Rome, June 11 - An Italian judge on Tuesday set September 26 as the trial date for Giuseppe Mussari, the former chairman of Monte dei Paschi di Siena (MPS), and two others on obstruction charges in connection with a huge financial scandal at Italy's third-biggest bank. Mussari, former MPS director-general Antonio Vigni, and former finance chief Gianluca Baldassarri were all ordered to stand trial on charges of obstructing bank supervisors. Those charges are in connection with the alleged concealment of a money-losing contract between MPS and Japanese investment bank Nomura. Investigations began early this year after it emerged that a previously undisclosed series of derivative and structured-finance deals produced losses of around 720 million euros for MPS, the world's oldest bank. Senior officials from MPS are facing penalties totalling as much as five million euros from the Bank of Italy for alleged fraud and corruption. Prosecutors say Nomura was involved in one of a series of suspect derivative and structured-finance deals involving MPS. The Japanese bank denies wrongdoing. Mussari, Vigni and Baldassarri are also being probed for crimes including usury, aggravated fraud, and issuing false statements. Mussari last year resigned from MPS and stepped down from his subsequent post as chairman of the banking association ABI after the scandal exploded in January. Baldassarri is under house arrest. There are also suspicions senior MPS managers were involved in alleged corruption in the nine-billion-euro acquisition of rival bank Antonveneta, at least two billion above its reputed market value, in 2008.