Seoul: S-Oil Corp., South Korea's third-largest refiner by sales, announced on Monday a return to net profitability in the fourth quarter, largely attributed to the weakening of the Korean won.

According to Yonhap News Agency, S-Oil's net profit for the fourth quarter reached 265 billion won (US$183 million), a significant turnaround from the 131.7 billion won loss recorded in the same period the previous year. The company's operating profit increased 90.9 percent from the previous year to 424.5 billion won, although revenue experienced a slight decline of 1.4 percent, totaling 8.79 trillion won.

The reported earnings, however, did not meet market expectations. Analysts surveyed by Yonhap Infomax, the financial data division of Yonhap News Agency, had projected an average net profit estimate of 278.1 billion won. The company explained that the improved profitability was due in part to the weaker local currency, which enhanced won-denominated profits.

S-Oil's primary refining business experienced over a 50 percent year-on-year increase due to seasonal demand and reduced crude oil prices, although its petrochemical division continued to incur losses. Looking ahead, S-Oil anticipates that stable global demand and low crude oil prices will impact its refining business positively in the first quarter.

In a broader context, S-Oil reported an annual net profit of 216.9 billion won for 2025, a reversal from a 193 billion won loss the previous year. Despite this, the company's annual operating profit decreased by 31.7 percent year-on-year to 288.2 billion won, and sales saw a decline of 6.5 percent, amounting to 34.24 trillion won.