Dow Jones Newswires reports that Vivo Participacoes, Brazil’s largest mobile operator by subscribers, reported a four-fold increase in net profits in 1Q11, fuelled by an improvement in its operational performance and the reduction of its costs with depreciation. Vivo booked net profit of BRL710.2 million (USD438 million) in the period, up sharply from BRL191.9 million in the first three months of 2010, on revenue that climbed to BRL4.81 billion from BRL4.23 billion previously. The telco’s costs with depreciation and amortisation totalled BRL545.8 million, down from BRL871.3 million. EBITDA reached BRL1.65 billion from BRL1.27 billion a year ago; EBITDA margin was 34.3%, up from 30.1% in the year-earlier period. The cellco, which is controlled by Telefonica of Spain, ended the period with a total of 62 million clients, up from 53.9 million in the first quarter of 2010.