | 2012 |
| AP Coaching Ltd | Education | 2021 |
| Apadministration Ltd | Public administration | 2025 |
| Apathetic Limited | Wholesale & retail | 2023 |
| Apertura Products Ltd | Construction | 2023 |
| Apex Lofts and Carpentry Limited | Construction | 2024 |
| Apex Secure Solutions Ltd | Construction | 2024 |
| Apex UK Ledgers Ltd | Professional & scientific | 2025 |
| Apex Universal Trading Ltd | Wholesale & retail | 2025 |
| Apey Consulting Ltd | Professional & scientific | 2025 |
| APG Executive Cars Ltd | Transport & logistics | 2021 |