| AKS COS Ltd | Hospitality | 2022 |
| Albany CP Limited | Real estate | 2024 |
| Albany DP Holdings Ltd | Financial services | 2024 |
| Albany House Services Limited | Real estate | 2009 |
| Albion Hill Properties Ltd | Households | 2012 |
| Albiroo Media Ltd. | Information & communication | 2026 |
| Aldersgate Arms Limited | Hospitality | 2024 |
| ALL Dolled UP Beauty Academy Ltd | Education | 2023 |
| ALL Event Solutions Limited | Hospitality | 2024 |
| ALL Figured OUT Bookkeeping Ltd | Professional & scientific | 2025 |
| ALL Grace African Market and Foods Ltd. | Wholesale & retail | 2023 |
| ALL Time High Ltd | Wholesale & retail | 2019 |
| Alliance Care and Support Limited | Health & social care | 2003 |
| Alliance Care Homes Limited | Health & social care | 2013 |
| Alloide Ltd | Manufacturing | 1996 |
| Allscapes & Fencing Ltd | Construction | 2016 |
| Allwin Access Scaffolding Limited | Construction | 2020 |
| Alph L & C Limited | Administrative & support | 2014 |
| Alpinium Limited | Other services | 2020 |
| Alresford Angling Association | Arts & recreation | 2023 |
| Alstrab Properties Ltd | Real estate | 2020 |
| Alternative Movement Ltd | Education | 2022 |
| Alymain Enterprises Limited | Manufacturing | 2024 |
| Amazing Activities Ltd | Education | 2015 |
| Ambrose, Went, Curtis Limited | Professional & scientific | 1991 |
| American Nails Clacton Ltd | Other services | 2026 |
| Amin Cottage Ltd | Hospitality | 2026 |
| Amira Cuisine Limited | Hospitality | 2020 |
| AMP Building Solutions Ltd | Construction | 2017 |
| Amplify Finance Limited | Professional & scientific | 2021 |
| Ancora Care and Support Group Ltd. | Health & social care | 2020 |
| Andrew Stockmarr Ltd | Professional & scientific | 2017 |
| Angela Ward Consultancy Limited | Wholesale & retail | 2013 |
| Angelic Facials Ltd | Other services | 2026 |
| Angelika BW Ltd | Health & social care | 2013 |
| Angelos Fashion Limited | Wholesale & retail | 2025 |
| Angie's Breakfast & Burger Shack Ltd | Hospitality | 2024 |
| Anglefield Court Management Company Limited | Real estate | 2005 |
| Angleside Facilities Limited | Administrative & support | 2020 |
| Anglia Business Consultancy Limited | Professional & scientific | 2020 |
| Anglia Holland PUB & Clubs Ltd | Hospitality | 2014 |
| Anglia Legal Ltd | Administrative & support | 2013 |
| Anglia Sports & Schoolwear Limited | Wholesale & retail | 1992 |
| Anglia Welding Company Limited | Construction | 1989 |
| Anglian Contract Services Ltd | Transport & logistics | 2019 |
| Anglian Vehicle Linings Limited | Manufacturing | 2005 |
| Anglo African Cooperation Limited | Administrative & support | 2014 |
| Anglo African Trade and Investment Limited | Administrative & support | 2014 |
| Anish & Partner Limited | Hospitality | 2025 |
| Anneva Ltd | Hospitality | 2020 |
| Another Level Construction Ltd | Construction | 2003 |
| Another Level Contracts Limited | Construction | 2020 |
| Antonina Farmer Ltd | Real estate | 2024 |
| Anytime Consulting Limited | Information & communication | 2011 |
| Anytime Electrics Limited | Construction | 2021 |
| Apex Civil Engineering Consultants Limited | Construction | 2026 |
| Apex Helios Limited | Wholesale & retail | 2026 |
| Apex Motorworks & Restorations Ltd | Wholesale & retail | 2024 |
| Apex Roofing & Building Services Ltd | Construction | 2025 |
| Apex Roofing & Insulation Ltd | Construction | 2025 |
| Apex Roofing and Groundworks Ltd | Construction | 2025 |
| Apexion Fire & Security Limited | Administrative & support | 2026 |
| Applebys(Removals)Limited | Transport & logistics | 1947 |
| Appshott Homes Ltd | Real estate | 2018 |
| Aqua Environmental Services Ltd | Administrative & support | 2018 |
| Aquaheat (East Anglia) Ltd. | Construction | 2001 |
| Aquinas (School Attendance Provisions) Ltd. | Health & social care | 2015 |
| AR Sahami Ltd | Hospitality | 2016 |
| ARC Landscapes & Fencing Limited | Administrative & support | 2024 |
| ARC Logistics Solutions Ltd | Transport & logistics | 2023 |
| Archangel Healthcare Ltd | Administrative & support | 2014 |
| Architecture Way Ahead Limited | Professional & scientific | 2019 |
| Argents Autos Limited | Wholesale & retail | 2017 |
| Arigostel Limited | Hospitality | 2023 |
| Arjobex Holding UK Limited | Financial services | 2020 |
| Arjobex Polyart Limited | Manufacturing | 2019 |
| Aroojana Retails Ltd | Wholesale & retail | 2024 |
| Arrow Bathrooms & Kitchens Limited | Construction | 2014 |
| Artomotif Design Limited | Professional & scientific | 2022 |
| AS Brickwork Essex Limited | Construction | 2018 |
| Ascendant Energy Limited | Construction | 2024 |
| Ascent Care, Training and Supplies Ltd | Health & social care | 2019 |
| ASH Court (Dovercourt) Management Limited | Households | 1987 |
| Ashbreedy Management Ltd Limited | Households | 2025 |
| Ashington Renewables Ltd | Energy | 2024 |
| Ashington Rise Investments Ltd | Construction | 2024 |
| Ashley John Tappenden Consultants Ltd | Professional & scientific | 2020 |
| ASK 4 Self Storage Ltd | Transport & logistics | 2019 |
| Aspect Mechanical Services Ltd | Construction | 2006 |
| Aspects Property Development Ltd | Construction | 2020 |
| Aspire for More Ltd | Hospitality | 2026 |
| Asset Tech Solutions Limited | Information & communication | 2025 |
| Association of Clinical Psychologists U.K. C.I.C. | Other services | 2018 |
| Asti 2006 Limited | Other services | 2013 |
| Astora Homes Limited | Construction | 2025 |
| ASV Clacton DT Ltd | Hospitality | 2019 |
| Atlantic Family Holdings Ltd | Financial services | 2023 |
| Atlantic Limited | Administrative & support | 2009 |
| Atlantic Metal Fabrication Limited | Manufacturing | 2017 |
| Atlantic Spa Limited | Construction | 2015 |