Grillo won't hold office himself due to a manslaughter conviction for a 1981 traffic accident that left three dead.
Despite market unease over Italy's political gridlock, it will be weeks until President Giorgio Napolitano begins convening the parliamentary groups to form a government, after the newly elected parliament convenes on March 15 and elects its leaders.
In the jockeying ahead of the new legislature, the 64-year-old Grillo hasn't given up his edgy, biting tones or his uncompromising positions. So far he has been unwilling to become an ally of either of Italy's traditional parties â¿¿ the center-left led by Bersani or the conservatives led by former prime minister Silvio Berlusconi â¿¿ that he has harangued from his comic's stage for years.
"Bersani is a dead man talking," Grillo wrote on a blog post after the Democratic Party leader made overtures toward him. Grillo went on to call Bersani "a political stalker" for making "indecent proposals instead of stepping down, as anyone in his place would do. He managed to lose while winning."
Grillo says his forces will not vote to support any new government but would back legislation by conscience, one piece at a time. The withholding of a confidence vote limits the possibilities of forming a solid majority in the Senate, where the votes are split.
Bressanelli said one possible outcome is that Grillo could form a limited alliance with the center-left to achieve very specific agenda items before going into a new election soon.
Grillo has been clear about his goals. He wants to cut the number of parliamentarians in half, reduce their salaries, pay unemployed Italians a "citizen's stipend" of â¿¬1,000 ($1,300) a month, pass an anti-corruption law and create incentives to help the small businesses that power Italy's economy.
He also has called for a referendum on the euro currency shared by Italy and 16 other European nations.