Brazilian telecommunications provider Oi SA (OIBR4.SA) said on Monday it has not entered into any agreement to join a group of rivals to buy Telecom Italia SpA's (TLIT.MI) stake in Brazilian phone company TIM Participacoes SA TIMP4.SA.

"As of this date there has not been any definition or accord with relation to a structure for this operation, nor have any instruments or proposals outlining such an operation been signed," Oi said in a statement responding to questions from Brazil's securities regulator, the CVM.

In August Oi announced that it had hired Grupo BTG Pactual (BBTG11.SA) to act as its representative and develop plans for a possible purchase of Telecom Italia's stake in TIM Participacoes.

"Contact with other participants in the market that might be interested in this operation is one of the roles for BTG Pactual in its position of the company's representative in the operation," the statement said.

The statement was made in response to the regulator's questions about an article published in the Folha de S. Paulo newspaper on Friday saying that Oi; Vivo (VIVT4.SA), controlled by Spain's Telefonica SA (TEF.MC); and Claro, controlled by Mexican billionaire Carlos Slim's America Movil SAB (AMXL.MX), had agreed to make a joint offer for TIM Participacoes.

Also on Friday, Reuters reported that two sources with direct knowledge of the subject confirmed that Oi, America Movil and Telefonica plan a joint offer for TIM Participacoes.

Oi has lost 81 percent of its value in the last 10 years, the worst-performing company on Brazil's benchmark Bovespa stock index over the last 10 years. TIM Participacoes, meanwhile, has seen its share price rise nearly five-fold in the same period.