Taiwan's Formosa Petrochemical stock rose sharply as fears of supply disruptions in the Middle East kept oil prices near four-week highs — good for refiners, bad for anyone buying fuel.

• Talks between the US and Iran are going nowhere, and shipping traffic through the strait has thinned out, keeping oil above $90 a barrel.
• Formosa Petrochemical shares climbed as much as 6% in early trading on heavy volume.
• Tight fuel supply in the Middle East, plus cautious exports from Northeast Asian refineries, has pushed up what the company gets per barrel.
• Higher electricity sales and stronger ethylene volumes are adding to revenue growth.
• Big institutions were actually selling the stock the day before, led by Morgan Stanley and JPMorgan — a sign not everyone is convinced the rally lasts.

Outlook: If shipping through the Strait of Hormuz stays blocked, oil should hold near $90 and keep refining margins strong.