SINGAPORE: Refining margins for high sulphur fuel oil (HSFO) posted weekly gains of over 4% on Friday, supported by a decline in crude prices week-on-week.

The front-month crack for 180-cst HSFO was at a discount of $21.60 per barrel at the Asia close (0830 GMT), rising about 4.7% week-on-week, Refinitiv data showed.