Higher base oils output in Japan and Brazil added to signs that refiners maintained firm production levels despite pressure to prioritise motor fuels.
Europe entered the supply-disruption period with elevated availability of all base oils grades, with steady US flows and strong Netherlands output pointing to Group II availability remaining adequate through Q2.
US base oils supply rebounded in March, but demand rose even faster, leaving inventories unusually low and reducing the buffer against any additional supply disruption.
Strong lubricants demand in Japan and Argentina extended into April, pointing to stock-building continuing beyond March's initial buying spree.
Singapore's exports fell to a multi-year low in the past month, partially offsetting signs of firmer supply and run-rates elsewhere in Asia.
Falling imports into Japan and signs of weaker exports from South Korea and Indonesia pointed to growing tightness in Group III base oils supply.
As summer approaches, higher blender inventories and slowing procurement pointed to balanced-to-tight conditions, reducing the urgency that drove March and April buying.