| Ambika Bros Limited | Hospitality | 2018 |
| Ambleside Apartments RTM Management Company Limited | Households | 2013 |
| Ambrose and Ambrose Ltd | Professional & scientific | 2021 |
| AMC Consultancy Services Limited | Professional & scientific | 2016 |
| Amco Brighton Limited | Construction | 2005 |
| Amelia Romero Investments Ltd | Real estate | 2015 |
| Ameliorate Living Limited | Administrative & support | 2022 |
| Amen Brother Ltd | Administrative & support | 2014 |
| Amenuveve Limited | Health & social care | 2014 |
| American Education Co UK Ltd | Education | 2024 |
| American Ingiliz Culture Publishers UK Ltd | Education | 2020 |
| American Vintage Hub Ltd | Wholesale & retail | 2026 |
| Amex Distribution Ltd | Administrative & support | 2019 |
| AMF (Crescent RD) Ltd | Construction | 2017 |
| AMF (Whitehill) Limited | Construction | 2017 |
| AMF Consultancy Services Limited | Professional & scientific | 2021 |
| AMG Enterprise Ltd | Real estate | 2019 |
| Amga Limited | Professional & scientific | 2023 |
| Amherst Group Limited | Extraterritorial | 2018 |
| Amherst Leisure Limited | Hospitality | 2003 |
| AMI Ji's Limited | Hospitality | 2007 |
| Amie BLU Ltd | Arts & recreation | 2023 |
| Amigees Ltd | Households | 2019 |
| Amil First Limited | Construction | 2025 |
| Amin Solicitors Limited | Professional & scientific | 2024 |
| Amir 1960 Limited | Hospitality | 2024 |
| Amirii House Ltd | Administrative & support | 2020 |
| Amirsadeq Property Ltd | Real estate | 2026 |
| Amit Mehta Dental Limited | Health & social care | 2025 |
| Amity Foundation Ltd | Other services | 2019 |
| Amity Weddings Limited | Professional & scientific | 2023 |
| AML Cleaning Service Limited | Administrative & support | 2011 |
| Ammetis Ltd | Professional & scientific | 2017 |
| Ammonite Projects Limited | Construction | 2008 |
| Amos Achilles Art Limited | Wholesale & retail | 2021 |
| AMP Pilates Ltd | Other services | 2021 |
| Amp-Paul Electrics Limited | Construction | 2024 |
| Amped Signals Labs Ltd | Information & communication | 2025 |
| Ampersand Inns Ltd | Hospitality | 2020 |
| Ampk Labs Limited | Health & social care | 2024 |
| Ample Training Ltd | Professional & scientific | 2020 |
| Amplicon Electronics Ltd | Manufacturing | 2020 |
| Amplicon Group Holdings Ltd | Professional & scientific | 2022 |
| Amplicon Liveline Limited | Other services | 1973 |
| Amply Ltd | Real estate | 2018 |
| Amsl Kirk Ltd | Real estate | 2011 |
| Amtrack Consulting Ltd | Information & communication | 2014 |
| Amuse the Butcher Limited | Arts & recreation | 2017 |
| AMV Law Group Ltd | Extraterritorial | 2017 |
| AMV Law Limited | Professional & scientific | 2009 |
| Amvic U.K. Limited | Education | 1989 |
| Amwick Floors Ltd | Construction | 2009 |
| Amygdalae Design Limited | Wholesale & retail | 2019 |
| Amzbams.Co.Uk Ltd | Wholesale & retail | 2020 |
| Amzee Limited | Wholesale & retail | 2025 |
| AN I for Interiors Limited | Other services | 2016 |
| AN Impact Limited | Professional & scientific | 2021 |
| AN8 Systems Limited | Information & communication | 2014 |
| Anacardia Ltd | Information & communication | 2016 |
| Analysis and Consultation Ltd | Information & communication | 2013 |
| Anatolian Love Counseling Ltd | Education | 2019 |
| Ancass Ltd | Transport & logistics | 2017 |
| Anchor AI Ltd | Information & communication | 2025 |
| Ancient and Modern Jewellers Limited | Wholesale & retail | 2007 |
| AND Interiors Ltd | Professional & scientific | 2018 |
| Anderida Investment Management Ltd | Professional & scientific | 2019 |
| Anders Bayley Scott Ltd | Financial services | 2011 |
| Anders Travel Limited | Real estate | 1986 |
| Anderson Norton Design Limited | Professional & scientific | 1997 |
| Anderson-Ford Limited | Wholesale & retail | 2013 |
| Anderton Properties Limited | Real estate | 2016 |
| Andmer Holdings Ltd | Real estate | 2026 |
| Andres Barber Ltd | Other services | 2023 |
| Andrew Colin Investments Limited | Professional & scientific | 2013 |
| Andrew Graham-Dixon Limited | Other services | 2025 |
| Andrew Lloyd & Associates Limited | Professional & scientific | 1994 |
| Andvis Ltd | Construction | 2022 |
| Andwill UK Ltd | Information & communication | 2018 |
| Andy Blunden Ceramic Wall & Floor Tilers Ltd | Construction | 2003 |
| Andysweb Limited | Information & communication | 2015 |
| Anemo Software Limited | Information & communication | 2022 |
| ANF Property Maintenance & Structural Repairs Ltd | Construction | 2015 |
| Angel Academe Nominee Limited | Administrative & support | 2017 |
| Angel Fish Facilities Limited | Administrative & support | 2018 |
| Angel Productions Limited | Information & communication | 1992 |
| Angel Walkers Ltd | Other services | 2021 |
| Angela Cheung Limited | Professional & scientific | 2004 |
| Angelique Panagos Ltd | Health & social care | 2016 |
| Angelpro Limited | Information & communication | 2009 |
| Angelux Limited | Real estate | 2018 |
| Anglehill Limited | Real estate | 1975 |
| Anglers National Line Recycling Scheme (Anlrs) CIC | Other services | 2019 |
| Anglo Dutch Estates Limited | Extraterritorial | 2006 |
| Anglocaters LND Limited | Hospitality | 2025 |
| Angry Creative (UK) Limited | Information & communication | 2020 |
| Animaker Ltd | Professional & scientific | 2025 |
| Animal Health Coaching Limited | Professional & scientific | 2024 |
| Animal Protection Agency | Information & communication | 2004 |
| Animal Protection Agency Foundation | Education | 2007 |
| Animated Data Limited | Information & communication | 2013 |