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.
, 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.