Increased marketing costs in wake of changing competitive scenario led to 57 % drop in net profits for Korea''s SK Telecom as the company posted net profits of 333.6 billion won ($228.8 million) as compared to 776.8 billion won profit a year earlier. Sales rose 3 % to 2.9 trillion won.

Marketing costs, which include expenses for subsidizing handsets, rose 2 % to 728 billion won, slowing from the 25 % increase in the second quarter.

The company said the drop is also reflected because last year's comparison is on a higher base due to its acquiring stake in China's Unicom.

Operating profit, or sales minus the cost of goods sold and administrative expenses, fell 6.1 % to 504.1 billion won as compared to year earlier figures, when the company posted a 373.1 billion won gain from swapping stake in China Unicom Ltd.

SK Telecom said losses related to foreign-currency and derivative products increased more than sixfold from a year earlier to 265 billion won. Operating profit fell after investments on faster networks pushed up depreciation expenses, said the company.

SK Telecom shares fell 6.7 % to close at 187,500 on the Korea Exchange, while the benchmark Kospi index gained 5.6 %.