South Korea's bond trading volume dropped to its lowest mark in over four years in the first quarter as signs of economic recovery and the U.S. Fed's tapering made investors turn to risky assets over safer debts, data showed Thursday. The turnover of the local bond market came to 1,269 trillion won (US$1.12 trillion) in the January-March period, the lowest on a quarterly basis since the fourth quarter of 2009 when the comparable figure was 1,139 trillion won, according to the data by the Korea Financial Investment Association and the Korea Exchange.