Employees of Kakao Games netted 16.7 billion won ($15 million) in gains by exercising stock options after the games unit of Korea’s mobile giant Kakao successfully debuted on the Kosdaq market in September.

According to a regulatory filing Tuesday, a significant number of Kakao Games employees exercised stock options to purchase 473,678 shares at the average price of 13,000 won on Sept. 23, two weeks after the company went public.

In total, the employees spent 6.3 billion won to buy the stocks. Now, those stocks are valued at 23 billion won, calculated based on Monday’s closing price of 48,600 won per share. As a result, Kakao Games employees made 16.7 billion won in profit margin, or 52 million won each.

Kakao Games initially granted 6 million shares as stock options to employees. As of the end of September, employees haven’t exercised stock options on 2.7 million shares. Among the 2.7 million shares, 1 million shares are in the vesting period, meaning that employees will have to wait for a certain period of time if they want to exercise stock options on them in the future.

By Kim Byung-wook (kbw@heraldcorp.com)