| Audiovestibular Consultancy Limited | Health & social care | 2023 |
| AUM Gemstone Group (AGG) Ltd | Wholesale & retail | 2025 |
| Aurea Talent Ltd | Administrative & support | 2025 |
| Auriella Limited | Wholesale & retail | 2021 |
| Auré Rituals Ltd | Manufacturing | 2025 |
| AUS Consultancy Limited | Other services | 2016 |
| Auto ENG Repair Ltd | Wholesale & retail | 2021 |
| Auto FIX Repair Ltd | Wholesale & retail | 2025 |
| Auto Land United Ltd | Professional & scientific | 2022 |
| Auto Moto Dealers Ltd | Wholesale & retail | 2023 |
| Auto Quick FIX Ltd | Wholesale & retail | 2019 |
| Auto Repair Palace Ltd | Wholesale & retail | 2020 |
| Auto Unique One Limited | Wholesale & retail | 2017 |
| Autocare Hub Ltd | Wholesale & retail | 2024 |
| Autofarhat Ltd | Wholesale & retail | 2023 |
| Autofly Car Services Ltd | Wholesale & retail | 2025 |
| AV Properties Ltd | Real estate | 2025 |
| AVA Estates Ltd | Real estate | 2021 |
| Avaks&Co Limited | Transport & logistics | 2019 |
| Avaloncrest Limited | Financial services | 1998 |
| Avalora Retail Ltd | Wholesale & retail | 2025 |
| Avancerad Limited | Real estate | 2014 |
| Avant-Garde Brands (London) Ltd | Manufacturing | 2019 |
| Avanti Optical Limited | Financial services | 2024 |
| AVC Compliance Ltd | Administrative & support | 2025 |
| Avenum Ltd | Wholesale & retail | 2019 |
| Avid Care Limited | Administrative & support | 2021 |
| Avid Pest Control Ltd | Water & waste | 2002 |
| Avon Ruby (UK) Limited | Construction | 1990 |
| Avoni Limited | Professional & scientific | 2013 |
| Avrora Project Ltd | Transport & logistics | 2010 |
| AVW Ltd | Real estate | 2025 |
| AW Business Birmingham Limited | Real estate | 2025 |
| AW Distributions Ltd | Wholesale & retail | 2023 |
| AWA Accounting Services Ltd | Professional & scientific | 2015 |
| AWA Fitness Limited | Wholesale & retail | 2022 |
| Awafi Foods Express Limited | Hospitality | 2026 |
| Awrsuk Ltd | Professional & scientific | 2025 |
| Axioma Solutions UK Limited | Information & communication | 2015 |
| Axsan Trading Ltd | Wholesale & retail | 2023 |
| AY Visualisation Ltd | Construction | 2022 |
| AYA Aesthetic London Ltd | Health & social care | 2025 |
| AYA Food Centre Ltd | Wholesale & retail | 2022 |
| Ayin Limited | Real estate | 2019 |
| Ayla Consultants Ltd | Education | 2018 |
| Ayla Estates Ltd | Real estate | 2026 |
| Ayla Roasted Nuts and Coffee Limited | Manufacturing | 2019 |
| Ayzt Consulting Ltd | Information & communication | 2022 |
| AZ Health Ltd | Health & social care | 2018 |
| AZC Ltd | Construction | 2009 |
| Azyx Ltd | Wholesale & retail | 2025 |
| B & C Ventilation Ltd | Manufacturing | 2025 |
| B & J Plumbing and Heating Supplies Limited | Wholesale & retail | 2001 |
| B & W Design Services(London)Limited | Real estate | 1971 |
| B and C Crestpearl Limited | Real estate | 2017 |
| B Create Limited | Arts & recreation | 2019 |
| B H & M G Gordon Consultants Limited | Professional & scientific | 2009 |
| B J S Company Limited | Manufacturing | 1945 |
| B Meti Ltd | Administrative & support | 2017 |
| B Solutions Limited | Wholesale & retail | 2021 |
| B W Chelmsford LLP | | 2004 |
| B.D. Haulage Limited | Construction | 2003 |
| B1LTON Food&Wine Ltd | Wholesale & retail | 2025 |
| Babalow Limited | Health & social care | 2020 |
| BABIES2PARENTS Ltd | Wholesale & retail | 2020 |
| Bacha Coffee UK Limited | Wholesale & retail | 2024 |
| Baddesley Accident & Hire Services Ltd | Financial services | 2013 |
| Badr Signs Ltd | Professional & scientific | 2020 |
| BAE Group Limited | Information & communication | 2026 |
| Bahanco Limited | Wholesale & retail | 2024 |
| Bain Consulting Limited | Professional & scientific | 2024 |
| Bajwa Maintenance Limited | Construction | 2025 |
| Bake Master Naseer Azizi Limited | Wholesale & retail | 2025 |
| Bake Station Limited | Administrative & support | 2014 |
| Baker Ibrahim Personal Training Ltd | Other services | 2015 |
| Bakery and Services LLP | | 2023 |
| Bala Catering Ltd | Hospitality | 2017 |
| Balady Bakery Ltd | Manufacturing | 2020 |
| Balance UP Ltd | Health & social care | 2015 |
| Baltej T Ltd | Wholesale & retail | 2024 |
| Bamboo Garden Landscaping Ltd | Hospitality | 2021 |
| Bamboo UK Nights Ltd | Hospitality | 2017 |
| Bamyan Arts Ltd | Professional & scientific | 2018 |
| Banadir Limited | Health & social care | 2020 |
| Banbridge Limited | Hospitality | 2023 |
| Banmary Ltd | Wholesale & retail | 2022 |
| Banyan House Ltd | Real estate | 2017 |
| Barakah London Ltd | Hospitality | 2025 |
| Barber Environmental (Nursery) Ltd | Agriculture & fishing | 2022 |
| Barber Environmental Ltd | Agriculture & fishing | 2013 |
| Barber for History Limited | Other services | 2023 |
| Barberian Ltd | Wholesale & retail | 2019 |
| Barbers Depot Ltd | Other services | 2016 |
| Barc Deals Ltd | Wholesale & retail | 2025 |
| Barlinco Properties Limited | Real estate | 2017 |
| Bart Construction Limited | Construction | 2012 |
| Bart House Ltd | Real estate | 2017 |
| Bartkowski Ltd | Construction | 2021 |
| Bartmanski Electrical Services Ltd | Construction | 2015 |
| Baruch Enterprises Limited | Wholesale & retail | 1992 |