Profits made by South Korea's listed firms plunged nearly 40 percent in the first quarter of this year due to weaker exports.

According to the Korea Exchange and the Korea Listed Companies Association on Friday, the combined net profit of 573 non-financial companies on the KOSPI totaled 20-point-nine trillion won in the first quarter, down 39 percent from a year ago.

Sales by the firms edged up zero-point-two percent to 484-point-three trillion won, while their operating profits dipped 37 percent to 27-point-eight trillion won.

The falling profits were mostly attributed to a decline in South Korea's exports amid a renewed trade war between the U.S. and China, as well as the global economic slowdown.

Amid flagging overseas demand for chips, South Korea's semiconductor exports tumbled 21-point-four percent between January and March, while combined sales for Samsung Electronics and SK Hynix sank 14-point-six percent.