The telecom firms did not disclose details of the offer. They said they asked Oi for the right to match potential offers it may have received in the competitive process for its assets.
Oi said there was a second offer, but it did not disclose details. It declined to comment further. According to two sources with knowledge of the matter, the other party is a foreign strategic player with a small presence in Brazil.
Oi will not choose the winner based solely on price but will also consider which group could secure regulatory approval for the deal faster, especially in terms of market concentration.
In a separate statement, Oi said it received a 1.08 billion-reais ($200.59 million) binding offer for its tower unit from Highline do Brasil II Infraestrutura de Telecomunicações S.A.
The Brazilian carrier set a minimum price of 15 billion reais ($2.79 billion) for its mobile assets. The company intends to use the proceeds of asset sales to fund its growing broadband fiber unit and pay off debt, aiming to exit bankruptcy protection. It was not clear if the offers met the minimum price.
TIM Brasil SA and Telefonica Brasil said in May they were planning a joint offer for Oi's mobile business, despite the COVID-19 outbreak, not mentioning Claro.
"The transaction, if completed, shall add value to all shareholders and clients by means of further growth, generation of operational efficiencies and service quality enhancement," the three bidders said in statements.
Oi, Brazil's largest fixed-line carrier had approximately 65 billion reais ($12.65 billion) of debt when it filed for bankruptcy protection.
($1 = 5.3842 reais)
(Reporting by Francesca Landini in Milan; and Carolina Mandl and Tatiana Bautzer in Sao Paulo; Editing by Ros Russell, Matthew Lewis and Cynthia Osterman)
By Carolina Mandl, Tatiana Bautzer and Francesca Landini