Intesa's bold gamble stuns cosy club of Italian finance

* Source says Intesa plans all-stock bid for Generali

* Complex deal would reshape Italian finance but faces hurdles

* Stakes high for Generali's top investor Mediobanca

By Silvia Aloisi and Paola Arosio

MILAN, Jan 30 (Reuters) - An expected bid by Intesa Sanpaolo , Italy's biggest retail bank, for the country's largest insurance company is a bold gamble that has stunned the cosy world of Italian finance and carries risks for both predator and prey.

The extent of what Intesa CEO Carlo Messina was planning dawned on Philippe Donnet, the French head of Generali , when he tried to check media reports that Intesa was preparing to build a stake in the insurer.

Donnet called his counterparts at Intesa on Jan. 23, according to two sources close to the matter, but no one was available to take his call.

It was a sign the gloves were off in the so-called salotto buono, or drawing room, the informal club that has pulled the strings in Italian business and banking since World War Two.

Bonnet's riposte on the same day was to buy a 3 percent stake in Intesa. Under Italian cross-shareholding rules, Intesa would now have to buy at least 60 percent of Generali if it made a bid.

By threatening Generali, one of Italy's most venerable institutions, Messina is also opening up a front against merchant bank Mediobanca - the power behind the throne at Generali with a 13 percent stake. Mediobanca's own biggest investor is Intesa's domestic arch-rival UniCredit.

"This is Messina's boldest move, I have a lot of respect for him but he's putting his entire career at risk on a deal of this magnitude," said a senior banker.

As the week unfolded, Intesa eventually acknowledged it was looking at a possible deal with Generali, though Messina said on Thursday the bank would take its time. Sources say Intesa is considering an all-stock bid for the insurer in a deal that would create a powerhouse with a market value of more than 60 billion euros.

Intesa felt it had to jump in because it feared Generali, long regarded as a takeover target, could fall in the hands of a foreign predator and create a big asset management competitor on Intesa's home turf, the sources said.

The government has come under pressure to ensure Generali remains Italian but has said it is unwilling to intervene.

Intesa is a rarity among Italian banks - profitable and well capitalised. While its largest rivals, UniCredit and Monte dei Paschi, are striving to turn around under the weight of billions of euros worth of bad loans, Intesa has been able to pay generous dividends despite Italy's economic downturn.