The Bank of Italy has fined former Monte dei Paschi di Siena board members and other managers involved in irregular structured trades more than 5 million euros, two sources close to the situation said on Thursday.

"The Bank of Italy imposed triple legal maximums against the former board of directors, the auditors and other members of high management for a total of about 5 million euros," one of the sources said.

Risky derivatives trades at Italy's third biggest lender, the subject of a criminal investigation in Siena, were partly responsible for huge losses that forced the bank to take a state bailout last month.

(Reporting by Silvia Ognibene; writing by Naomi O'Leary; Editing by Lisa Jucca)