Korean shares post worst week since March on tech selloff (updated)

Samsung Electronics Co

05/06/2026 06:25

KOSPI falls, foreigners net sellers
Korean won steady against dollar
South Korea benchmark bond yield flat
Updates to market close
SEOUL, June 5 (Reuters) - South Korean stocks plunged on Friday to post their steepest weekly drop since late March as a global tech pullback and stalling U.S.-Iran peace talks heavily dented investor risk appetite.
The Korean won hit its lowest against the dollar since 2009 while bond yields spiked, prompting government officials including finance minister Koo Yun-cheol to issue a verbal warning against speculative one-way bets.
On Wall Street, Broadcom AVGO.O tumbled more than 12%, pulling semiconductor stocks elsewhere lower, after the chipmaker's results disappointed investors who had bet on surging demand for its custom AI chips. The Philadelphia semiconductor index .SOX lost 2.2%.
Korea's benchmark KOSPI .KS11 closed down 478.82 points, or 5.54%, at 8,160.59, marking its biggest daily percentage fall since May 15. It ended the week down 3.7%.
During the session, the KOSPI fell as much as 6.96%, triggering a "sidecar" trading curb. 
Chipmaker Samsung Electronics 005930.KS fell 6.4% and peer SK Hynix 000660.KS dropped 9.9%. 
The two chipmakers have been rewriting global equity rankings, helping lift KOSPI by more than 200% over the past year.
The firms' outsized influence in the $5.01 trillion stock market has both excited investors and raised concerns about risks of the market overheating.
Hyundai Motor 005380.KS and sister automaker Kia Corp 000270.KS were unchanged and down 1.95%, respectively. Steelmaker POSCO Holdings 005490.KS shed 2.99%, while drugmaker Samsung BioLogics 207940.KS fell 0.74%.
Foreigners were net sellers of shares worth 3.5 trillion won  ($2.27 billion). Of the total 923 traded issues, 225 shares advanced, while 672 declined.
"Funds that have been overweight Korean equities to start are likely facing concentration limits at this point, and we understand single-stock concentration limits may also be a factor motivating investors to sell," Michael Loh of JPMorgan Chase Bank wrote in a report. 
The won KRW=KFTC, down almost 7% against the greenback so far this year, was quoted at 1,539.1 per dollar, down 0.46% on the day, after hitting its weakest level since March 2009 at 1,549.1 earlier in the session. 
In money and debt markets, June futures on three-year treasury bonds KTBc1 lost 0.01 point to 102.94.
The most liquid three-year Korean treasury bond yield KR3YT=RR rose by 1.7 basis points to 3.871%, while the benchmark 10-year yield KR10YT=RR rose by 0.7 basis points to 4.236%.

($1 = 1,544.3000 won)

 (Reporting by Cynthia Kim; Editing by Subhranshu Sahu; Editing by Sam Holmes)
 ((Cynthia.Kim@thomsonreuters.com; 822 3704 5655; Reuters Messaging: cynthia.kim.thomsonreuters.com@reuters.net))