KOSPI Tumbles Below 6,400 as Hangul Day Holiday Ends

The KOSPI fell more than 3 percent on Tuesday, the first trading day after the Hangul Day holiday ended, slipping to the 6,300 level for the first time in about two months. The index opened slightly lower at around 6,580 before extending its losses through the session.

Selling pressure was concentrated in large-cap semiconductor stocks. Concerns over a supply-demand gap grew after Samsung Electronics and SK hynix wrapped up their share buyback programs. The two stocks indeed fell more than 4 percent together, dragging down the index.

Fears that the strong won could slow exporters' earnings also weighed on the market. Lee Sang-yeon, a researcher at Shin Young Securities, said, "The rapid appreciation of the won has raised concerns about the earnings momentum of exporters," adding, "Someone needs to step in as a buyer after the buyback programs ended, but there has been no significant buying from foreigners or institutions so far."

SK hynix's earnings release and Samsung Electronics' conference call are scheduled for the end of this month.

The KOSDAQ also plunged more than 4 percent, falling below the 850 mark. In the Seoul foreign exchange market, the won traded at 1,335.1 per dollar as of 3:30 p.m., down 7.7 won from the previous session.