South Korea's financial markets watchdog, the Financial Supervisory Service (FSS), is not currently investigating Hyundai Motor executives' sales of shares in the automaker, a regulatory official said on Tuesday. The official made the statement after some retail investors expressed concerns in online stock forums over the possibility of insider trading by Hyundai executives who sold shares in recent weeks. Reports of possible co-operation between Hyundai and tech giant Apple on a self-driving electric vehicle that emerged early in January sent Hyundai stock sharply higher, adding billions of dollars to its market value.