Valim will be replaced by the company’s chairman, José Carneiro da Cunha, with Oi giving no explanation as to the reason behind the management change.
The company has experienced poor financial performance, with consolidated net revenues for last year hitting $13.4 billion, below the company’s target.
The Wall Street Journal did point out the company was however just slightly shy of hitting other targets, including EBITDA and reducing net debt.
Valim has had to face challenges since his appointment as CEO in September 2011, including the consequences of the company’s acquisition of Brasil Telecom, and a share swap with Portugal Telecom.
Cunha is thought of as a temporary replacement at this stage.