South Korean stocks rallied sharply at the open on the 20th after the U.S. Treasury said it would double its long-term Treasury buyback program to at least $4 billion per operation from $2 billion. Lower Treasury yields helped revive risk appetite, with the Kospi rising 2.58% to 6,638.35 as of 9:04 a.m. after opening at 6,680.35 and gaining as much as 3.23%. Retail investors were net buyers of 298.4 billion won on the Kospi, while foreign and institutional investors were net sellers. The Kosdaq rose 2.66% to 846.42, with retail and institutional investors buying and foreign investors selling. Nine of the 10 largest Kosdaq stocks by market capitalization advanced. Wall Street also closed modestly higher after the announcement, although foreign selling in South Korea indicated that short-term profit-taking pressure remained.