| Aristocracy Developments Limited | Construction | 2005 |
| Aristocracy Holdings Limited | Professional & scientific | 2008 |
| Arjz Limited | Health & social care | 2018 |
| Armadillo Security Ltd | Administrative & support | 2023 |
| Armafone Ltd | Information & communication | 2019 |
| Arman Grill Ltd | Hospitality | 2025 |
| Armco Key Security Limited | Manufacturing | 2012 |
| Armery Limited | Professional & scientific | 2025 |
| Armonie Ltd | Professional & scientific | 2019 |
| Armstrong Property Services (East Anglia) Ltd | Construction | 2010 |
| Arnalita Limited | Transport & logistics | 2021 |
| Arnold & Barnes Electrical Services Ltd | Construction | 2019 |
| Aroma Delights Limited | Hospitality | 2024 |
| Aroma Fusion Ltd | Hospitality | 2026 |
| Aromatic Answers Ltd | Manufacturing | 2018 |
| Aron Barbers Ltd | Other services | 2023 |
| Around Town @ Limited | Professional & scientific | 1999 |
| ARP Logistics Limited | Transport & logistics | 2023 |
| Arrentee Sports Management Limited | Arts & recreation | 2020 |
| Arro Valeting Service Ltd | Administrative & support | 2025 |
| Arrow Property Development Ltd | Construction | 2025 |
| Arrowmead Limited | Wholesale & retail | 2022 |
| Arrows Services Ltd | Administrative & support | 2020 |
| Art EAT Events C.I.C. | Arts & recreation | 2018 |
| Art on the Prom Ltd. | Arts & recreation | 2015 |
| Art School Press Limited | Wholesale & retail | 2026 |
| Artaero Limited | Manufacturing | 2024 |
| Artemis Premier Properties Ltd | Real estate | 2024 |
| Artemis Signage Concepts Limited | Construction | 2019 |
| Arth Wellness Ltd | Manufacturing | 2026 |
| Artificial Intelligence Research Ltd | Professional & scientific | 2017 |
| Artisan Savant Floristry Limited | Wholesale & retail | 2023 |
| Artistic Greenscape Limited | Wholesale & retail | 2023 |
| Artorimo Limited | Other services | 2025 |
| Artrex Ltd | Wholesale & retail | 2025 |
| Arturs Service Ltd | Transport & logistics | 2018 |
| Arun Handling Services Ltd | Transport & logistics | 2020 |
| Arytur Ltd | Transport & logistics | 2026 |
| ARZ Advisory Limited | Professional & scientific | 2025 |
| AS Construction (Suffolk) Ltd | Construction | 2024 |
| AS Estate Holdings Ltd | Real estate | 2018 |
| AS Property Consultants Limited | Construction | 2016 |
| AS UK Investment Properties Ltd | Real estate | 2025 |
| As-Essentials Limited | Wholesale & retail | 2014 |
| Asap Branding Ltd | Professional & scientific | 2018 |
| Asat Services Limited | Information & communication | 2019 |
| Asaurus REX Ltd | Extraterritorial | 2025 |
| Ascenda AI Ltd | Information & communication | 2025 |
| Ascenda Engineering Ltd | Construction | 2004 |
| Ascender Creative Limited | Professional & scientific | 2023 |
| Ascentus Group Ltd | Professional & scientific | 2023 |
| ASH Electrical ( Suffolk ) Limited | Construction | 2016 |
| ASH Wallace Consulting Ltd | Arts & recreation | 2017 |
| Ashaya Limited | Health & social care | 2022 |
| Ashbocking Joinery Limited | Manufacturing | 2000 |
| Ashbury Construction Services Ltd | Construction | 2003 |
| Ashbury Fisheries Ltd | Agriculture & fishing | 2019 |
| Ashbury Gardens (Ipswich) Management Limited | Real estate | 2003 |
| Ashcroft Aviation Limited | Transport & logistics | 2017 |
| Ashden Homes Ltd | Real estate | 2025 |
| Ashe Controls (Northern) Limited | Manufacturing | 1983 |
| Ashe Controls Limited | Manufacturing | 1974 |
| Ashe Converting Equipment Limited | Manufacturing | 2008 |
| Ashe Upholstery Limited | Other services | 2015 |
| Ashen Tavern Limited | Manufacturing | 2025 |
| Asher Properties Limited | Administrative & support | 2017 |
| Ashfield Inns Ltd | Hospitality | 2026 |
| Ashford Construction Group Ltd | Construction | 2026 |
| Ashford Wright Limited | Construction | 2016 |
| Ashleigh Nelson Ltd | Arts & recreation | 2013 |
| Ashmeera Limited | Information & communication | 2014 |
| Ashti Kitchen Ltd | Hospitality | 2025 |
| Ashton Carpentry & Joinery Ltd | Manufacturing | 2016 |
| Ashton Enterprise Ltd | Wholesale & retail | 2021 |
| Ashton Motorsport Consultancy Limited | Professional & scientific | 2017 |
| Ashview Ltd | Real estate | 2022 |
| Asian Container Line Limited | Transport & logistics | 1998 |
| ASK Store Ltd | Wholesale & retail | 2025 |
| Askfrankie Limited | Information & communication | 2018 |
| ASL Store Ltd | Arts & recreation | 2016 |
| Aslan Fresh Fish Ltd | Hospitality | 2025 |
| Aslan Property Services Ltd | Administrative & support | 2021 |
| ASM Driving Ltd | Transport & logistics | 2026 |
| Asma AZA Properties Ltd | Real estate | 2026 |
| ASN Security Ltd | Administrative & support | 2019 |
| ASP Trading Ltd | Real estate | 2021 |
| Aspect Glass Limited | Manufacturing | 2019 |
| Aspen Build (East Anglia) Limited | Construction | 2011 |
| Aspen Build Group (E.A.) Limited | Financial services | 2021 |
| Aspen Build Holdings (E.A.) Limited | Financial services | 2020 |
| Aspen Courier Solutions Ltd. | Transport & logistics | 2020 |
| Aspen Holdings (E.A.) Limited | Construction | 2020 |
| Aspen New Homes (Nedging TYE) Limited | Construction | 2020 |
| Aspen New Homes (Norton) Limited | Construction | 2020 |
| Aspen New Homes Limited | Real estate | 2002 |
| Aspen Park Estates Limited | Real estate | 2018 |
| Aspirano Ltd | Wholesale & retail | 2021 |
| Aspiration Energy Limited | Construction | 2022 |
| Aspiration Facades Limited | Construction | 2010 |
| Aspiration Group Holdings Limited | Financial services | 2021 |