S-Oil's Olefin Downstream Complex is seen in this undated photo. Courtesy of S-Oil

S-Oil, Korea's third-largest refiner by sales, said Friday its first-quarter net profit fell 37 percent from a year earlier on decreased refining margins.

Net profit for the three months ended in March declined to 166.2 billion won ($120.8 million) from 265.31 billion won in the year-ago period, the company said in a statement.

"Compared to the first quarter of 2023, lower refining margins of diesel and jet fuel products were reflected in the quarterly results," a company spokesperson said.

Operating profit dropped 12 percent to 454.1 billion won in the first quarter from 515.68 billion won a year ago. Sales were up 2.5 percent to 9.308 trillion won from 9.077 trillion won.

In the coming quarters, the company expected global demand for "transportation fuel," such as jet fuel and gasoline, will remain strong around the summer peak season.

Saudi Arabia's state-controlled Aramco holds a 63.4 percent stake in S-Oil. (Yonhap)