| A, P & C Holdings Ltd | Hounslow | 2019 |
| A-Ag Holdco, Limited | London | 2024 |
| A-Ag Midco, Limited | London | 2024 |
| A-Ag Topco, Limited | London | 2024 |
| A-Alliance UK Ltd | London | 2015 |
| A-Arora Limited | London | 2023 |
| A-Chem Holdings Limited | Alfreton | 2026 |
| A-Gas Bidco Limited | Bristol | 2017 |
| A-Granite Limited | Doncaster | 2012 |
| A-Kjgroup Limited | Paisley | 2026 |
| A-One Control Holdings Ltd | Armagh | 2025 |
| A-Plan Group Ltd | London | 2014 |
| A-Plan Holdings | Witney | 1963 |
| A-Plan Limited | London | 1993 |
| A-Point Marketing Ltd | London | 2018 |
| A-Pro Associates Limited | Guildford | 2023 |
| A-S Technical Group Ltd | Liverpool | 2023 |
| A-Six Ventures Ltd | London | 2023 |
| A-Star Financial Solutions UK Ltd | Hayes | 2012 |
| A-Stat Edtech Ltd | Wolverhampton | 2025 |
| A-Stat Holdings Limited | Wolverhampton | 2020 |
| A-Tac Holdings Limited | London | 2022 |
| A-Technologies Holdings Limited | London | 2019 |
| A-Technologies Limited | Stockton-On-Tees | 2019 |
| A-Triangle Holdings Ltd | Thornton Cleveleys | 2022 |
| A-Z D&F Holdings Limited | Lincoln | 2023 |
| A-Z Holdings Ltd | Norwich | 2019 |
| A-Z Motor Spares Holdings Ltd | Stafford | 2024 |
| A-Z Strategy & Corporate Finance Limited | Aylesbury | 2024 |
| A-Z Treasury Services Ltd | York | 2014 |
| A. & Advice Ltd | London | 2023 |
| A. & R. Corner Limited | Hampton | 1992 |
| A. 1. Brokers Limited | Ballymena | 1983 |
| A. Alexander Group Ltd | Glasgow | 2024 |
| A. and B. Millar (Holdings) Limited | Fivemiletown | 2018 |
| A. Bianchi Financial Solutions Limited | Leeds | 2006 |
| A. Black Properties Limited | London | 2016 |
| A. Bruce Limited | | 1926 |
| A. C. Farnsworth Limited | Derby | 2003 |
| A. Clarke & Co. (Smethwick) Holdings Limited | Oldbury | 2023 |
| A. Count 'N' C Ltd | Chesterfield | 2009 |
| A. Croot Enterprise Ltd | Taunton | 2024 |
| A. D. Adams & Co Ltd | Bristol | 2024 |
| A. Dyson & SON (Patterns) Limited | West Yorkshire | 1978 |
| A. E. Sharp Limited | Stratford Upon Avon | 2011 |
| A. E. Taylor Financial Services Limited | Sale | 1998 |
| A. Franks & SON | | 1958 |
| A. Holmes Group Ltd | Ballyclare | 2022 |
| A. Hosie Limited | Totnes | 2002 |
| A. Hurworth (N.E.) Limited | Darlington | 2025 |
| A. J. F Advisors Ltd | London | 2023 |
| A. J. L. Holdings Norfolk Limited | Norwich | 2018 |
| A. J. LEE & Associates Limited | Salford | 2010 |
| A. Jones Group Limited | London | 2025 |
| A. Joyce & SON Limited | Shepperton | 1965 |
| A. Kosijer and Family C&C Ltd | London | 2026 |
| A. Lomas Limited | Oxford | 1953 |
| A. M. C. Diesel Engineering Limited | Preston | 1987 |
| A. M. Insolvency Limited | Brighouse | 2015 |
| A. Manning U.K. Limited | Oxfordshire | 1984 |
| A. Nice (Holdings) Limited | Basingstoke | 1992 |
| A. P. Jenkins and Associates Limited | Lincoln | 2013 |
| A. P. MOY Financial Ltd | Worthing | 2014 |
| A. R. Haddy & SON Holdings Limited | Saltash | 2016 |
| A. R. Trading HK Limited | Cardiff | 2024 |
| A. R. Z. Limited | London | 2014 |
| A. Ransley Limited | Bromley | 2003 |
| A. S. Capital Ltd | London | 2025 |
| A. S. Facer (Longton) Holdings Limited | Preston | 2018 |
| A. S. Group Management Limited | Wednesbury | 1965 |
| A. Sesay Enterprises Ltd | London | 2026 |
| A. T. Griffith Limited | London | 2012 |
| A. Tilley Roofing Holdings Limited | Newcastle Upon Tyne | 2024 |
| A. Valiant Holdings Limited | Bury St. Edmunds | 2019 |
| A. W. Ellis Limited | Nottingham | 2009 |
| A. Weld (Holdings) Limited | Neath | 2018 |
| A.A. Bramall Holdings Limited | Burton-On-Trent | 1984 |
| A.A. Scott Holdings Ltd | Carluke | 2019 |
| A.A.A Financial Ltd | Maidenhead | 2025 |
| A.A.K Holdings Limited | Leeds | 2017 |
| A.A.S Holds Ltd | Morden | 2024 |
| A.A.S Ventures | Melton Mowbray | 2020 |
| A.Al-Asady Holdings Limited | London | 2024 |
| A.B. Dick-Cleland (Underwriting Agencies) Limited | London | 1963 |
| A.B. Group (Croydon) Limited | Croydon | 1959 |
| A.B. Produce Trading Limited | London | 2006 |
| A.B. Terratec (Holdings) Limited | Halifax | 2026 |
| A.B.C. Stainless (Holdings) Limited | Peterborough | 2008 |
| A.B.I. Electronics (Holdings) Limited | Barnsley | 2013 |
| A.Bilbrough & Co.Limited | | 1911 |
| A.C. Bacon Engineering (Holdings) Ltd | Norwich | 2016 |
| A.C. Flynn Group Ltd | Birkenhead | 2023 |
| A.C. Holdings Group Limited | Wath | 2017 |
| A.C. Lessels Holdings Ltd. | Edinburgh | 2025 |
| A.C. Sovereign Financial Services Limited | Cadnam | 2004 |
| A.C.K.G Holdings Limited | Reading | 2025 |
| A.C.M. (Yorkshire) Holdings Limited | Garforth | 2024 |
| A.C.M. Financial Services Ltd. | Stockport | 1999 |
| A.C.Properties(Acton)Limited | Ealing | 1946 |
| A.C.S. Holdings Limited | Liverpool | 1985 |