Samsung Electronics on Tuesday reported preliminary second-quarter operating profit of 89.4 trillion won ($58.4 billion), versus 57.2 trillion won in the prior period. Operating profit from the same period a year earlier was 4.7 trillion won. Samsung shares traded nearly 5% lower at Tuesday's open. The tech giant reported revenue for the April-to-June period of 171 trillion won, up from 133.9 trillion won in the previous quarter. The results...