A sharp increase in Middle Eastern oil prices is weighing on South Korean stocks, with airlines, chemical makers and refiners all facing pressure. Dubai crude, the country’s main import grade, rose 21.3% to $123.66 a barrel by the 11th from $101.91 on the 4th, while the complex refining margin fell for a sixth consecutive week to $26.4 a barrel. Refiners have struggled to benefit because crude purchase costs have risen as quickly as product prices, while airlines and petrochemical companies face higher fuel and feedstock expenses. On the 14th, the KOSPI fell 3.26% to 6,684.37 as concerns over the pace of U.S. artificial intelligence investment added to oil-related pressure. The Korea Exchange also opened its after-hours market, extending trading until 8 p.m. to allow responses to external developments such as oil prices and U.S. equities.