Citibank has instructed one of Switzerland's best-known law firms to defend it in what has been dubbed the biggest alleged fraud in Swiss private banking history.
Niederer Kraft & Frey will represent the bank later this year against a reclusive German millionaire who is suing for damages after attempts to reach a settlement failed.
Peter Mikutta, a self-made millionaire who moved to Switzerland after selling his data communications group, is claiming SFr44m (£18.4m) in damages against the US banking giant for dereliction of its fiduciary duties.
Zurich-based Werder Rechtsanwälte Solicitors (WRS), instructed by Mikutta, alleges that the bank accepted faxed instructions - sometimes involving multimillion-pound sums - without checking with the account holder in writing or verbally.
Niederer, founded in 1936, is expected to argue that Mikutta failed to notice his account being depleted even though he received regular performance updates.
Michael Werder, attorney-at-law from WRS, admitted that Mikutta contributed to his losses by failing to detect that his account was being drained, but said the firm will argue that the bank should not have allowed the transfers to occur.
In a separate but linked criminal case, Zurich prosecutors claim that a former Citibank employee who worked for Mikutta forged the millionaire's signature on documents in order to siphon off SFr114m (£47.8m) from his account.
It has been alleged that the transfers were approved as the defendant threatened to move Mikutta's account - one of Citibank's largest at the time - to another bank if the workers did not do as he wished.
The employee's current criminal lawyer, Tanja Knodel from Swiss firm Teitler Muller & Partner, would only comment to say that her client was innocent until proven guilty.
The bank said: "In the civil litigation against Citibank (Switzerland), we believe it is without merit and will defend ourselves vigorously."