MILAN (Reuters) - The chairman of troubled Monte dei Paschi di Siena (>> Banca Monte dei Paschi di Siena SpA), Alessandro Profumo, said he will step down after Italy's third-biggest bank completes a 3 billion euro (2 billion pound) rights issue in the next few months.

The veteran Italian banker was named in 2012 to turn around the world's oldest bank after its costly acquisition of local rival Antonveneta as well as the euro zone debt crisis nearly triggered its collapse.

Monte Paschi has lost nearly 15 billion euros since 2011. It had already raised 5 billion euros in a capital increase as recently as last June, but it must again tap shareholders to plug a capital shortfall unearthed by a Europe-wide review of banks last year.

The fund raising must be completed by July. The Siena-based lender's five-century long independence is also about to end as it seeks a buyer to resolve its financial problems once and for all.

    "I consider my task at the bank will be concluded once the capital increase is done," Profumo told Italian daily Corriere della Sera in an interview published on Sunday.

"Let's say the road ahead now is charted, and if I may, even though the task is not a simple one, it has been made smoother."

His comments were confirmed by Monte dei Paschi.

Profumo, 58, was chief executive of UniCredit (>> UniCredit SpA) from 1997 to 2010 and the architect of its rise from regional bank to pan-European player.

During his tenure there he engineered one of Europe's biggest cross-border banking deals, the takeover of Germany's HVB in 2005.

Dubbed "Mr Arrogance" by some Italian media, Profumo never appeared at ease with the complex web of local patronage in Siena embodied by Monte dei Paschi and its former controlling shareholder, a banking foundation, bankers say.

But some of the bank's core shareholders said they had still hoped he would stay on and use his deal-making expertise to negotiate with potential bidders.

"I do not really have regrets. But it was not an easy ride," said Profumo, who renounced his salary as chairman while at the Tuscan bank.

During Profumo's stint, the Monte dei Paschi foundation was forced to loosen its grip on the bank and cut its stake to 2.5 percent from just under 50 percent to repay debts.

Monte dei Paschi, which was also hit by a scandal over loss-making derivatives trades negotiated by its former management, was the only Italian bank forced to resort to state aid as the euro zone's third-biggest economy teetered on the brink of a Greek-style debt crisis. It received a 4.1 billion euro bailout in 2013.

Still, it emerged as the weakest lender in European stress tests last year and is expected to carry out the new rights issue in late May or early June. The bank will finish repaying the state bailout after the new cash call.

Profumo said he was ready to help Monte Paschi find his successor and that the bank was on the right track. He said he wanted to become an entrepreneur, assisting and financing medium-sized businesses that want to grow.

(With additional reporting by Danilo Masoni; Editing by Keith Weir and Jane Baird)

By Silvia Aloisi

Stocks treated in this article : UniCredit SpA, Banca Monte dei Paschi di Siena SpA