South Korean shares closed higher on Thursday after investors went on a stock purchasing spree amid growing optimism over a possible U.S.-Iran peace agreement and Samsung Electronics' (KRX:005930) tentative wage deal with its labor union.
The Korea Composite Stock Price Index or Kospi jumped by 606.64 points, or 8.4%, to end at 7,815.59. The Kosdaq also increased by 49.9 points, or 4.7%, to close at 1,105.97.
The strong gains earlier in the day had led the Korea Exchange to activate a five-minute buy-side sidecar on the country's primary and secondary stock to prevent market overheating.
In economic news, producer prices in South Korea increased 6.9% in April from a year earlier, accelerating from 4.1% in March and marking the strongest increase since October 2022, according to preliminary data from the Bank of Korea on Thursday.
In corporate developments, Samsung and its largest labor union appeared to agree on a proposed wage agreement, which suspended plans for a strike scheduled from May 21 to June 7.
Under the proposal, Samsung Electronics will introduce a special performance bonus program for semiconductor employees tied to profitability. The 10-year scheme sets annual profit targets of 200 trillion won from 2026 to 2028 and 100 trillion won from 2029 to 2035, the report said.
Shares of the chipmaker jumped nearly 9% at market close on Thursday.