Saudi Aramco cut its key Asian oil prices for January as expected, but the key question is whether the drop is big enough to tempt refiners to buy more crude.

Aramco 2222.SE, the world’s largest crude oil exporter, slashed the official selling price (OSP) for its flagship Arab Light to a premium of $3.25 per barrel over the Oman/Dubai regional reference prices for cargo in January.

This was a $2.20 per barrel drop from the $5.45 premium on freight shipped in…