Roundup: European stocks drop as ECB hikes rates

ROME, Dec. 15 (Xinhua) -- Europe's main stock exchanges retreated on Thursday and the euro currency surged against the U.S. dollar after the European Central Bank (ECB) announced it would begin a process of quantitative tightening early next year.

The ECB said on Thursday that starting in March, it would sell off around 15 billion euros (15.9 billion U.S. dollars) in national bonds each month as a way to raise i