MILAN - Trying to break into the clubby environment that is Italian high finance has never been easy, no matter how many millions of euros you have to throw at the effort.

That has not kept many from trying. The latest to gain prominence is Stefano Ricucci, who exploded onto the scene from relative obscurity in Rome to become the largest investor in the company that controls the Italian newspaper Corriere della Sera in the span of just a few months. He has also bought stakes of 5 percent in two Italian banks: Banca Antonveneta and Banca Nazionale del Lavoro.

Corriere della Sera, the biggest newspaper in Italy, is also considered by many to be its most influential daily and a shaper of public opinion. L'Espresso, one of Italy's most widely read newsweeklies, recently said: "Corriere is more than a newspaper. It is an institution, a formidable center of power controlled by the noble wing of the country's capitalist class."

The Italian press and some of the country's business leaders portray Ricucci, 42, as a parvenu. But some also see him as defending the national identity: the two banks are also the objects of takeover attempts by non-Italian buyers, and his stakes may help block the outsiders. No foreign investor has ever succeeded in buying an Italian bank.

Last month, Ricucci suggested that he might try to take over RCS Mediagroup, which owns Corriere della Sera and is controlled by a shareholder group that includes Fiat, Mediobanca, Assicurazioni Generali and Pirelli.

Ricucci, who now owns 18.1 percent of RCS, has said he wants to raise that stake to 20 percent. The RCS shareholder group, which owns 58 percent of the company's shares, has said it will not sell. In fact, the shareholders have said they would match any bidder's price and would sell their stakes to each other should any of them want to quit - a reaction that at least took Ricucci's moves seriously, though the shareholders did not name him.

RCS stock has risen 22 percent in the past month amid the speculation.

"The most probable outcome at this point is that somebody makes a takeover offer and tries to buy all of RCS," said Fabio Iannelli, an analyst at Caboto, the brokerage arm of Banca Intesa, Italy's largest bank and a member of the RCS shareholder group.

"If Ricucci makes the offer and he is successful, he could break up the company and sell it in pieces to make the most money possible. If instead the pact makes the takeover offer, then Ricucci could sell his stake and make a big capital gain."

The source of Ricucci's wealth has been a subject of debate in Italy over the past several months, despite his explanation that he is using money from successful real estate ventures in and around Rome. L'Espresso reported that Ricucci had obtained €1 billion, or $1.2 billion, in financing from Deutsche Bank and €800 million from Société Générale. His stakes in the two banks and RCS have a combined market value of €1.5 billion.

Ricucci's determination has led some to suspect that he has a supporter in the RCS shareholder group who will defect. Ricucci has said he is acting independently, but that has not stopped the speculation. Repeated attempts to contact Ricucci through his spokesman were unsuccessful.

Corriere della Sera has grown increasingly critical of Prime Minister Silvio Berlusconi during his four years in office. The only other national daily with a circulation and influence close to that of Corriere, La Repubblica, is fiercely anti-Berlusconi.

But the prime minister is not lacking for support in the media.

His brother runs a Milan-based national daily, and Berlusconi controls Italy's largest television company, Mediaset, which runs three of the eight national channels. He also has indirect control of the three state-owned television channels.