* Telecom Italia at crossroads in Brazil after GVT bid fails
* Fossati welcomes Vivendi as likely Telecom Italia investor
* Says Tel. Italia should consider keeping Argentina stake (Adds more comments, context, comments on Telecom Argentina)
By Stefano Rebaudo
MILAN, Sept 2 (Reuters) - Telecom Italia investor Marco Fossati said on Tuesday any offer for TIM Brasil should value the Brazilian wireless company at around 11 times core earnings, or twice its current market value of 10 billion euros ($13 billion).
Takeover activity in Brazilian telecoms is heating up after Grupo Oi unveiled plans last week to bid for TIM Brasil and Telefonica started exclusive talks to buy broadband operator GVT from France's Vivendi.
"If Brazilian operators want to reduce the number of players to three from four, bagging enormous synergies, it would be better if they presented an offer that values TIM Brasil at 11 times its EBITDA," Fossati told Reuters in a phone interview.
"Otherwise we will not take it into consideration," said Fossati, the second-largest investor in Telecom Italia behind Telefonica with a stake of just under 5 percent held through holding Findim.
Telecom Italia CEO Marco Patuano, who is trying to get the company's towering debts under control and fund network improvements in Italy, has said he would consider selling TIM Brasil if the price is high enough.
That prospect appeared to move closer last week when Telecom Italia lost out to Telefonica in the bidding for GVT, denying TIM Brasil and its Italian parent a new avenue of growth in Brazil.
TIM Brasil, of which Telecom Italia owns around 67 percent, has a market value of around 5.4 times forward core earnings, according to Thomson Reuters Eikon data.
Brazil accounts for about one third of Telecom Italia's revenues. In spite of a recent economic slowdown, the Latin American country continues to be its main growth engine as Italy struggles to emerge from a long recession.
Sources with knowledge of the deal have said the aim of Oi is to bring in Mexico's America Movil and Telefonica in a deal to split TIM's assets three ways.
The Italian businessman welcomed the possible entry of Vivendi as a shareholder in Telecom Italia and the exit of Telefonica, which is now Telecom Italia's largest investor with an indirect stake of 14.8 percent.
Fossati has repeatedly criticised Telefonica's presence in Telecom Italia, saying the Spanish company had too much influence over its strategy in Latin America, where the two are rivals.
As part of its bid for GVT, Telefonica has offered Vivendi an option to buy an 8.3 percent voting stake in Telecom Italia. Sources close to the matter have said the French group, chaired by Vincent Bollore, will probably accept the stake.
Telefonica's Chairman Cesar Alierta said on Monday it planned to exit Telecom Italia once it has finalised the acquisition of GVT, ending an unprofitable seven-year investment and easing regulatory pressures in Brazil.
"Findim will welcome and support Bollore. We'll be a partner for them. We share the DNA and vision of Bollore and Vivendi," Fossati said.
He said the Italian company should consider keeping its stake in Telecom Argentina if an agreed sale to Mexican billionaire David Martinez continues to be delayed.
"I have always opposed the deal which I think does not fully price in the value of Telecom Argentina. If they continue to delay the sale, I would say let's keep it," he said. (1 US dollar = 0.7621 euro) (Writing by Danilo Masoni; editing by Tom Pfeiffer)