South Korean stocks climbed for a fourth straight session on Wednesday to a new record above the 8,200-point level, led by strong gains in Samsung Electronics (KRX:005930) and SK Hynix (KRX:000660), which added nearly 3% and over 9% respectively.
Investors also assessed renewed Middle East tensions alongside efforts toward a peace agreement between the U.S. and Iran.
The Korea Composite Stock Price Index or Kospi jumped by 181.19 points, or 2.3%, to end at 8,228.7. The Kosdaq decreased by 39.39 points, or 3.4%, to close at 1,133.13.
In economic news, the composite business sentiment index in all industries in South Korea increased four points to 98.9 in May from 94.9 in April, while the outlook for the next month added 3.7 points to 97.6, according to data released by the Bank of Korea on Wednesday.
The latest print marked the highest in over three years.
The seasonally adjusted composite business sentiment index for the manufacturing sector added 1.7 points to 100.8, while the outlook for the following month also added 2.3 points to 100.3, the central bank said.
For the non-manufacturing sector, the seasonally adjusted composite business sentiment index increased 5.4 points to 97.5, while the outlook for the following month added 4.7 points to 95.9.
In corporate news, Aamajority of Samsung Electronics' largest labor union approved a compensation agreement that will provide chip workers with average bonuses of about 513 million won, or $340,000 each, Bloomberg News reported Wednesday.
Around 74% of union members backed the deal after weeks of negotiations.
The move follows a similar bonus payout agreement reached in 2025 by competitor SK Hynix, though Samsung's actual bonus payments will largely depend on earnings and chip demand.
In other news, Samsung Electronics also plans to invest $1.5 billion in Vietnam to build its first chip testing factory in the country, The Economic Times reported Wednesday, referring to a company document reviewed by Reuters.
Construction has already begun at an industrial park about 60 kilometers north of the Vietnamese capital of Hanoi, with operations expected to start in November 2027.