| Additions Accountancy (Grantham) Ltd | Professional & scientific | 2013 |
| Adex Digital Solutions Ltd | Information & communication | 2023 |
| Adlg Limited | Agriculture & fishing | 2025 |
| Adpost Network Ltd | Information & communication | 2023 |
| Advance Property Developments (UK) Limited | Construction | 2008 |
| Advanced Child Safeguarding Services Limited | Health & social care | 2017 |
| Advanced Digital Research (UK) Ltd | Professional & scientific | 2017 |
| Advanced Paving Limited | Construction | 2018 |
| Advanced Property Services (East Midlands) Limited | Real estate | 2020 |
| Adversair Limited | Professional & scientific | 2022 |
| ADVOC8 Ltd | Professional & scientific | 2018 |
| AED Holdings Ltd | Households | 2025 |
| Africana Trading Ltd | Wholesale & retail | 2026 |
| AFS Contractors Limited | Agriculture & fishing | 2015 |
| AFS Dean Limited | Extraterritorial | 2021 |
| AG Printing Ltd | Manufacturing | 2025 |
| Agape Healthcare Consultancy Limited | Professional & scientific | 2026 |
| Agents Together 2.0 Limited | Other services | 2025 |
| Agincourt Consultancy Ltd | Information & communication | 2018 |
| Agri Smart Ltd | Agriculture & fishing | 2014 |
| Agrireach Ltd | Wholesale & retail | 2026 |
| AI Cloud Services Ltd | Information & communication | 2026 |
| AI Nexus Technologies Limited | Information & communication | 2024 |
| Aigburth Ltd | Hospitality | 2022 |
| Ainthorpe Ltd | Construction | 2022 |
| Air CON - 1 Ltd | Construction | 2024 |
| Airhearth Ltd | Wholesale & retail | 2024 |
| Airless Audio Ltd | Information & communication | 2026 |
| Aisby Developments Ltd | Construction | 2021 |
| Aitchenby Investments Limited | Real estate | 2017 |
| AJ Service Station Ltd | Wholesale & retail | 2021 |
| AJC Property Management Limited | Real estate | 2021 |
| AJD Coldstore Construction Limited | Construction | 2017 |
| Ajxa Ltd | Other services | 2015 |
| Akroteria Limited | Professional & scientific | 2022 |
| Alam and Khan Ltd | Real estate | 2021 |
| Alam Locums Ltd | Health & social care | 2012 |
| Alan Litman Limited | Wholesale & retail | 2007 |
| Alana's Aesthetics Academy Limited | Other services | 2023 |
| Alarif Developmets Ltd | Real estate | 2026 |
| ALC Properties Limited | Professional & scientific | 1998 |
| Alcsis LLP | | 2006 |
| Alecu I&A Ltd | Wholesale & retail | 2023 |
| Alevate Hydrate Ltd | Wholesale & retail | 2025 |
| Alewater Limited | Administrative & support | 2015 |
| Alexander Capital Limited | Financial services | 2024 |
| Alfonso Consulting Limited | Professional & scientific | 2015 |
| Alfras Investments Limited | Real estate | 2023 |
| ALI 2014 Ltd | Real estate | 2024 |
| ALI Shar Limited | Real estate | 2025 |
| Alice Margiotta Consultancy Ltd | Professional & scientific | 2023 |
| Align & Revive Limited | Health & social care | 2024 |
| Alish Grantham Limited | Real estate | 2020 |
| Alive Collective Limited | Professional & scientific | 2025 |
| ALL Areas Construction Ltd | Construction | 2012 |
| ALL City Electrical Ltd | Construction | 2026 |
| ALL Day Play Limited | Arts & recreation | 2021 |
| ALL Housing Development Ltd | Construction | 2023 |
| ALL Saints Mews Residents Association Limited | Households | 1990 |
| Allimac Underwriting Limited | Financial services | 2009 |
| Allsecure Fire and Security Limited | Administrative & support | 2023 |
| Allsecure Services Limited | Administrative & support | 2000 |
| Allsteel Ltd | Manufacturing | 2024 |
| Almac Consulting Ltd | Professional & scientific | 2021 |
| Alona & Sons Ltd | Wholesale & retail | 2025 |
| Alpha Asset Finance Ltd | Financial services | 2018 |
| Alpha Asset Finance Property Ltd | Real estate | 2026 |
| Alpha Business Finance Ltd | Financial services | 2023 |
| Alpha Innovation Game Studios Ltd | Information & communication | 2015 |
| Alpinecove Limited | Financial services | 1986 |
| ALS Contracting Limited | Administrative & support | 2015 |
| Altay Steel Limited | Construction | 2019 |
| Alttio Ltd | Arts & recreation | 2019 |
| Alté Cuisine Ltd | Hospitality | 2025 |
| Always Creative Limited | Professional & scientific | 2023 |
| Alxisquer Ltd | Administrative & support | 2023 |
| AM Property Holdings Limited | Administrative & support | 2016 |
| Amaras Reset Studio Limited | Health & social care | 2026 |
| Amarga Construction Ltd | Construction | 2025 |
| Amazing Trading Limited | Wholesale & retail | 2023 |
| AMB Acupuncture Ltd | Health & social care | 2023 |
| Ambassador Construction Limited | Construction | 2022 |
| Amber and Black (Notts) Limited | Wholesale & retail | 2022 |
| Amber Hot Tubs & Pods Ltd | Wholesale & retail | 2022 |
| Amber Underwriting LLP | | 2009 |
| Amberly Property Improvement Ltd | Construction | 2023 |
| Amcilog Limited | Professional & scientific | 2022 |
| Amersham Shop Fitting Ltd | Construction | 2021 |
| AMF Barns Ltd | Real estate | 2020 |
| Amfb Management Co Limited | Households | 2020 |
| Amici Brickwork Contractors Ltd | Construction | 2009 |
| Amici Developments Midlands Limited | Construction | 2020 |
| Amitura Beauty Ltd | Wholesale & retail | 2025 |
| Amjr Consulting Ltd | Information & communication | 2019 |
| AMK Financial Management Limited | Financial services | 2012 |
| Amkcars Service Ltd | Wholesale & retail | 2026 |
| AML OIL and GAS Ltd | Professional & scientific | 2020 |
| AMM Invest Limited | Real estate | 2017 |
| Ampco 150 Limited | Financial services | 2019 |
| Ampco 170 Limited | Financial services | 2023 |