| ANKOLET2 Ltd | Real estate | 2023 |
| Anlin Limited | Wholesale & retail | 1989 |
| Anna Sinclair Ltd | Extraterritorial | 2024 |
| Anne Johnson Ltd. | Information & communication | 2013 |
| Annshaws Living Ltd | Real estate | 2023 |
| Anomaly LDN Limited | Wholesale & retail | 2025 |
| Anotheranother Ltd | Manufacturing | 2025 |
| Anplas Ltd | Manufacturing | 2025 |
| ANS Accounts Ltd | Professional & scientific | 2022 |
| ANS Consults Limited | Information & communication | 2018 |
| ANS Global Ltd | Administrative & support | 2019 |
| Ansa Z Khan Limited | Other services | 2022 |
| Ansbro Properties Ltd | Real estate | 2026 |
| Anselm Court Management Company Limited | Households | 1999 |
| Answer 42 Ltd | Professional & scientific | 2023 |
| ANT Antiques Limited | Extraterritorial | 2016 |
| ANT Components Limited | Administrative & support | 2004 |
| ANT Group Limited | Administrative & support | 1994 |
| ANT Travel Limited | Transport & logistics | 2023 |
| Anthony Mills Ltd | Professional & scientific | 2014 |
| Anthony Saint Ltd | Hospitality | 2025 |
| Anthony Sanford Ltd | Manufacturing | 2016 |
| Anthony Shepherd Creative Ltd | Arts & recreation | 2023 |
| Anthus Consulting Limited | Information & communication | 2024 |
| Antico Holdings Ltd | Financial services | 2025 |
| Antigravity Ltd | Professional & scientific | 2021 |
| Antistat Limited | Wholesale & retail | 2004 |
| Antler Chew Wholesale Limited | Wholesale & retail | 2021 |
| Antley Holdings Ltd | Real estate | 2024 |
| Antoniab Ltd | Health & social care | 2019 |
| Anuradha Properties Ltd | Real estate | 2019 |
| Anvenna Group Limited | Financial services | 2025 |
| Anwara Enterprise Ltd | Hospitality | 2024 |
| ANY Three Words Ltd | Arts & recreation | 2023 |
| Anya Kilsha Limited | Information & communication | 2020 |
| Anyi Accomodation Services Ltd | Real estate | 2021 |
| Anyi Property Ltd | Real estate | 2021 |
| Anything & Everything International Limited | Wholesale & retail | 2020 |
| Anything and More Ltd | Wholesale & retail | 2024 |
| Anytime Health Ltd | Professional & scientific | 2021 |
| Anyzest Limited | Information & communication | 2025 |
| AOC Resins UK Ltd | Manufacturing | 2000 |
| AOK Consultancy Ltd | Professional & scientific | 2025 |
| AOR Albion Ltd | Water & waste | 2025 |
| AOR Media Ltd | Information & communication | 2022 |
| Aoto SEO Limited | Information & communication | 2025 |
| AP SD Sixteen Limited | Wholesale & retail | 2025 |
| AP SD Thirty Nine Limited | Wholesale & retail | 2025 |
| AP Tradelink Ltd | Wholesale & retail | 2020 |
| Apax Limited | Professional & scientific | 2021 |
| Apenee Property Limited | Real estate | 2022 |
| Aperitio Ltd | Professional & scientific | 2024 |
| Aperture Management Ltd | Professional & scientific | 2021 |
| Apex !T Consultancy Limited | Administrative & support | 2026 |
| Apex Advanced Courier Limited | Transport & logistics | 2025 |
| Apex Auto Services Ltd | Professional & scientific | 2025 |
| Apex Care Management Ltd | Health & social care | 2025 |
| Apex Commercial Recovery Ltd | Administrative & support | 2026 |
| Apex Evolution Services Ltd | Information & communication | 2023 |
| Apex Express Drivers UK Ltd | Wholesale & retail | 2025 |
| Apex Hifi Limited | Manufacturing | 2025 |
| Apex Medical Consultancy Ltd | Health & social care | 2024 |
| Apex Placement Limited | Hospitality | 2025 |
| Apex Property Build Ltd | Real estate | 2026 |
| Apex Property Projects Ltd | Construction | 2018 |
| Apexarc Ltd | Wholesale & retail | 2024 |
| Aphelion Anaesthesia Limited | Health & social care | 2025 |
| Aphrodite Treats Limited | Wholesale & retail | 2025 |
| Apiation Ltd | Information & communication | 2022 |
| Apogee Capital Management Ltd | Professional & scientific | 2025 |
| Apollo Anglian Ltd | Construction | 2018 |
| Apollo Farms Limited | Agriculture & fishing | 2002 |
| App a Ride Ltd | Transport & logistics | 2025 |
| App Dubs Limited | Information & communication | 2021 |
| Appfinder Ltd | Information & communication | 2025 |
| Apple Property Management Ltd | Real estate | 2024 |
| Applekitti Ltd | Information & communication | 2026 |
| APPLEKITTI2 Ltd | Professional & scientific | 2026 |
| Applet-It Limited | Other services | 2024 |
| Appletree Kitchens (UK) Limited | Construction | 2005 |
| Apprentx Ltd | Professional & scientific | 2026 |
| Approach Lifestyle Ltd | Education | 2022 |
| Apps Residence Limited | Information & communication | 2025 |
| Appsera Ltd | Wholesale & retail | 2025 |
| Appstract Studio Ltd | Information & communication | 2025 |
| Appstuners Limited | Information & communication | 2024 |
| Appsus Solutions Limited | Information & communication | 2025 |
| Apptilian Ltd | Information & communication | 2022 |
| Apptir Ltd | Wholesale & retail | 2024 |
| Apricus Financing Ltd | Wholesale & retail | 2021 |
| Aptitec Ltd | Information & communication | 2019 |
| Aptitude Property Group Ltd | Real estate | 2025 |
| Aptitude Recruits Ltd | Administrative & support | 2020 |
| Aptitude Stays Ltd | Real estate | 2026 |
| Aqneeq Ltd | Wholesale & retail | 2018 |
| Aqoptics Ltd | Health & social care | 2025 |
| Aqua Digital Rising Ltd | Information & communication | 2020 |
| Aqua Fauna UK Limited | Agriculture & fishing | 2024 |
| Aqua Ventures Ltd | Administrative & support | 2019 |
| Aquacrop(Uk)Crop Nutrition & Health Ltd | Manufacturing | 2026 |