The premium declined for two months in a row from January due to increasing supplies.
S-Oil will increase bunker fuel supply in March, said one trader, adding the refiner will sell around 200,000 mt of bunker fuel in March.
S-Oil did not reveal its sales volume for February, but a source close to the matter said it was around a half of the usual. The company typically sells around 160,000-200,000 mt/month, market sources said.
The company could not ship bunker fuel over February 9-20 because of strong winds at its 669,000 b/d Onsan refinery in the country`s southeast.
South Korean 380 CST bunker fuel was assessed at $632/mt Wednesday, a premium of $26.04/mt over MOPS 380 CST HSFO assessments, Platts data showed.
"Market sources expect March (premium) level to go down further to $21-22/mt," said a bunker fuel trader.
South Korean refiners had sufficient stocks at present, traders said.
South Korea sells about 700,000 mt/month of bunker fuel.