(ANSA) - Rome, December 17 - The chairman of Italy's scandal-ridden Monte dei Paschi di Siena (MPS) bank on Tuesday said shareholders must vote to recapitalize in January or see the firm nationalized. "We will work through December 30 to make the capital increase happen," Chairman Alessandro Profumo told reporters in an interview. Asked whether he would resign should majority shareholder Monte dei Paschi Foundation succeed in delaying the move to May, Profumo replied, "the Foundation's vote at the shareholders meeting will be crucial. Let's see what happens then". MPS already had to recapitalize in 2012, when it lost over $2 billion in the first half in the wake of rising yields and declining valuations on Italian government debt. It did so again in January 2013, when news went public that top management had entered into secret derivatives contracts with Deutsche Bank and Nomura in order to hide estimated losses of 500-750 million euros in two of its divisions. The firm sparked fresh controversy this year when it was accused of misleading Italy's market regulator in October 2012, shortly before it received a 4.1-billion-euro State bailout. MPS is already at the center of a judicial investigation into its acquisition of smaller rival Antonveneta in 2008 as well as the derivatives trades the bank allegedly used to conceal losses. Former Chairman Giuseppe Mussari and former director general Antonio Vigni, who left in early 2012, are both under investigation for market manipulation, false statements to the market and regulatory obstruction in relation to the Antonveneta deal and the derivatives trades. Both deny any wrongdoing. Founded in 1472 by the magistrate of the city state of Siena, MPS is the oldest surviving bank in the world and Italy's third-largest bank.