Doosan Robotics Inc. more than doubled in its trading debut in Seoul after raising 421 billion won ($312 million) in South Korea’s largest initial public offering this year.

Shares of the robot maker surged as much as 160% to 67,600 won before paring the gain to about 100%. The company, with Seoul-listed Doosan Co. as its biggest shareholder, last month sold 16.2 million shares at 26,000 won each, the top of a marketed price range.