KOSPI on June 22 turned higher after early weakness and finished trading around the 9,110 level, setting another record high close. SK Hynix surged and overtook Samsung Electronics to become the No. 1 stock by market capitalisation on the KOSPI for the first time in 25 years and 7 months.

The KOSPI ended up 62.13 points, or 0.69 percent, at 9,114.55. The index opened down 97.99 points, or 1.08 percent, at 8,954.43 and fell as low as the 8,900 level during the session, but later turned higher and closed at a record.

Individuals and institutions supported the market. In the main bourse, individuals were net buyers of 2.1217 trillion won and institutions bought a net 330.6 billion won. Foreigners, meanwhile, sold a net 2.5443 trillion won.

Among heavyweight stocks, SK Hynix was strong. It finished up 155,000 won, or 5.61 percent, at 2,919,000 won. Its intraday high was 2,945,000 won. Samsung Electronics ended down 500 won, or 0.14 percent, at 353,500 won.

By the close, SK Hynix's market capitalisation was tallied at 2,080.3782 trillion won and Samsung Electronics' at 2,066.6595 trillion won. SK Hynix led Samsung Electronics by about 13.7187 trillion won, making it the top stock by market value on the KOSPI.

It was the first time Samsung Electronics has given up the top spot by market value in the domestic stock market since it rose to No. 1 by overtaking Korea Telecom Authority, now KT, in 2000.

Elsewhere, SK Square rose 10.67 percent and Samsung C&T gained 5.80 percent.

Samsung Electro-Mechanics fell 1.85 percent, while Hyundai Motor dropped 5.22 percent. LG Energy Solution slid 4.70 percent, Samsung Life fell 9.36 percent and HD Hyundai Heavy Industries lost 4.65 percent.

KOSDAQ also edged higher. It ended up 1.81 points, or 0.19 percent, at 968.40. The index was weak during the session but trimmed losses in the afternoon and finished higher.

In the Seoul foreign exchange market, the won stood at 1,539.00 per dollar, down 6.00 won from the previous session.

In the securities industry, there is a view that SK Hynix overtaking Samsung Electronics in market value is a symbolic scene of a strong semiconductor market, while also saying the possibility of short-term overheating should be checked.

The view is that SK Hynix was quickly re-rated based on its HBM competitiveness, but a recovery in Samsung Electronics' share price is also needed for further gains in the KOSPI.

Lee Jae-man (이재만), a researcher at Hana Securities, said, "In terms of valuation, SK Hynix is in a more expensive situation than Samsung Electronics," and added, "It is judged to be one of the short-term overheating signals that can occur in a strong market."

Lee said, "For the KOSPI to rise further in the future, the pace of Samsung Electronics' share price increase must become faster than SK Hynix," and added, "The second-quarter profit growth rates of Samsung Electronics and SK Hynix are high, but it is also necessary to consider the possibility that the pace of share price gains could slow as the second-quarter peak passes."