| Ability Beams Ltd | Health & social care | 2024 |
| Abitat Development Ltd | Information & communication | 2025 |
| Ablesoft Solutions Limited | Information & communication | 2024 |
| Abmj Tech Ltd | Information & communication | 2025 |
| Abode Estates Limited | Real estate | 2021 |
| ABS Build Holdings Limited | Construction | 2022 |
| ABS Versa Ltd | Wholesale & retail | 2026 |
| Absconder Limited | Wholesale & retail | 2025 |
| Abundance Innovations Ltd | Wholesale & retail | 2025 |
| AC Strategic Projects Ltd | Professional & scientific | 2026 |
| Academie TIK Ltd | Wholesale & retail | 2025 |
| Academy of Business, Finance and Artificial Intelligence Ltd | Professional & scientific | 2024 |
| Acasia Studios Limited | Wholesale & retail | 2026 |
| ACC Training Solutions Ltd | Financial services | 2015 |
| Accents Studio Ltd | Wholesale & retail | 2025 |
| Access and Countryside Management Ltd | Professional & scientific | 2015 |
| Access My Care Ltd | Information & communication | 2022 |
| Accredonet UK Ltd | Real estate | 2026 |
| Accrio Ltd | Professional & scientific | 2025 |
| Accur Capital Ltd | Financial services | 2022 |
| Accurex Solutions Ltd | Professional & scientific | 2025 |
| Accurite Ltd | Households | 2025 |
| Ace + James Ltd | Information & communication | 2019 |
| Ace Consumer Essentials Ltd | Wholesale & retail | 2025 |
| Ace Proficiency Ltd | Manufacturing | 2026 |
| Ace Revision Ltd | Education | 2024 |
| Acehcom Ltd | Wholesale & retail | 2025 |
| Acespace Limited | Information & communication | 2023 |
| ACM Private Limited | Professional & scientific | 2025 |
| ACM Supplies Ltd | Wholesale & retail | 2025 |
| Acociacion Green Rude Life Ltd | Wholesale & retail | 2025 |
| ACORN2OAK Ventures Limited | Wholesale & retail | 2024 |
| Acorrza Limited | Health & social care | 2021 |
| Action Figure Cellar Ltd | Wholesale & retail | 2022 |
| Action for People CIC | Information & communication | 2015 |
| Active Hearts and Minds Limited | Other services | 2024 |
| Active Marketing Masters Ltd | Professional & scientific | 2025 |
| Activedots Ltd | Information & communication | 2026 |
| Acuitus Evaluations Ltd | Professional & scientific | 2025 |
| AD BUS Preservation Limited | Transport & logistics | 2026 |
| AD Coherent Accounts Ltd | Professional & scientific | 2026 |
| AD Renov Ltd | Construction | 2026 |
| Adak Consultancy and Online Shopping Ltd | Wholesale & retail | 2026 |
| Adam Health and Wellbeing Limited | Health & social care | 2025 |
| Adam Plater Woodworks Ltd | Manufacturing | 2025 |
| Adapt and Flow CIC | Health & social care | 2025 |
| ADAPTIVE8 Ltd | Information & communication | 2024 |
| Addaptable Ltd | Information & communication | 2024 |
| Adderley Travel Limited | Transport & logistics | 1999 |
| Addison Kate Ltd | Transport & logistics | 2026 |
| Adeleda Ltd | Education | 2021 |
| Ademz Ltd | Wholesale & retail | 2025 |
| Adeola Adekunle Popoola Ltd | Extraterritorial | 2025 |
| Adepto Consulting and Media Limited | Information & communication | 2020 |
| Adesha Beauty Ltd | Wholesale & retail | 2019 |
| Adhdaptive Ltd | Professional & scientific | 2024 |
| Adjumento Limited | Information & communication | 2024 |
| ADK Financial Ltd | Wholesale & retail | 2025 |
| Adler Rowe Ltd | Wholesale & retail | 2025 |
| Adlo Consulting Ltd | Professional & scientific | 2024 |
| Admaxia Ltd | Wholesale & retail | 2023 |
| Admin Shrub Limited | Public administration | 2025 |
| Admos AI Ltd | Professional & scientific | 2025 |
| Adora Moments Ltd | Information & communication | 2025 |
| Adplusmedia Ltd | Professional & scientific | 2026 |
| Adrian Dews Ltd | Professional & scientific | 2025 |
| ADS Aligned Ltd | Professional & scientific | 2024 |
| Adservo Ltd | Health & social care | 2024 |
| Adtoker Ltd | Wholesale & retail | 2023 |
| Adura Marketing Limited | Professional & scientific | 2022 |
| Advance Business Consultants Ltd | Professional & scientific | 2023 |
| Advanced Additive Manufacturing Technology Ltd | Information & communication | 2025 |
| Advanced Autoz Ltd | Professional & scientific | 2022 |
| Advanced Client Ltd | Professional & scientific | 2024 |
| Advanced Solutions for International Development Ltd | Information & communication | 2018 |
| Advanced Tech Star Ltd | Wholesale & retail | 2025 |
| Advanced Urology Clinical Solutions Ltd | Health & social care | 2026 |
| Adventure Women UK Ltd | Administrative & support | 2026 |
| Advocate Collaborate Educate Limited | Health & social care | 2025 |
| Advrting Group Ltd | Wholesale & retail | 2022 |
| ADW Advisory Services Ltd. | Public administration | 2024 |
| AE Window Cleaning Service Ltd | Administrative & support | 2023 |
| AEA Consulting Limited | Professional & scientific | 2009 |
| Aegeantreasures Ltd | Wholesale & retail | 2023 |
| Aegis Control Solutions Limited | Manufacturing | 2026 |
| Aegis Elite Solutions Ltd | Administrative & support | 2024 |
| Aegisbuild Ltd | Information & communication | 2025 |
| Aegisx Ltd | Information & communication | 2025 |
| Aergod Limited | Information & communication | 2021 |
| Aerial Ashes Ltd | Other services | 2020 |
| AEROFLEX31 Ltd | Manufacturing | 2025 |
| Aerosnap Ltd | Professional & scientific | 2026 |
| Aeroworks Aviation Ltd | Transport & logistics | 2023 |
| Aesthetic Teeth Clinic Ltd | Health & social care | 2023 |
| Aethel Systems Ltd | Information & communication | 2026 |
| Aether Architectural Design Ltd | Information & communication | 2026 |
| Aetherium Solutions Ltd | Information & communication | 2024 |
| Aethryna Digital Skills Co-Op CIC | Education | 2026 |
| Afaq Nawaz AMZ Store Ltd | Wholesale & retail | 2025 |
| AFC Consultancy Group Ltd | Professional & scientific | 2026 |