| Acute Gym Services Ltd | Leeds | 2019 |
| Acute Medicine East Anglia Limited | Cambridge | 2009 |
| Acutech Precision Engineering Limited | Attleborough | 2016 |
| Acutek Limited | Accrington | 2014 |
| Acutension Limited | Telford | 2019 |
| Acutools Limited | Accrington | 2014 |
| Acuvent Engineering Group Ltd | Dundee | 2016 |
| Acuvista Technologies Ltd | London | 2025 |
| ACV Engineering Ltd | Ashbourne | 2011 |
| Acvedc Company Ltd | Chelmsford | 2021 |
| Acvr Service and Maintenance Limited | Birstall | 2024 |
| ACW Aviation Limited | Rotherham | 2013 |
| ACW Electrical Suffolk Ltd | Ipswich | 2013 |
| ACW Motorsport Plastics Ltd | Leamington Spa | 2014 |
| ACY Air Conditioning & Refridgeration Ltd | Margate | 2018 |
| ACZ Composites Ltd | Cambridge | 2018 |
| ACZ Ltd | London | 2019 |
| AD and C Electrical Services Ltd | Cannock | 2013 |
| AD Art Design Limited | Bristol | 1991 |
| AD Astra Avionics Ltd | Stowmarket | 2016 |
| AD Astra Cider Ltd | Axbridge | 2021 |
| AD Automotive Ltd | Waterlooville | 2023 |
| AD Brothers Ltd | London | 2023 |
| AD BUD Ltd | West Calder | 2019 |
| AD Commerce Ltd | Warwick | 2026 |
| AD Cooling Ltd | Blackpool | 2021 |
| AD Cortez Limited | Antrim | 2024 |
| AD Creations Limited | South Croydon | 2008 |
| AD Electronic Design Ltd | Rotherham | 2022 |
| AD Energy (NI) Limited | Belfast | 2014 |
| AD Engineering Limited | Stowmarket | 2025 |
| AD Fabrication Limited | Maldon | 1991 |
| AD Fabs (Engineering) Ltd | Bradford | 2015 |
| AD Fine Jewels Ltd | Burnley | 2026 |
| AD Finn Ltd | London | 2026 |
| AD Furnishings Ltd | Stratford-Upon-Avon | 2026 |
| AD G London Ltd | London | 2018 |
| AD Gefrin Distillery Limited | Northumberland | 2018 |
| AD Graphics Limited | Redhill | 2018 |
| AD Group of Companies Limited | Middlesbrough | 2025 |
| AD Hire Ltd | Crewe | 2021 |
| AD HOC Designs Limited | Cardiff | 2004 |
| AD Innovation Electric Limited | London | 2015 |
| AD Laser Cutting Ltd | Rochdale | 2023 |
| AD Leading Limited | Basingstoke | 2021 |
| AD Lift Services Limited | West Hallam | 2025 |
| AD Machine Services Ltd | Sutton Coldfield | 2017 |
| AD Manufacturing Ltd | Wolverhampton | 2023 |
| AD Marine Electrical Repairs Limited | Newton Aycliffe | 2018 |
| AD Media Agency Ltd | London | 2022 |
| AD Metal Fabrications (Livingston) Ltd | Livingston | 2009 |
| AD Metalwork Solutions Ltd | Dudley | 2016 |
| AD Miniprints Limited | Alfreton | 2026 |
| AD OU Ltd | London | 2025 |
| AD Pipework Limited | Wakefield | 2014 |
| AD Plastics Ltd | Colnebrook | 2003 |
| AD Precision Ltd | Cardiff | 2015 |
| AD Pro Energy Ltd | Frome | 2023 |
| AD Saini Ltd | Feltham | 2025 |
| AD Series Displays Manufacturing Ltd. | Tonbridge | 2011 |
| AD Sherburn Limited | London | 2025 |
| AD Shorrock Ltd | Preston | 2012 |
| AD Technical & Safety Services Ltd | Stockton On Tees | 2011 |
| AD Total FAB Ltd | Harlow | 2021 |
| AD Trading Group Ltd | Kington | 2026 |
| AD Ventilation Limited | Jarrow | 2006 |
| AD Venture Signs & Image Ltd | Consett | 2020 |
| AD Victoriam Limited | Durham | 2018 |
| AD Welding Services Ltd | York | 2023 |
| AD Worktops Ltd | Enfield | 2025 |
| Ad-Fab Notts Limited | Nottingham | 2003 |
| Ad-Pro Safe Ltd | London | 2025 |
| Ad-Prod Limited | Standon | 2008 |
| Ad-Tech Europe Limited | Sully | 2006 |
| Ad-Tek Finishings Limited | Braintree | 2003 |
| Ad-Tek Products Limited | Braintree | 2000 |
| Ad-Uk ALL Doors UK Ltd | Manchester | 2021 |
| Ad-Uk Industrial Doors & Security Shutters Ltd | Manchester | 2020 |
| Ad.Plasterers Ltd | Huddersfield | 2025 |
| AD3 Envelope Printers Limited | Leeds | 2005 |
| Ad@M Ltd | Caerphilly | 2020 |
| ADA Bespoke, Carpentry and Joinery Ltd | Wallasey | 2025 |
| ADA Cavendish Group Ltd | Cardiff | 2017 |
| ADA Denis Ltd | London | 2025 |
| ADA Design Studio Limited | London | 2023 |
| ADA Engineering Electrical-Electronic Systems Ltd | London | 2020 |
| ADA Fabrication Ltd | Hull | 2026 |
| ADA Food and Beverage Ltd | Cambridge | 2024 |
| ADA Jewellery Limited | Waltham Cross | 2026 |
| ADA Marketing Limited | Burnley | 2024 |
| ADA Services (N.I.) Limited | Larne | 2017 |
| ADA Technology Limited | London | 2022 |
| Ada's Ice Cream & Sweet Treats Limited | Faversham | 2025 |
| Adaab Knitwear Ltd | Oldham | 2024 |
| Adad Energy Technology Co., Ltd | Beckenham | 2021 |
| Adaero Precision Components Limited | Crediton | 1997 |
| Adage Engineering Limited | Devizes | 2008 |
| Adair Dental Laboratory Ltd. | Edinburgh | 2009 |
| Adair Engineering Ltd | Lanark | 2016 |
| Adajio Limited | London | 2009 |