| Acfi Facades Limited | Construction | 2018 |
| Acford Design Services Limited | Manufacturing | 1992 |
| ACH Hollingsworth Ltd | Administrative & support | 2025 |
| Achieve Wellness Ltd | Education | 2013 |
| Achieve With ANA Limited | Education | 2024 |
| Achimandrei Ltd | Transport & logistics | 2023 |
| ACJ Construction Group Ltd | Construction | 2023 |
| ACJ Design Ltd | Information & communication | 2014 |
| Acjj Limited | Administrative & support | 2020 |
| ACK Malta Holdings Limited | Financial services | 2022 |
| Acktrio Ltd | Information & communication | 2024 |
| ACL Auto Services Ltd | Wholesale & retail | 2019 |
| ACN Technology Limited | Administrative & support | 2016 |
| ACO Haulage Ltd | Transport & logistics | 2023 |
| Acocks Green Cake Box Limited | Wholesale & retail | 2018 |
| Acorn Education Ltd | Education | 2015 |
| Acorn Estates Midlands Limited | Real estate | 2015 |
| Acorn Fundraising & Consultancy Ltd | Professional & scientific | 2017 |
| Acorn Leaf Care Ltd | Health & social care | 2022 |
| Acorn Printing Services Limited | Administrative & support | 2002 |
| Acorns Estates Limited | Real estate | 2016 |
| Acorns Properties UK Ltd | Real estate | 2016 |
| Acoustic Camera UK Ltd | Wholesale & retail | 2019 |
| ACP Facade Services Ltd | Manufacturing | 2019 |
| Acpmis Limited | Construction | 2012 |
| Acquah & Co Ltd | Transport & logistics | 2021 |
| Acquah Analytics Ltd | Arts & recreation | 2014 |
| Acreonix Ltd | Information & communication | 2026 |
| Acrichardson Property Development Ltd | Real estate | 2025 |
| Across the Pond Travel Limited | Administrative & support | 2024 |
| Acs-Tech Limited | Professional & scientific | 2014 |
| ACT Delivery Limited | Transport & logistics | 2026 |
| ACT Solutions Ltd | Education | 2025 |
| Acti-Vape UK Limited | Wholesale & retail | 2015 |
| Action Artificial Intelligence Limited | Professional & scientific | 2015 |
| Action Family Network C.I.C. | Education | 2022 |
| Action Reaction Theatre Company CIC | Arts & recreation | 2026 |
| Action-Sealtite Limited | Wholesale & retail | 1982 |
| Actionphysio Limited | Health & social care | 2006 |
| Activate Clinical Research Holdings Ltd | Financial services | 2024 |
| Activate Clinical Research Ltd | Health & social care | 2024 |
| Activate Global Limited | Administrative & support | 2026 |
| Activate Your Potential Ltd | Transport & logistics | 2021 |
| Active CARE24 Ltd | Public administration | 2021 |
| Active Communications Limited | Information & communication | 2005 |
| Active Crane Hire Ltd | Administrative & support | 2015 |
| Active Inclusion Network CIC | Arts & recreation | 2021 |
| Active Processes Ltd | Information & communication | 2016 |
| Active Property Investment Limited | Professional & scientific | 2015 |
| Active Training and Education | Arts & recreation | 1997 |
| Active Tunnelling Limited | Construction | 1994 |
| Active Virtue Ltd | Manufacturing | 2023 |
| Activeways Ltd | Health & social care | 2018 |
| Activity Advisor Limited | Arts & recreation | 2006 |
| Activity Club Coventry Limited | Administrative & support | 2011 |
| Activity Street Limited | Education | 2019 |
| Acton Grange Investments Limited | Financial services | 2020 |
| Acton Properties (Coventry) Limited | Real estate | 2017 |
| Acton Ventures Limited | Administrative & support | 2011 |
| Actual Factual Limited | Professional & scientific | 2020 |
| Actual First AID Limited | Health & social care | 2023 |
| Acuity Commodities Limited | Financial services | 2015 |
| Acytar Limited | Real estate | 2011 |
| AD & SK Property Ltd | Real estate | 2022 |
| AD Homes (Midlands) Limited | Construction | 2023 |
| AD Investments (Midlands) Limited | Real estate | 2023 |
| AD Key Properties Limited | Real estate | 2021 |
| AD Mobile Services Ltd | Extraterritorial | 2016 |
| Ad's Garden Services Ltd | Administrative & support | 2007 |
| Ad-No Construction Ltd | Construction | 2022 |
| ADA & Somerville Ltd | Real estate | 2023 |
| ADA Coventry CIC | Hospitality | 2025 |
| Adair Richards Associates Ltd | Professional & scientific | 2010 |
| Adam Ayres Ltd | Financial services | 2021 |
| Adam Brown Chef Limited | Hospitality | 2013 |
| Adam Cleaning Service Limited | Administrative & support | 2025 |
| Adam Maria Transport Ltd | Construction | 2025 |
| Adam Rogo Ltd | Manufacturing | 2022 |
| Adamal Limited | Real estate | 2021 |
| Adams Sports Academy Limited | Education | 2019 |
| Adamscreate Limited | Wholesale & retail | 2015 |
| Adana FM24/7 Ltd | Administrative & support | 2025 |
| Adanak Limited | Health & social care | 2023 |
| Adaptive AI Ltd | Information & communication | 2023 |
| Adaptive Mountain Ltd | Information & communication | 2021 |
| Adaptive Technology Ltd | Information & communication | 2009 |
| Adas Property Ltd | Real estate | 2024 |
| Adastra General Limited | Households | 2020 |
| ADB Solutions Ltd | Transport & logistics | 2025 |
| ADC Global Enterprises Ltd | Administrative & support | 2018 |
| ADD MOR Homes Ltd | Real estate | 2023 |
| Adda Catering Ltd | Wholesale & retail | 2025 |
| Addcare Ltd | Public administration | 2021 |
| Addiction Recovery Solutions Ltd | Health & social care | 2018 |
| ADE & LEO Ltd | Transport & logistics | 2019 |
| ADE Accounting Limited | Professional & scientific | 2016 |
| ADE Plaza Limited | Wholesale & retail | 2025 |
| ADE Transport Ltd | Other services | 2018 |
| Adebimpe Ajibade Ltd | Health & social care | 2023 |
| Adebum & Sons Limited | Real estate | 2022 |