Glitch in high-speed trading in U.S. sparks market slide worldwide

A rise in the use of computers has transformed trading during the past couple of decades, leading to a glitch in high-frequency trading Thursday that caused markets worldwide to tumble. The glitch briefly erased in excess of $1 trillion in market value in the U.S., exacerbating a sell-off caused by the sovereign-debt crisis in Europe. Asian share markets then started to fall but quickly stabilized. However, many questions remain, with U.S. regulators examining the activity.