US base oils imports fell to an eighteen-month low in December, curbing the size of a typical supply-build at year-end.It also extended a recent pattern of unusually volatile import volumes every month since August.Base oils imports of 949,400 barrels (134,000 tonnes) in December fell from 1.65 million barrels the previous month, government data showed.The November volume was the second-highest in more than two years and followed a slump in shipments the previous month.The trend of higher, then lower monthly shipments showed signs of extending into early next year, with imports in January likely to have risen strongly from December. The slump in imports in December coincided with unexpected base oils production issues in the US in second-half November that continued into early December.The production issues were one factor behind a fall in US base oils output to a one-year low in November.The continuation of those issues into December could have kept US base oils output levels lower than usual that month as well.Any such extended slowdown in production from typical levels, combined with lower base oils imports, would cut further the country’s domestic base oils supply at the end of the year.Any significant fall in US base oils supply would in turn cushion the impact of a seasonal slowdown in domestic demand and build-up of surplus volumes at year-end.Steady US base oils prices so far this year, and a rise in posted prices for some grades in recent weeks, contrasted with a further drop in base oils prices during the first three months of 2024.The steadier prices suggested that any pressure from surplus supply was more muted this year than last year. More muted pressure pointed to a smaller surplus.US base oils imports fell in December mostly because of a slump in shipments from Qatar.The slowdown mirrored a similar drop in Asia’s base oils imports from Qatar in December.Imports from other key sources like Bahrain, UAE and South Korea held firmer at more typical levels..US' Dec base oils exports stay lower.S Korea Dec exports to Americas mixed.US’ November base oils output falls.Base Oil News stories and analysis also available on ICIS platform