The former CFO of TIM's parent company, Telecom Italia, will depart on March 4.
Mangoni replaced Luca Luciani, who stepped down from his post last May after being implicated in a scandal involving the falsification of prepaid SIM cards to inflate Telecom Italia’s subscriber base.
In a statement TIM said Mangoni announced his resignation at the end of a meeting held on Tuesday, called to discuss the company’s fourth quarter financial results.
Mangoni said he had accomplished the task that had been assigned to him to command a smooth transition in the management of the company.
TIM recorded a 16.4% rise in fourth quarter net profit attributed to higher services and products sales.. The company’s revenue was up 8.2% to R$7.34 and net profit for 2012 rose 13.4% to R$1.45 billion.
TIM said it would announce a replacement as soon as possible. Some reports suggest that TIM is looking for a Brazilian executive with no links to parent company Telecom Italia.