Addleshaw Booth & Co has won Leeds United as a new client
The firm's sports unit has scooped an instruction to review the transfer of defender Rio Ferdinand from West Ham United to Leeds United in November 2000.
Leeds United has a relationship with partner Andrew Price, who joined Addleshaws at the end of last year from the Leeds office of national rival DLA, where he was head of the sports business group.
The Leeds United board appointed Addleshaws alongside its auditors Deloitte & Touche amid press allegations that the £17.5m transfer was not completed in accordance with the club's policies.
In a statement, Leeds United confirmed: "The expenditure and payments for the transfer, including agent's fees, were properly authorised in accordance with Leeds United policy. The Audit Committee can also confirm that there is no evidence of any financial impropriety or lack of financial control."
Addleshaws' sports unit advises a number of other football clubs, including Manchester City and Celtic. The unit also helped Manchester United on the launch of MU Finance, which is looking to develop Manchester United-branded credit cards among other financial products. Addleshaws is also advising Manchester United on how it can exploit data on members to market the products.