Brent crude futures were down 90 cents, or 1.14%, at $78.1 a barrel by 11:40 a.m. EST (1640 GMT). U.S. West Texas Intermediate crude (WTI) fell $1.01, or 1.34%, to $74.43.

The World Economic Forum, colloquially called "Davos" after the location at which it's hosted in the Swiss mountains, is a yearly meeting of elites.

U.S. President Trump is to speak to an international audience for the first time after returning into the White House with a speech and Q&A by video conference to the World Economic Forum’s annual event in Davos on Thursday.