| Alpine Experts Ltd | Education | 2023 |
| Alqasar Limited | Other services | 2022 |
| Alresford Garage Ltd | Wholesale & retail | 2023 |
| ALS Consult Limited | Professional & scientific | 2011 |
| Alsa Health Ltd | Transport & logistics | 2019 |
| Alsayd Ltd | Wholesale & retail | 2023 |
| Alston Asset Management Ltd | Manufacturing | 2018 |
| Alstons (Cabinets) Limited | Manufacturing | 1938 |
| Alstons (Upholstery) Limited | Manufacturing | 1951 |
| ALT Media Enterprise Ltd | Professional & scientific | 2022 |
| ALT UK Driver Training Limited | Education | 2015 |
| Altalaa Property Ltd | Real estate | 2021 |
| Altamont PUB Co Ltd | Hospitality | 2022 |
| Alternative Heating Solutions Limited | Wholesale & retail | 2020 |
| Alterreality Ltd. | Information & communication | 2017 |
| Altid Limited | Wholesale & retail | 2020 |
| Altitude Trampoline Club Ltd | Arts & recreation | 2025 |
| Altmarkt Services Ltd | Real estate | 2021 |
| Altura Place Management Company Limited | Households | 2019 |
| Aluma Services Ltd | Administrative & support | 2016 |
| Alvino Limited | Health & social care | 2019 |
| Alvis Suite Ltd | Wholesale & retail | 2025 |
| ALW Training Services Ltd | Education | 2012 |
| Always Warm Heating Ltd | Construction | 2018 |
| AM & S Solutions Ltd | Construction | 2024 |
| AM & YA Company Limited | Wholesale & retail | 2025 |
| AM GAS & Bathrooms Limited | Construction | 2025 |
| AM Regtech Ltd | Professional & scientific | 2019 |
| AM Wright Associates Ltd | Other services | 2012 |
| AM53 Ltd | Professional & scientific | 2025 |
| AMA Enterprises Limited | Real estate | 2002 |
| Amaams LLP | | 2012 |
| Amabilis Enterprises Limited | Professional & scientific | 2021 |
| Amalia Rowe Oral Health Ltd | Health & social care | 2025 |
| Amalyst Limited | Professional & scientific | 2012 |
| Amapola Homes Limited | Real estate | 2018 |
| Amar Corp Limited | Professional & scientific | 2017 |
| Amara Bridal Ltd | Wholesale & retail | 2017 |
| Amaris.Iliana Limited | Hospitality | 2023 |
| Amas Healthcare Limited | Wholesale & retail | 2019 |
| Amazeswim Ltd | Education | 2024 |
| Amazing Grace Care Limited | Health & social care | 2022 |
| Amazing Grace Hair and Beauty Salon Limited | Other services | 2020 |
| Amazing Grace Housing Limited | Real estate | 2024 |
| Amazing Houses Ltd | Real estate | 2021 |
| AMB Properties Portfolio Limited | Real estate | 2026 |
| Ambell Ltd | Financial services | 2024 |
| Ambella Limited | Professional & scientific | 2014 |
| Amber Landscape Consultant Services Limited | Administrative & support | 2023 |
| Amber Road Hotels Limited | Administrative & support | 1980 |
| Amber Road Travel Limited | Administrative & support | 1983 |
| Amberfield Developments Limited | Construction | 2014 |
| Amberfield Management Company Limited | Households | 2014 |
| Amberglass Presents Limited | Information & communication | 2016 |
| Amberley Homes Limited | Administrative & support | 2001 |
| Ambi RAY Ltd | Wholesale & retail | 2011 |
| AMC Electrical Group Limited | Construction | 2025 |
| Amco Sourcing Ltd | Other services | 2024 |
| AMD Service&Valeting Ltd | Wholesale & retail | 2022 |
| Amdel Ltd | Information & communication | 2025 |
| Ameera Talent Solutions Ltd | Administrative & support | 2025 |
| American Sweets Limited | Wholesale & retail | 2021 |
| Americover Limited | Financial services | 2013 |
| Amerio Forestry Contracts Ltd | Agriculture & fishing | 2023 |
| Amfah Healthcare Limited | Health & social care | 2023 |
| Amgps (Park Drive) Limited | Construction | 2016 |
| AMH Media Limited | Information & communication | 2025 |
| AMI Group Ltd | Wholesale & retail | 2025 |
| Amico Business Solutions Ltd | Wholesale & retail | 2025 |
| Amiee & Claires Blissful Creations Ltd | Arts & recreation | 2025 |
| Amigo Care Ltd | Health & social care | 2023 |
| Amis Healthcare Limited | Health & social care | 2023 |
| Amity Property Investments Ltd | Real estate | 2019 |
| Amjas Properties Ltd | Real estate | 2023 |
| Amlis & Associates Consulting Ltd | Professional & scientific | 2025 |
| Amlis Services Limited | Professional & scientific | 2018 |
| Ammwater Ltd | Households | 2007 |
| Amnesia Flowers Ltd | Wholesale & retail | 2022 |
| Amobox Ltd | Manufacturing | 2019 |
| Amodio LLP | | 2009 |
| Amore Beauty Lounge Ltd | Other services | 2023 |
| Amosp Solutions Ltd | Construction | 2026 |
| AMP Electrical (Essex) Ltd | Construction | 2007 |
| AMP Electrical Installations Ltd | Manufacturing | 2013 |
| AMP Retail Ltd | Wholesale & retail | 2019 |
| Ampaul Solutions Limited | Construction | 2013 |
| Amphora Commercial Holdings Ltd | Professional & scientific | 2017 |
| Amphora Services Ltd | Administrative & support | 2017 |
| Amphora Trading Ltd | Administrative & support | 2017 |
| Amplex Property Limited | Real estate | 2018 |
| Ampney Properties Limited | Households | 1994 |
| Amre Ltd | Real estate | 2024 |
| Amreen Ltd | Hospitality | 2023 |
| Amroth IT Consultancy Ltd | Information & communication | 2015 |
| AMS Business Consultants Limited | Professional & scientific | 2020 |
| Amsk Investments Ltd | Real estate | 2020 |
| AMY Gordon Ltd | Professional & scientific | 2020 |
| AN Inch OFF the MAP Ltd | Administrative & support | 2020 |
| An-Jhl Company Ltd | Real estate | 2021 |
| Analog Limited | Professional & scientific | 2018 |