The announcement took the market by surprise. Since joining in 2004, Flint had a successful record at building a company 50:50 owned by companies with very different cultures. Flint said he is planning a short career break before deciding on his next steps.
Last year Sony Ericsson increased the number of handsets shipped by 46% to 74.8 million and increased net income 185% to 997m euros ($1.36bn) on sales that rose 50.7% to 10.9bn euros ($14.9bn).
It has benefited from the success of the Walkman music phones and the decline of Motorola in the market, but will face a big challenge from the advance of the iPhone.
