Italian bank Monte dei Paschi said on Friday it is considering legal action against anyone who damages its commercial activity or spreads false information about the bank.
In a statement, the bank said it had become the target of "attacks of various kinds involving, in certain circumstances, employees, creating considerable problems in the normal course of business.
It said it was considering civil and penal action.
Italy's third-biggest lender is at the center of a widening scandal over concealed derivatives trades. The bank is dependent on 3.9 billion euros of state loans.
The derivative trades are at the heart of a fraud probe into former management of the world's oldest bank and have raised doubts about the effectiveness of banking supervisors and the role of politicians, who agreed the state bailout for the bank.
(Reporting by Francesca Landini)