Nearly 20 percent of executives at South Korea's major companies were either dismissed or stepped down in the past year amid efforts to streamline business portfolios, data showed Thursday.

The total number of registered and non-registered executives at flagship companies of the country's top 10 business groups stood at 2,585 at the end of June, down 47 from a year earlier, according to the data compiled by corporate tracker Chaebul.com.

The 10 surveyed companies are Samsung Electronics Co., Hyundai Motor Co., SK Innovation Co., LG Electronics Inc., Lotte Shopping Co., POSCO, GS Caltex Corp., Hyundai Heavy Industries Co., Korean Air Lines Co. and Hanwha Corp.

Over the one-year period, 467 executives, or 18.1 percent, stepped down or were dismissed, while 420 advanced to fill the vacant posts.

Tech giant Samsung Electronics discharged 189 high-ranking officials, or 15.5 percent of its executives, in the previous 12 months, with 162 new faces coming to fill posts.

Hyundai Motor, the country's largest automaker, let go of 40 executives and added 54, while 39 officials left LG Electronics, No. 2 home appliances maker, and 44 were hired. (Yonhap)