S-Oil Corp., the No. 3 oil refiner in South Korea, said Monday that its second-quarter net profit gained 3.8 percent from a year earlier, largely thanks to an improvement in its refining business and other areas.

Net profit reached 445 billion won ($391 million) on a consolidated basis in the April-June period, compared with a profit of 429 billion won a year earlier, the company said in a regulatory filing.

Sales dropped 18.4 percent on-year to reach 4.19 trillion won in the second quarter, while it logged an operating income of 643 billion won, up 6.1 percent over the cited period.

S-Oil said relatively higher cracking margins helped boost its bottom line, with other businesses such as its lubricants unit faring well.

S-Oil expects rising demand from Asia will continue to help refiners this year.

S-Oil closed at 77,300 won on the Seoul bourse, down 1.28 percent from the previous session's close. (Yonhap)