World shares are mixed after US Treasury expands debt buybacks, while Brent crude gains 2.2%

World shares showed mixed performance on Thursday, though Asian markets led with South Korea’s Kospi jumping nearly 6% and China's Hang Seng gaining 0.8%. Trading was influenced by the U.S. Treasury Department announcing plans to double its debt purchases, which eased concerns about rising bond yields. Furthermore, oil prices surged after little progress was made in U.S.-Iran negotiations, driving Brent crude up 2.2% to $93.61 a barrel.