SK Networks Co., the trading unit of South Korea's third-largest conglomerate SK Group, said Wednesday its net loss in the fourth quarter of 2013 soared from a year ago due to decreased sales and overseas investment.

The loss came to 434.11 billion won ($402.1 million) in the October-December period, compared with a net loss of 38.25 billion won a year ago, the company said in a regulatory filing.

Sales fell 5.7 percent to 6.49 trillion won in the period, but operating profit rose 17.1 percent to 98.2 billion won.

For all of 2013, SK Networks recorded a net loss of 604.21 billion won, swinging to red from a net profit of 11.94 billion won the previous year. Operating profit fell 4.1 percent to 241.21 billion won and sales dropped 7 percent to 25.98 trillion won.

"We posted a net loss last year partly due to a loss of about 500 billion won from our investment in a Brazilian iron ore company, which was made in the fourth quarter," SK Networks said. In September 2010, the company had invested $700 million in MMX Mineracao & Metalicos SA., an ore miner.

"However, there will be no additional loss (from the investment) this year as all potential losses have already been reflected," the company said.

The company predicted that its businesses such as natural resources exploration and trading will turn for the better this year as the global economic recovery is underway.

"This year will be a turning point for better earnings as we completed our pre-emptive restructuring and are making our investment and assets more efficient," SK Networks said. (Yonhap News)