STX Shipbuilding Co., the world's fifth-largest shipyard, fell the most in two months in Seoul trading after six executives at a unit were indicted for stealing technology from a rival.
The shipbuilder's shares dropped 7.3 percent to 53,000 won at the close. The stock has fallen about a third since Nov. 8, the day before prosecutors detained two of the six executives.
The six executives took files with them when they left Doosan Heavy Industries
& Construction Co. to join STX Heavy Industries Co., said the official in charge of the case at the prosecutors' office in Seoul.
STX Corp., the shipbuilder's biggest shareholder, declined 7.2 percent to 88,200 won. Doosan Heavy gained 0.7 percent to 139,000 won after falling as much as 9.1 percent.