2002-2016Wolff Olins. The logo, resembles a speech bubble, used in many different shapes. In 2007, all their services rebranded under Oi, and in 2012, the company's corporate name was changed from Telemar Norte Leste S.A. to Oi S.A.
In March 2016, Oi refreshed their existing brand by literally making it more flexible. The bubble that encases the brand name can now become freeform and comes in one of three possible graduated finishes. The final package of branding consists of about 70 variations (regarding each logo is restrained to it's given gradient as shown below).