Samsung has warned investors that it will report weaker than expected earnings for the last quarter, according to the WSJ. It's believed that sales of the company's flagship Galaxy S4 have been lower than expected.

The world's biggest smartphone maker by shipments said Friday it expects an operating profit of between 9.3 trillion won and 9.7 trillion won ($8.2 billion and $8.5 billion) for the three months ended June 30. That represents growth of 44% to 50% from the 6.46 trillion won in operating profit posted a year earlier, and a slowing from the 54% rise in operating profit in the first quarter. Sales are expected to come in between 56 trillion won and 58 trillion won, up by 18% to 22% from 47.60 trillion won a year earlier.

Samsung shares dropped 3.9% on the news lowering the company's market cap by $6.5 billion. The company has lost $32.7 billion in market cap since mid-March when reports started to emerge of weaker than expected Galaxy S4 sales.