SEOUL, April 5 (Yonhap) -- The number of active accounts for stock trading in South Korea declined in March from a month earlier amid a prolonged bear market stemming from rising economic and political uncertainties, data showed Friday. South Korean investors held 18.9 million active stock accounts as of end-March, down 3.9 percent from 19.7 million accounts tallied in end-February, according to the data compiled by the Korea Financial Investment Association.