| Apricity Marketing Ltd | Professional & scientific | 2023 |
| Aqua Academy GB Ltd | Arts & recreation | 2005 |
| Aqua Vitae Ltd | Construction | 2025 |
| Aquafix 24/7 Ltd | Construction | 2025 |
| Aquaheat 4 U Ltd | Construction | 2025 |
| Aque Construction Ltd | Construction | 2024 |
| Aquilo Design LLP | | 2024 |
| AR Commercial Finance Limited | Financial services | 2016 |
| AR Instrumed UK Ltd | Manufacturing | 2025 |
| Ar's Collection Ltd | Information & communication | 2012 |
| AREPA2GO Limited | Hospitality | 2015 |
| Arff Sales Ltd | Information & communication | 2024 |
| Arka Foods Ltd | Wholesale & retail | 2024 |
| Arka House Ltd | Hospitality | 2024 |
| Arlete Composite Solutions Ltd. | Manufacturing | 2011 |
| Armsad Ltd | Health & social care | 2022 |
| Arnold Smith Consulting Limited | Professional & scientific | 2018 |
| Art Advisory Associates Limited | Administrative & support | 2001 |
| Art Design Ltd | Construction | 2026 |
| Art Four Ltd | Wholesale & retail | 2023 |
| Art-Vld Ltd | Wholesale & retail | 2018 |
| Artemis Associates Consultancy Ltd | Professional & scientific | 2019 |
| Artemis Static Services Limited | Professional & scientific | 2023 |
| Artemis Support Solutions Ltd | Administrative & support | 2015 |
| Articulate Sage Limited | Professional & scientific | 2020 |
| Artifex Carpentry Services Ltd | Manufacturing | 2020 |
| Artypotz Ceramics Limited | Arts & recreation | 2013 |
| AS Puzella Limited | Professional & scientific | 2017 |
| ASA Real-Estate Ltd | Real estate | 2019 |
| ASC Design Services Ltd | Professional & scientific | 2015 |
| Ascenddraft Ltd | Information & communication | 2026 |
| Ascott House RTM Company Limited | Households | 2022 |
| ASD Properties & Holdings Ltd | Real estate | 2026 |
| ASF IT Consulting Limited | Information & communication | 2009 |
| Ashbrae Estates Limited | Extraterritorial | 2025 |
| Ashby's Celebration Ltd | Hospitality | 2023 |
| Ashby's Wellbeing & Spa Ltd | Other services | 2023 |
| Ashford Plumbing & Heating Supplies Limited | Wholesale & retail | 2004 |
| Askham Holdings Limited | Real estate | 1988 |
| Aspenhill Care Ltd | Health & social care | 2023 |
| Aspire Bookkeeping Ltd | Professional & scientific | 2012 |
| Asrc Ltd | Real estate | 2023 |
| Assana Accounting Services Limited | Extraterritorial | 2023 |
| Assure Accountants Ltd | Professional & scientific | 2020 |
| Aston Apartments Limited | Households | 2003 |
| Astute Commercial Consultancy Ltd. | Information & communication | 2012 |
| Astute Commercial Consultants (UK) Ltd | Information & communication | 2018 |
| AT Building Construction Ltd | Construction | 2025 |
| AT Pace Mortgages Limited | Financial services | 2018 |
| AT Your Place Dining Ltd | Hospitality | 2025 |
| Athena Management Ltd | Real estate | 2019 |
| Athoria Ltd | Arts & recreation | 2023 |
| Atlantic Ship Design Ltd | Professional & scientific | 2021 |
| Atlantis Properties (Southern) Ltd | Hospitality | 2020 |
| Atwal-Ormiston Ltd | Real estate | 2024 |
| Auckland Freehold Limited | Households | 2008 |
| August Grey Enterprises Ltd | Real estate | 2024 |
| Aura Co Sports Ltd | Wholesale & retail | 2025 |
| Aura Productions Ltd | Information & communication | 2019 |
| Aurelo Web Studio Ltd | Information & communication | 2025 |
| Aurora Southsea Ltd | Hospitality | 2015 |
| Auto Speedy Garage Ltd | Wholesale & retail | 2024 |
| Autumn Gate Management Company Ltd | Households | 2021 |
| Auxilium Business Services Limited | Professional & scientific | 2018 |
| Auxilium Property Services Limited | Real estate | 2020 |
| AV Plumbing and Heating Ltd | Construction | 2018 |
| Awais Global Venture Ltd | Wholesale & retail | 2026 |
| Award Building Solutions Limited | Construction | 2016 |
| Awgeo Ltd | Professional & scientific | 2023 |
| AX Studio Limited | Information & communication | 2018 |
| Axton Investments Ltd | Real estate | 2025 |
| Ayla Afridi Ltd | Wholesale & retail | 2025 |
| AZ Spice Limited | Hospitality | 2020 |
| B & B Environmental Ltd | Water & waste | 2026 |
| B & J Car Sales Limited | Wholesale & retail | 2023 |
| B M O'Riordan Construction Ltd | Construction | 2026 |
| B&S Professional Services Ltd | Professional & scientific | 2018 |
| B2 Premium Limited | Wholesale & retail | 2014 |
| BA Drive UK Ltd | Transport & logistics | 2025 |
| BAA Healthcare Ltd | Health & social care | 2024 |
| Babagoni Ltd | Wholesale & retail | 2025 |
| Babybets Ltd | Arts & recreation | 2026 |
| Bahmanzad Ltd | Professional & scientific | 2026 |
| Baileys Fish and Chips Emsworth Limited | Hospitality | 2021 |
| Baja Pacifico Ltd | Hospitality | 2025 |
| Baked by Sweet Tooth Ltd | Wholesale & retail | 2025 |
| Bakes Construction Ltd | Construction | 2026 |
| Bakijo Limited | Administrative & support | 2015 |
| Balcarres Mansions Management Limited | Professional & scientific | 2002 |
| Balmoral Court Residents Company (Southsea) Limited | Households | 1987 |
| Bampton Health Care Limited | Wholesale & retail | 1996 |
| Bangash Polo Team Ltd | Arts & recreation | 2024 |
| Banjotait Limited | Arts & recreation | 2023 |
| Bar 54 Limited | Hospitality | 2019 |
| Barakah 786 Limited | Real estate | 2024 |
| Barakah Auto Garage Ltd | Wholesale & retail | 2016 |
| Barbertime Portsmouth Ltd | Other services | 2025 |
| Barbs Samrose Limited | Health & social care | 2022 |
| Bardington Apartments Limited | Real estate | 2024 |
| Bardington Management Limited | Real estate | 2026 |