S-Oil Corp., the No. 3 oil refiner in South Korea, said Thursday that its earnings doubled last year from a year earlier, helped by a surge in its refining margins and widening spreads for chemicals goods.

Net profit reached 1.26 trillion won ($1.1 billion) last year, compared with a profit of 631 billion won a year earlier, the company said in a regulatory filing.

Operating income also more than doubled to a record 1.69 trillion won from 817 billion won over the cited period, while sales dipped 8.8 percent on-year to 16.32 trillion won.

The company reaped 758 billion won in operating income from its refining business, while its chemicals business racked up an operating income of 517 billion won.

Its lubricant unit also logged an operating income of 419 billion won.

Its operating income to margin ratio stood at 10.4 percent, it added. (Yonhap)