S-Oil said Oct. 23 its third-quarter net profit plunged 77.6 percent from a year earlier on inventory losses and a weak Korean won.

Net profit for the three months ending Sept. 30 came to 51.6 billion won ($43 million), compared with a net profit of 229.8 billion won a year earlier, the company said in a statement.

Operating profit dropped 26.9 percent on-year to 230.7 billion won, while its sales fell 13.3 percent on-year to 6.2 trillion won during the cited period.

However, compared with the previous quarter, S-Oil swung to the black, thanks to improved refining margins.

S-Oil said its poor third-quarter earnings stemmed from fluctuating oil prices that caused inventory losses coupled with the Korean won’s weakness against the US dollar.

The company said it posted a 109.4 billion-won loss in foreign exchanges in the July-September period, compared with 24.7 billion won profit a year earlier. It also suffered a 45.6 billion-won loss in interest payments in the cited period.

Its refining business posted a 99.7 billion-won operating profit in the third quarter, compared with a 170.4 billion-won operating profit a year ago. Its petrochemical sector achieved an operating profit of 79.4 billion won, down 22.2 percent from a year earlier.

By Ram Garikipati and newswires (ram@heraldcorp.com)