LG Chem Ltd., the world's largest lithium-ion battery maker, said Friday its net profit fell 23.3 percent in the third quarter of this year from a year ago on sluggish performance in the rubber sector.

Net profit came to 352 billion won ($332 million) in the July-September period, compared with 459 billion won a year ago, LG Chem said in a regulatory filing.

Sales rose a mere 0.5 percent to 5.87 trillion won in the same period, while operating profit fell 14 percent to 516 billion won.

LG Chem said the poor third-quarter earnings were due to weak performance in the rubber raw material sector as demand for tires decreased on a prolonged economic slump. The company also cited as a reason a weaker won bringing down the value of its overseas assets.

Meanwhile, LG Chem said its IT material sector posted an operating profit of 102 billion won in the third quarter, down 13.6 percent from the previous quarter, and sales of 788 trillion won, up 3.1 percent.

The company's petrochemical division logged an operating profit of 379 billion won, up 3.5 percent, and sales of 4.42 trillion won, down 2.4 percent.

Sales at its rechargeable battery division rose 14.4 percent to 707 billion won in the third quarter from a year earlier, while operating profit more than doubled to 34 billion won in the cited period.

Shares of LG Chem closed up 0.78 percent at 322,500 won on the Seoul bourse. (Yonhap News)