| Advanced Microcomputer Applications Limited | Administrative & support | 1987 |
| Advanced Molecular Diagnostics Ltd | Manufacturing | 2017 |
| Advanced Mortuary Systems Limited | Manufacturing | 1990 |
| Advanced NFT Solutions Group Limited | Information & communication | 2022 |
| Advanced Property Concepts Limited | Real estate | 2011 |
| Advanced Race Coaching Ltd | Arts & recreation | 2026 |
| Advanced Research & Technology Limited | Professional & scientific | 1998 |
| Advanced Residential Construction Limited | Construction | 2019 |
| Advanced Setting OUT Limited | Professional & scientific | 2026 |
| Advanced Software Ltd | Information & communication | 2000 |
| Advanced Tech LAB Ltd | Wholesale & retail | 2026 |
| Advanced Textile Solutions Ltd | Manufacturing | 2024 |
| Advanced Valve Solutions (UK) Limited | Wholesale & retail | 2005 |
| Advanced Vending Services Limited | Wholesale & retail | 2003 |
| Advanced Workforce Education Focus Academy CIC | Hospitality | 2024 |
| Advancehgvfleetwash Ltd | Administrative & support | 2026 |
| Advancing Innovations Limited | Administrative & support | 2010 |
| Advanta Productions Limited | Information & communication | 2004 |
| Advantage Auto Solutions Ltd | Wholesale & retail | 2020 |
| Advantage Engineering Solutions Ltd | Manufacturing | 2005 |
| Advantage Healthcare Limited | Administrative & support | 2004 |
| Advantage Healthcare Servco Limited | Professional & scientific | 2019 |
| Advantage Hub Ltd | Information & communication | 2010 |
| Advantage Services (Europe) Limited | Professional & scientific | 2002 |
| Advantage Services Limited | Other services | 2020 |
| Advantage Social Enterprise C.I.C. | Wholesale & retail | 2016 |
| Adventists in the City CIC | Other services | 2025 |
| Adventure Properties Ltd | Construction | 2016 |
| Adventureventure Ltd | Arts & recreation | 2022 |
| Advertising Box Limited | Professional & scientific | 2015 |
| Advertisingrebound Limited | Professional & scientific | 2025 |
| Advice and Guidance Project Ltd | Public administration | 2021 |
| Advice Local Ltd | Health & social care | 2024 |
| Advice With Accounts Nottingham Limited | Other services | 2019 |
| Advisory Crest Limited | Information & communication | 2025 |
| Advl Limited | Wholesale & retail | 2021 |
| Advocacyplus Ltd | Health & social care | 2013 |
| Advocate Neurodiversity Ltd | Education | 2025 |
| Advocate Services Ltd | Professional & scientific | 2019 |
| ADW Logistics Limited | Transport & logistics | 2016 |
| Adwise Limited | Professional & scientific | 2007 |
| ADX Investments Ltd | Real estate | 2022 |
| ADY Decorating Ltd | Construction | 2016 |
| Adydelivery Ltd | Transport & logistics | 2022 |
| Adzsell Car Hire Limited | Administrative & support | 2020 |
| AE Property Ltd | Real estate | 2023 |
| AE Sports and Remedial Massage Ltd | Health & social care | 2017 |
| Aear Properties Ltd | Real estate | 2026 |
| AEB Care Staffing Solutions Ltd | Administrative & support | 2023 |
| AEB Enterprises Ltd | Wholesale & retail | 2026 |
| AEB Project Solutions Ltd | Information & communication | 2023 |
| Aebal Leisure Ltd | Health & social care | 2023 |
| Aecsc Limited | Professional & scientific | 2022 |
| AED Properties Limited | Real estate | 2009 |
| Aedn LLP | | 2007 |
| Aedon Property Ltd | Real estate | 2019 |
| AEF Limited | Health & social care | 2024 |
| Aegir Design Ltd | Professional & scientific | 2019 |
| Aegis Business Services Ltd | Professional & scientific | 2020 |
| Aegis Electrotechnical Group Limited | Construction | 2026 |
| Aegis Peace Fund | Administrative & support | 2024 |
| Aegis People Limited | Professional & scientific | 2019 |
| Aegis Trust | Education | 2000 |
| Aegle Education Limited | Education | 2022 |
| AEH Estate Management Ltd | Real estate | 2023 |
| AEI Prospects Limited | Administrative & support | 2014 |
| Aejestates Limited | Real estate | 2021 |
| Aela Ltd | Education | 2024 |
| AEM Property Maintenance Limited | Households | 2024 |
| Aemon Ltd | Wholesale & retail | 2014 |
| Aeon Software Ltd | Information & communication | 2018 |
| Aequitas Advisory Ltd. | Professional & scientific | 2021 |
| Aerial Aspect Imaging Ltd. | Agriculture & fishing | 2014 |
| Aero EV Holdings Limited | Construction | 2024 |
| Aero EV Maintenance Ltd | Construction | 2018 |
| Aero EV Solutions Limited | Construction | 2013 |
| Aero Fabrications Limited | Manufacturing | 1993 |
| Aero Projects Limited | Construction | 2019 |
| Aero Property Limited | Wholesale & retail | 2021 |
| Aero Signature Services Ltd | Agriculture & fishing | 2025 |
| Aerocom (Holdings) Limited | Construction | 2021 |
| Aeroex Trading Ltd | Wholesale & retail | 2026 |
| Aeropadel Limited | Wholesale & retail | 2023 |
| Aerosonnets Limited | Manufacturing | 2022 |
| Aerospace Contracting Limited | Professional & scientific | 2018 |
| Aerowen Ltd | Professional & scientific | 2026 |
| AES Telecomms Ltd | Information & communication | 2019 |
| Aestetic Capricho Ltd | Other services | 2021 |
| Aesthetic Dental Zone Limited | Health & social care | 2017 |
| Aesthetic Education Limited | Education | 2018 |
| Aestheticad Digital Limited | Health & social care | 2021 |
| Aesthetics by Aneela Ltd | Other services | 2025 |
| Aesthetics by Annabelle Ltd | Other services | 2026 |
| Aesthetics Contour Ltd | Other services | 2025 |
| Aesthetics Nottingham Ltd | Other services | 2024 |
| Aether Interiors Limited | Wholesale & retail | 2026 |
| Aether Mediovent (Philips Menap) Limited | Manufacturing | 2021 |
| Aetherium Innovations Ltd | Administrative & support | 2026 |
| Aevoria Ltd | Health & social care | 2026 |
| AF & Sons Properties Ltd | Real estate | 2024 |